Split 0x.js into contract-wrappers, order-watcher but keep 0x.js as a unifying library with the same interface

28 files changed, 62 insertions, 3954 deletions

diff --git a/packages/0x.js/src/0x.ts b/packages/0x.js/src/0x.ts
index 78f9f6beb..e670bd0c5 100644
--- a/packages/0x.js/src/0x.ts
+++ b/packages/0x.js/src/0x.ts
@@ -1,4 +1,13 @@
-import { schemas, SchemaValidator } from '@0xproject/json-schemas';
+import { assert } from '@0xproject/assert';
+import {
+    ContractWrappers,
+    EtherTokenWrapper,
+    ExchangeWrapper,
+    TokenRegistryWrapper,
+    TokenTransferProxyWrapper,
+    TokenWrapper,
+    ZeroExContractConfig,
+} from '@0xproject/contract-wrappers';
 import {
     generatePseudoRandomSalt,
     getOrderHashHex,
@@ -6,27 +15,13 @@ import {
     isValidSignature,
     signOrderHashAsync,
 } from '@0xproject/order-utils';
+import { OrderWatcher, OrderWatcherConfig } from '@0xproject/order-watcher';
 import { ECSignature, Order, Provider, SignedOrder, TransactionReceiptWithDecodedLogs } from '@0xproject/types';
-import { AbiDecoder, BigNumber, intervalUtils } from '@0xproject/utils';
+import { BigNumber } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
-import * as ethUtil from 'ethereumjs-util';
 import * as _ from 'lodash';
 
-import { artifacts } from './artifacts';
-import { EtherTokenWrapper } from './contract_wrappers/ether_token_wrapper';
-import { ExchangeWrapper } from './contract_wrappers/exchange_wrapper';
-import { TokenRegistryWrapper } from './contract_wrappers/token_registry_wrapper';
-import { TokenTransferProxyWrapper } from './contract_wrappers/token_transfer_proxy_wrapper';
-import { TokenWrapper } from './contract_wrappers/token_wrapper';
-import { OrderStateWatcher } from './order_watcher/order_state_watcher';
-import { zeroExConfigSchema } from './schemas/zero_ex_config_schema';
-import { zeroExPrivateNetworkConfigSchema } from './schemas/zero_ex_private_network_config_schema';
-import { zeroExPublicNetworkConfigSchema } from './schemas/zero_ex_public_network_config_schema';
-import { OrderStateWatcherConfig, ZeroExConfig, ZeroExError } from './types';
-import { assert } from './utils/assert';
 import { constants } from './utils/constants';
-import { decorators } from './utils/decorators';
-import { utils } from './utils/utils';
 
 /**
  * The ZeroEx class is the single entry-point into the 0x.js library. It contains all of the library's functionality
@@ -62,7 +57,7 @@ export class ZeroEx {
      * tokenTransferProxy smart contract.
      */
     public proxy: TokenTransferProxyWrapper;
-    private _web3Wrapper: Web3Wrapper;
+    private _contractWrappers: ContractWrappers;
     /**
      * Generates a pseudo-random 256-bit salt.
      * The salt can be included in a 0x order, ensuring that the order generates a unique orderHash
@@ -136,40 +131,15 @@ export class ZeroEx {
      * @param   config      The configuration object. Look up the type for the description.
      * @return  An instance of the 0x.js ZeroEx class.
      */
-    constructor(provider: Provider, config: ZeroExConfig) {
+    constructor(provider: Provider, config: ZeroExContractConfig) {
         assert.isWeb3Provider('provider', provider);
-        assert.doesConformToSchema('config', config, zeroExConfigSchema, [
-            zeroExPrivateNetworkConfigSchema,
-            zeroExPublicNetworkConfigSchema,
-        ]);
-        const artifactJSONs = _.values(artifacts);
-        const abiArrays = _.map(artifactJSONs, artifact => artifact.abi);
-        const defaults = {
-            gasPrice: config.gasPrice,
-        };
-        this._web3Wrapper = new Web3Wrapper(provider, defaults);
-        _.forEach(abiArrays, abi => {
-            this._web3Wrapper.abiDecoder.addABI(abi);
-        });
-        this.proxy = new TokenTransferProxyWrapper(
-            this._web3Wrapper,
-            config.networkId,
-            config.tokenTransferProxyContractAddress,
-        );
-        this.token = new TokenWrapper(this._web3Wrapper, config.networkId, this.proxy);
-        this.exchange = new ExchangeWrapper(
-            this._web3Wrapper,
-            config.networkId,
-            this.token,
-            config.exchangeContractAddress,
-            config.zrxContractAddress,
-        );
-        this.tokenRegistry = new TokenRegistryWrapper(
-            this._web3Wrapper,
-            config.networkId,
-            config.tokenRegistryContractAddress,
-        );
-        this.etherToken = new EtherTokenWrapper(this._web3Wrapper, config.networkId, this.token);
+        this._contractWrappers = new ContractWrappers(provider, config);
+
+        this.proxy = this._contractWrappers.proxy;
+        this.token = this._contractWrappers.token;
+        this.exchange = this._contractWrappers.exchange;
+        this.tokenRegistry = this._contractWrappers.tokenRegistry;
+        this.etherToken = this._contractWrappers.etherToken;
     }
     /**
      * Sets a new web3 provider for 0x.js. Updating the provider will stop all
@@ -178,31 +148,23 @@ export class ZeroEx {
      * @param   networkId   The id of the network your provider is connected to
      */
     public setProvider(provider: Provider, networkId: number): void {
-        this._web3Wrapper.setProvider(provider);
-        (this.exchange as any)._invalidateContractInstances();
-        (this.exchange as any)._setNetworkId(networkId);
-        (this.tokenRegistry as any)._invalidateContractInstance();
-        (this.tokenRegistry as any)._setNetworkId(networkId);
-        (this.token as any)._invalidateContractInstances();
-        (this.token as any)._setNetworkId(networkId);
-        (this.proxy as any)._invalidateContractInstance();
-        (this.proxy as any)._setNetworkId(networkId);
-        (this.etherToken as any)._invalidateContractInstance();
-        (this.etherToken as any)._setNetworkId(networkId);
+        this._contractWrappers.setProvider(provider, networkId);
     }
     /**
      * Get the provider instance currently used by 0x.js
      * @return  Web3 provider instance
      */
     public getProvider(): Provider {
-        return this._web3Wrapper.getProvider();
+        return this._contractWrappers.getProvider();
     }
     /**
      * Get user Ethereum addresses available through the supplied web3 provider available for sending transactions.
      * @return  An array of available user Ethereum addresses.
      */
     public async getAvailableAddressesAsync(): Promise<string[]> {
-        const availableAddresses = await this._web3Wrapper.getAvailableAddressesAsync();
+        // Hack: Get Web3Wrapper from ZeroExContract
+        const web3Wrapper = (this._contractWrappers as any)._web3Wrapper;
+        const availableAddresses = await web3Wrapper.getAvailableAddressesAsync();
         return availableAddresses;
     }
     /**
@@ -223,7 +185,7 @@ export class ZeroEx {
         shouldAddPersonalMessagePrefix: boolean,
     ): Promise<ECSignature> {
         return signOrderHashAsync(
-            this._web3Wrapper.getProvider(),
+            this._contractWrappers.getProvider(),
             orderHash,
             signerAddress,
             shouldAddPersonalMessagePrefix,
@@ -241,7 +203,9 @@ export class ZeroEx {
         pollingIntervalMs = 1000,
         timeoutMs?: number,
     ): Promise<TransactionReceiptWithDecodedLogs> {
-        const transactionReceiptWithDecodedLogs = await this._web3Wrapper.awaitTransactionMinedAsync(
+        // Hack: Get Web3Wrapper from ZeroExContract
+        const web3Wrapper = (this._contractWrappers as any)._web3Wrapper;
+        const transactionReceiptWithDecodedLogs = await web3Wrapper.awaitTransactionMinedAsync(
             txHash,
             pollingIntervalMs,
             timeoutMs,
@@ -249,22 +213,16 @@ export class ZeroEx {
         return transactionReceiptWithDecodedLogs;
     }
     /**
-     * Instantiates and returns a new OrderStateWatcher instance.
+     * Instantiates and returns a new OrderWatcher instance.
      * Defaults to watching the pending state.
      * @param   config      The configuration object. Look up the type for the description.
-     * @return  An instance of the 0x.js OrderStateWatcher class.
-     */
-    public createOrderStateWatcher(config?: OrderStateWatcherConfig) {
-        return new OrderStateWatcher(this._web3Wrapper, this.token, this.exchange, config);
-    }
-    /*
-     * HACK: `TokenWrapper` needs a token transfer proxy address. `TokenTransferProxy` address is fetched from
-     * an `ExchangeWrapper`. `ExchangeWrapper` needs `TokenWrapper` to validate orders, creating a dependency cycle.
-     * In order to break this - we create this function here and pass it as a parameter to the `TokenWrapper`
-     * and `ProxyWrapper`.
-     */
-    private async _getTokenTransferProxyAddressAsync(): Promise<string> {
-        const tokenTransferProxyAddress = await (this.exchange as any)._getTokenTransferProxyAddressAsync();
-        return tokenTransferProxyAddress;
+     * @return  An instance of the 0x.js OrderWatcher class.
+     */
+    public async createOrderWatcherAsync(config?: OrderWatcherConfig) {
+        // Hack: Get Web3Wrapper from ZeroExContract
+        const web3Wrapper = (this._contractWrappers as any)._web3Wrapper;
+        const networkId = web3Wrapper.getNetworkIdAsync();
+        const provider = this._contractWrappers.getProvider();
+        return new OrderWatcher(provider, networkId, config);
     }
 }
diff --git a/packages/0x.js/src/abstract/balance_and_proxy_allowance_fetcher.ts b/packages/0x.js/src/abstract/balance_and_proxy_allowance_fetcher.ts
deleted file mode 100644
index c357f8447..000000000
--- a/packages/0x.js/src/abstract/balance_and_proxy_allowance_fetcher.ts
+++ /dev/null
@@ -1,6 +0,0 @@
-import { BigNumber } from '@0xproject/utils';
-
-export abstract class BalanceAndProxyAllowanceFetcher {
-    public abstract async getBalanceAsync(tokenAddress: string, userAddress: string): Promise<BigNumber>;
-    public abstract async getProxyAllowanceAsync(tokenAddress: string, userAddress: string): Promise<BigNumber>;
-}
diff --git a/packages/0x.js/src/abstract/order_filled_cancelled_fetcher.ts b/packages/0x.js/src/abstract/order_filled_cancelled_fetcher.ts
deleted file mode 100644
index 81ae04b9c..000000000
--- a/packages/0x.js/src/abstract/order_filled_cancelled_fetcher.ts
+++ /dev/null
@@ -1,6 +0,0 @@
-import { BigNumber } from '@0xproject/utils';
-
-export abstract class OrderFilledCancelledFetcher {
-    public abstract async getFilledTakerAmountAsync(orderHash: string): Promise<BigNumber>;
-    public abstract async getCancelledTakerAmountAsync(orderHash: string): Promise<BigNumber>;
-}
diff --git a/packages/0x.js/src/artifacts.ts b/packages/0x.js/src/artifacts.ts
deleted file mode 100644
index a91d9ae1f..000000000
--- a/packages/0x.js/src/artifacts.ts
+++ /dev/null
@@ -1,18 +0,0 @@
-import * as DummyTokenArtifact from './compact_artifacts/DummyToken.json';
-import * as EtherTokenArtifact from './compact_artifacts/EtherToken.json';
-import * as ExchangeArtifact from './compact_artifacts/Exchange.json';
-import * as TokenArtifact from './compact_artifacts/Token.json';
-import * as TokenRegistryArtifact from './compact_artifacts/TokenRegistry.json';
-import * as TokenTransferProxyArtifact from './compact_artifacts/TokenTransferProxy.json';
-import * as ZRXArtifact from './compact_artifacts/ZRX.json';
-import { Artifact } from './types';
-
-export const artifacts = {
-    ZRXArtifact: (ZRXArtifact as any) as Artifact,
-    DummyTokenArtifact: (DummyTokenArtifact as any) as Artifact,
-    TokenArtifact: (TokenArtifact as any) as Artifact,
-    ExchangeArtifact: (ExchangeArtifact as any) as Artifact,
-    EtherTokenArtifact: (EtherTokenArtifact as any) as Artifact,
-    TokenRegistryArtifact: (TokenRegistryArtifact as any) as Artifact,
-    TokenTransferProxyArtifact: (TokenTransferProxyArtifact as any) as Artifact,
-};
diff --git a/packages/0x.js/src/contract_wrappers/contract_wrapper.ts b/packages/0x.js/src/contract_wrappers/contract_wrapper.ts
deleted file mode 100644
index 02be2dab3..000000000
--- a/packages/0x.js/src/contract_wrappers/contract_wrapper.ts
+++ /dev/null
@@ -1,202 +0,0 @@
-import { BlockParamLiteral, ContractAbi, FilterObject, LogEntry, LogWithDecodedArgs, RawLog } from '@0xproject/types';
-import { AbiDecoder, intervalUtils } from '@0xproject/utils';
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
-import { Block, BlockAndLogStreamer } from 'ethereumjs-blockstream';
-import * as _ from 'lodash';
-import * as Web3 from 'web3';
-
-import {
-    Artifact,
-    BlockRange,
-    ContractEventArgs,
-    ContractEvents,
-    EventCallback,
-    IndexedFilterValues,
-    InternalZeroExError,
-    ZeroExError,
-} from '../types';
-import { constants } from '../utils/constants';
-import { filterUtils } from '../utils/filter_utils';
-
-const CONTRACT_NAME_TO_NOT_FOUND_ERROR: {
-    [contractName: string]: ZeroExError;
-} = {
-    ZRX: ZeroExError.ZRXContractDoesNotExist,
-    EtherToken: ZeroExError.EtherTokenContractDoesNotExist,
-    Token: ZeroExError.TokenContractDoesNotExist,
-    TokenRegistry: ZeroExError.TokenRegistryContractDoesNotExist,
-    TokenTransferProxy: ZeroExError.TokenTransferProxyContractDoesNotExist,
-    Exchange: ZeroExError.ExchangeContractDoesNotExist,
-};
-
-export class ContractWrapper {
-    protected _web3Wrapper: Web3Wrapper;
-    protected _networkId: number;
-    private _blockAndLogStreamerIfExists?: BlockAndLogStreamer;
-    private _blockAndLogStreamIntervalIfExists?: NodeJS.Timer;
-    private _filters: { [filterToken: string]: FilterObject };
-    private _filterCallbacks: {
-        [filterToken: string]: EventCallback<ContractEventArgs>;
-    };
-    private _onLogAddedSubscriptionToken: string | undefined;
-    private _onLogRemovedSubscriptionToken: string | undefined;
-    constructor(web3Wrapper: Web3Wrapper, networkId: number) {
-        this._web3Wrapper = web3Wrapper;
-        this._networkId = networkId;
-        this._filters = {};
-        this._filterCallbacks = {};
-        this._blockAndLogStreamerIfExists = undefined;
-        this._onLogAddedSubscriptionToken = undefined;
-        this._onLogRemovedSubscriptionToken = undefined;
-    }
-    protected _unsubscribeAll(): void {
-        const filterTokens = _.keys(this._filterCallbacks);
-        _.each(filterTokens, filterToken => {
-            this._unsubscribe(filterToken);
-        });
-    }
-    protected _unsubscribe(filterToken: string, err?: Error): void {
-        if (_.isUndefined(this._filters[filterToken])) {
-            throw new Error(ZeroExError.SubscriptionNotFound);
-        }
-        if (!_.isUndefined(err)) {
-            const callback = this._filterCallbacks[filterToken];
-            callback(err, undefined);
-        }
-        delete this._filters[filterToken];
-        delete this._filterCallbacks[filterToken];
-        if (_.isEmpty(this._filters)) {
-            this._stopBlockAndLogStream();
-        }
-    }
-    protected _subscribe<ArgsType extends ContractEventArgs>(
-        address: string,
-        eventName: ContractEvents,
-        indexFilterValues: IndexedFilterValues,
-        abi: ContractAbi,
-        callback: EventCallback<ArgsType>,
-    ): string {
-        const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi);
-        if (_.isUndefined(this._blockAndLogStreamerIfExists)) {
-            this._startBlockAndLogStream();
-        }
-        const filterToken = filterUtils.generateUUID();
-        this._filters[filterToken] = filter;
-        this._filterCallbacks[filterToken] = callback as EventCallback<ContractEventArgs>;
-        return filterToken;
-    }
-    protected async _getLogsAsync<ArgsType extends ContractEventArgs>(
-        address: string,
-        eventName: ContractEvents,
-        blockRange: BlockRange,
-        indexFilterValues: IndexedFilterValues,
-        abi: ContractAbi,
-    ): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
-        const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi, blockRange);
-        const logs = await this._web3Wrapper.getLogsAsync(filter);
-        const logsWithDecodedArguments = _.map(logs, this._tryToDecodeLogOrNoop.bind(this));
-        return logsWithDecodedArguments;
-    }
-    protected _tryToDecodeLogOrNoop<ArgsType extends ContractEventArgs>(
-        log: LogEntry,
-    ): LogWithDecodedArgs<ArgsType> | RawLog {
-        if (_.isUndefined(this._web3Wrapper.abiDecoder)) {
-            throw new Error(InternalZeroExError.NoAbiDecoder);
-        }
-        const logWithDecodedArgs = this._web3Wrapper.abiDecoder.tryToDecodeLogOrNoop(log);
-        return logWithDecodedArgs;
-    }
-    protected async _getContractAbiAndAddressFromArtifactsAsync(
-        artifact: Artifact,
-        addressIfExists?: string,
-    ): Promise<[ContractAbi, string]> {
-        let contractAddress: string;
-        if (_.isUndefined(addressIfExists)) {
-            if (_.isUndefined(artifact.networks[this._networkId])) {
-                throw new Error(ZeroExError.ContractNotDeployedOnNetwork);
-            }
-            contractAddress = artifact.networks[this._networkId].address.toLowerCase();
-        } else {
-            contractAddress = addressIfExists;
-        }
-        const doesContractExist = await this._web3Wrapper.doesContractExistAtAddressAsync(contractAddress);
-        if (!doesContractExist) {
-            throw new Error(CONTRACT_NAME_TO_NOT_FOUND_ERROR[artifact.contract_name]);
-        }
-        const abiAndAddress: [ContractAbi, string] = [artifact.abi, contractAddress];
-        return abiAndAddress;
-    }
-    protected _getContractAddress(artifact: Artifact, addressIfExists?: string): string {
-        if (_.isUndefined(addressIfExists)) {
-            const contractAddress = artifact.networks[this._networkId].address;
-            if (_.isUndefined(contractAddress)) {
-                throw new Error(ZeroExError.ExchangeContractDoesNotExist);
-            }
-            return contractAddress;
-        } else {
-            return addressIfExists;
-        }
-    }
-    private _onLogStateChanged<ArgsType extends ContractEventArgs>(isRemoved: boolean, log: LogEntry): void {
-        _.forEach(this._filters, (filter: FilterObject, filterToken: string) => {
-            if (filterUtils.matchesFilter(log, filter)) {
-                const decodedLog = this._tryToDecodeLogOrNoop(log) as LogWithDecodedArgs<ArgsType>;
-                const logEvent = {
-                    log: decodedLog,
-                    isRemoved,
-                };
-                this._filterCallbacks[filterToken](null, logEvent);
-            }
-        });
-    }
-    private _startBlockAndLogStream(): void {
-        if (!_.isUndefined(this._blockAndLogStreamerIfExists)) {
-            throw new Error(ZeroExError.SubscriptionAlreadyPresent);
-        }
-        this._blockAndLogStreamerIfExists = new BlockAndLogStreamer(
-            this._web3Wrapper.getBlockAsync.bind(this._web3Wrapper),
-            this._web3Wrapper.getLogsAsync.bind(this._web3Wrapper),
-        );
-        const catchAllLogFilter = {};
-        this._blockAndLogStreamerIfExists.addLogFilter(catchAllLogFilter);
-        this._blockAndLogStreamIntervalIfExists = intervalUtils.setAsyncExcludingInterval(
-            this._reconcileBlockAsync.bind(this),
-            constants.DEFAULT_BLOCK_POLLING_INTERVAL,
-            this._onReconcileBlockError.bind(this),
-        );
-        let isRemoved = false;
-        this._onLogAddedSubscriptionToken = this._blockAndLogStreamerIfExists.subscribeToOnLogAdded(
-            this._onLogStateChanged.bind(this, isRemoved),
-        );
-        isRemoved = true;
-        this._onLogRemovedSubscriptionToken = this._blockAndLogStreamerIfExists.subscribeToOnLogRemoved(
-            this._onLogStateChanged.bind(this, isRemoved),
-        );
-    }
-    private _onReconcileBlockError(err: Error): void {
-        const filterTokens = _.keys(this._filterCallbacks);
-        _.each(filterTokens, filterToken => {
-            this._unsubscribe(filterToken, err);
-        });
-    }
-    private _setNetworkId(networkId: number): void {
-        this._networkId = networkId;
-    }
-    private _stopBlockAndLogStream(): void {
-        if (_.isUndefined(this._blockAndLogStreamerIfExists)) {
-            throw new Error(ZeroExError.SubscriptionNotFound);
-        }
-        this._blockAndLogStreamerIfExists.unsubscribeFromOnLogAdded(this._onLogAddedSubscriptionToken as string);
-        this._blockAndLogStreamerIfExists.unsubscribeFromOnLogRemoved(this._onLogRemovedSubscriptionToken as string);
-        intervalUtils.clearAsyncExcludingInterval(this._blockAndLogStreamIntervalIfExists as NodeJS.Timer);
-        delete this._blockAndLogStreamerIfExists;
-    }
-    private async _reconcileBlockAsync(): Promise<void> {
-        const latestBlock = await this._web3Wrapper.getBlockAsync(BlockParamLiteral.Latest);
-        // We need to coerce to Block type cause Web3.Block includes types for mempool blocks
-        if (!_.isUndefined(this._blockAndLogStreamerIfExists)) {
-            // If we clear the interval while fetching the block - this._blockAndLogStreamer will be undefined
-            await this._blockAndLogStreamerIfExists.reconcileNewBlock((latestBlock as any) as Block);
-        }
-    }
-}
diff --git a/packages/0x.js/src/contract_wrappers/ether_token_wrapper.ts b/packages/0x.js/src/contract_wrappers/ether_token_wrapper.ts
deleted file mode 100644
index fd39de34b..000000000
--- a/packages/0x.js/src/contract_wrappers/ether_token_wrapper.ts
+++ /dev/null
@@ -1,204 +0,0 @@
-import { schemas } from '@0xproject/json-schemas';
-import { LogWithDecodedArgs } from '@0xproject/types';
-import { AbiDecoder, BigNumber } from '@0xproject/utils';
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
-import * as _ from 'lodash';
-
-import { artifacts } from '../artifacts';
-import { BlockRange, EventCallback, IndexedFilterValues, TransactionOpts, ZeroExError } from '../types';
-import { assert } from '../utils/assert';
-
-import { ContractWrapper } from './contract_wrapper';
-import { EtherTokenContract, EtherTokenContractEventArgs, EtherTokenEvents } from './generated/ether_token';
-import { TokenWrapper } from './token_wrapper';
-
-/**
- * This class includes all the functionality related to interacting with a wrapped Ether ERC20 token contract.
- * The caller can convert ETH into the equivalent number of wrapped ETH ERC20 tokens and back.
- */
-export class EtherTokenWrapper extends ContractWrapper {
-    private _etherTokenContractsByAddress: {
-        [address: string]: EtherTokenContract;
-    } = {};
-    private _tokenWrapper: TokenWrapper;
-    constructor(web3Wrapper: Web3Wrapper, networkId: number, tokenWrapper: TokenWrapper) {
-        super(web3Wrapper, networkId);
-        this._tokenWrapper = tokenWrapper;
-    }
-    /**
-     * Deposit ETH into the Wrapped ETH smart contract and issues the equivalent number of wrapped ETH tokens
-     * to the depositor address. These wrapped ETH tokens can be used in 0x trades and are redeemable for 1-to-1
-     * for ETH.
-     * @param   etherTokenAddress   EtherToken address you wish to deposit into.
-     * @param   amountInWei         Amount of ETH in Wei the caller wishes to deposit.
-     * @param   depositor           The hex encoded user Ethereum address that would like to make the deposit.
-     * @param   txOpts              Transaction parameters.
-     * @return Transaction hash.
-     */
-    public async depositAsync(
-        etherTokenAddress: string,
-        amountInWei: BigNumber,
-        depositor: string,
-        txOpts: TransactionOpts = {},
-    ): Promise<string> {
-        assert.isETHAddressHex('etherTokenAddress', etherTokenAddress);
-        assert.isValidBaseUnitAmount('amountInWei', amountInWei);
-        await assert.isSenderAddressAsync('depositor', depositor, this._web3Wrapper);
-        const normalizedEtherTokenAddress = etherTokenAddress.toLowerCase();
-        const normalizedDepositorAddress = depositor.toLowerCase();
-
-        const ethBalanceInWei = await this._web3Wrapper.getBalanceInWeiAsync(normalizedDepositorAddress);
-        assert.assert(ethBalanceInWei.gte(amountInWei), ZeroExError.InsufficientEthBalanceForDeposit);
-
-        const wethContract = await this._getEtherTokenContractAsync(normalizedEtherTokenAddress);
-        const txHash = await wethContract.deposit.sendTransactionAsync({
-            from: normalizedDepositorAddress,
-            value: amountInWei,
-            gas: txOpts.gasLimit,
-            gasPrice: txOpts.gasPrice,
-        });
-        return txHash;
-    }
-    /**
-     * Withdraw ETH to the withdrawer's address from the wrapped ETH smart contract in exchange for the
-     * equivalent number of wrapped ETH tokens.
-     * @param   etherTokenAddress   EtherToken address you wish to withdraw from.
-     * @param   amountInWei  Amount of ETH in Wei the caller wishes to withdraw.
-     * @param   withdrawer   The hex encoded user Ethereum address that would like to make the withdrawal.
-     * @param   txOpts       Transaction parameters.
-     * @return Transaction hash.
-     */
-    public async withdrawAsync(
-        etherTokenAddress: string,
-        amountInWei: BigNumber,
-        withdrawer: string,
-        txOpts: TransactionOpts = {},
-    ): Promise<string> {
-        assert.isValidBaseUnitAmount('amountInWei', amountInWei);
-        assert.isETHAddressHex('etherTokenAddress', etherTokenAddress);
-        await assert.isSenderAddressAsync('withdrawer', withdrawer, this._web3Wrapper);
-        const normalizedEtherTokenAddress = etherTokenAddress.toLowerCase();
-        const normalizedWithdrawerAddress = withdrawer.toLowerCase();
-
-        const WETHBalanceInBaseUnits = await this._tokenWrapper.getBalanceAsync(
-            normalizedEtherTokenAddress,
-            normalizedWithdrawerAddress,
-        );
-        assert.assert(WETHBalanceInBaseUnits.gte(amountInWei), ZeroExError.InsufficientWEthBalanceForWithdrawal);
-
-        const wethContract = await this._getEtherTokenContractAsync(normalizedEtherTokenAddress);
-        const txHash = await wethContract.withdraw.sendTransactionAsync(amountInWei, {
-            from: normalizedWithdrawerAddress,
-            gas: txOpts.gasLimit,
-            gasPrice: txOpts.gasPrice,
-        });
-        return txHash;
-    }
-    /**
-     * Gets historical logs without creating a subscription
-     * @param   etherTokenAddress   An address of the ether token that emitted the logs.
-     * @param   eventName           The ether token contract event you would like to subscribe to.
-     * @param   blockRange          Block range to get logs from.
-     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
-     *                              the value is the value you are interested in. E.g `{_owner: aUserAddressHex}`
-     * @return  Array of logs that match the parameters
-     */
-    public async getLogsAsync<ArgsType extends EtherTokenContractEventArgs>(
-        etherTokenAddress: string,
-        eventName: EtherTokenEvents,
-        blockRange: BlockRange,
-        indexFilterValues: IndexedFilterValues,
-    ): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
-        assert.isETHAddressHex('etherTokenAddress', etherTokenAddress);
-        const normalizedEtherTokenAddress = etherTokenAddress.toLowerCase();
-        assert.doesBelongToStringEnum('eventName', eventName, EtherTokenEvents);
-        assert.doesConformToSchema('blockRange', blockRange, schemas.blockRangeSchema);
-        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
-        const logs = await this._getLogsAsync<ArgsType>(
-            normalizedEtherTokenAddress,
-            eventName,
-            blockRange,
-            indexFilterValues,
-            artifacts.EtherTokenArtifact.abi,
-        );
-        return logs;
-    }
-    /**
-     * Subscribe to an event type emitted by the Token contract.
-     * @param   etherTokenAddress   The hex encoded address where the ether token is deployed.
-     * @param   eventName           The ether token contract event you would like to subscribe to.
-     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
-     *                              the value is the value you are interested in. E.g `{_owner: aUserAddressHex}`
-     * @param   callback            Callback that gets called when a log is added/removed
-     * @return Subscription token used later to unsubscribe
-     */
-    public subscribe<ArgsType extends EtherTokenContractEventArgs>(
-        etherTokenAddress: string,
-        eventName: EtherTokenEvents,
-        indexFilterValues: IndexedFilterValues,
-        callback: EventCallback<ArgsType>,
-    ): string {
-        assert.isETHAddressHex('etherTokenAddress', etherTokenAddress);
-        const normalizedEtherTokenAddress = etherTokenAddress.toLowerCase();
-        assert.doesBelongToStringEnum('eventName', eventName, EtherTokenEvents);
-        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
-        assert.isFunction('callback', callback);
-        const subscriptionToken = this._subscribe<ArgsType>(
-            normalizedEtherTokenAddress,
-            eventName,
-            indexFilterValues,
-            artifacts.EtherTokenArtifact.abi,
-            callback,
-        );
-        return subscriptionToken;
-    }
-    /**
-     * Cancel a subscription
-     * @param   subscriptionToken Subscription token returned by `subscribe()`
-     */
-    public unsubscribe(subscriptionToken: string): void {
-        this._unsubscribe(subscriptionToken);
-    }
-    /**
-     * Cancels all existing subscriptions
-     */
-    public unsubscribeAll(): void {
-        super._unsubscribeAll();
-    }
-    /**
-     * Retrieves the Ethereum address of the EtherToken contract deployed on the network
-     * that the user-passed web3 provider is connected to. If it's not Kovan, Ropsten, Rinkeby, Mainnet or TestRPC
-     * (networkId: 50), it will return undefined (e.g a private network).
-     * @returns The Ethereum address of the EtherToken contract or undefined.
-     */
-    public getContractAddressIfExists(): string | undefined {
-        const networkSpecificArtifact = artifacts.EtherTokenArtifact.networks[this._networkId];
-        const contractAddressIfExists = _.isUndefined(networkSpecificArtifact)
-            ? undefined
-            : networkSpecificArtifact.address;
-        return contractAddressIfExists;
-    }
-    private _invalidateContractInstance(): void {
-        this.unsubscribeAll();
-        this._etherTokenContractsByAddress = {};
-    }
-    private async _getEtherTokenContractAsync(etherTokenAddress: string): Promise<EtherTokenContract> {
-        let etherTokenContract = this._etherTokenContractsByAddress[etherTokenAddress];
-        if (!_.isUndefined(etherTokenContract)) {
-            return etherTokenContract;
-        }
-        const [abi, address] = await this._getContractAbiAndAddressFromArtifactsAsync(
-            artifacts.EtherTokenArtifact,
-            etherTokenAddress,
-        );
-        const contractInstance = new EtherTokenContract(
-            abi,
-            address,
-            this._web3Wrapper.getProvider(),
-            this._web3Wrapper.getContractDefaults(),
-        );
-        etherTokenContract = contractInstance;
-        this._etherTokenContractsByAddress[etherTokenAddress] = etherTokenContract;
-        return etherTokenContract;
-    }
-}
diff --git a/packages/0x.js/src/contract_wrappers/exchange_wrapper.ts b/packages/0x.js/src/contract_wrappers/exchange_wrapper.ts
deleted file mode 100644
index 6ddaaaf4f..000000000
--- a/packages/0x.js/src/contract_wrappers/exchange_wrapper.ts
+++ /dev/null
@@ -1,964 +0,0 @@
-import { schemas } from '@0xproject/json-schemas';
-import { getOrderHashHex } from '@0xproject/order-utils';
-import {
-    BlockParamLiteral,
-    DecodedLogArgs,
-    ECSignature,
-    LogEntry,
-    LogWithDecodedArgs,
-    Order,
-    SignedOrder,
-} from '@0xproject/types';
-import { AbiDecoder, BigNumber } from '@0xproject/utils';
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
-import * as _ from 'lodash';
-
-import { artifacts } from '../artifacts';
-import { SimpleBalanceAndProxyAllowanceFetcher } from '../fetchers/simple_balance_and_proxy_allowance_fetcher';
-import { SimpleOrderFilledCancelledFetcher } from '../fetchers/simple_order_filled_cancelled_fetcher';
-import {
-    BlockRange,
-    EventCallback,
-    ExchangeContractErrCodes,
-    ExchangeContractErrs,
-    IndexedFilterValues,
-    MethodOpts,
-    OrderAddresses,
-    OrderCancellationRequest,
-    OrderFillRequest,
-    OrderState,
-    OrderTransactionOpts,
-    OrderValues,
-    ValidateOrderFillableOpts,
-} from '../types';
-import { assert } from '../utils/assert';
-import { decorators } from '../utils/decorators';
-import { ExchangeTransferSimulator } from '../utils/exchange_transfer_simulator';
-import { OrderStateUtils } from '../utils/order_state_utils';
-import { OrderValidationUtils } from '../utils/order_validation_utils';
-import { utils } from '../utils/utils';
-
-import { ContractWrapper } from './contract_wrapper';
-import {
-    ExchangeContract,
-    ExchangeContractEventArgs,
-    ExchangeEvents,
-    LogErrorContractEventArgs,
-} from './generated/exchange';
-import { TokenWrapper } from './token_wrapper';
-const SHOULD_VALIDATE_BY_DEFAULT = true;
-
-interface ExchangeContractErrCodesToMsgs {
-    [exchangeContractErrCodes: number]: string;
-}
-
-/**
- * This class includes all the functionality related to calling methods and subscribing to
- * events of the 0x Exchange smart contract.
- */
-export class ExchangeWrapper extends ContractWrapper {
-    private _exchangeContractIfExists?: ExchangeContract;
-    private _orderValidationUtils: OrderValidationUtils;
-    private _tokenWrapper: TokenWrapper;
-    private _exchangeContractErrCodesToMsg: ExchangeContractErrCodesToMsgs = {
-        [ExchangeContractErrCodes.ERROR_FILL_EXPIRED]: ExchangeContractErrs.OrderFillExpired,
-        [ExchangeContractErrCodes.ERROR_CANCEL_EXPIRED]: ExchangeContractErrs.OrderFillExpired,
-        [ExchangeContractErrCodes.ERROR_FILL_NO_VALUE]: ExchangeContractErrs.OrderRemainingFillAmountZero,
-        [ExchangeContractErrCodes.ERROR_CANCEL_NO_VALUE]: ExchangeContractErrs.OrderRemainingFillAmountZero,
-        [ExchangeContractErrCodes.ERROR_FILL_TRUNCATION]: ExchangeContractErrs.OrderFillRoundingError,
-        [ExchangeContractErrCodes.ERROR_FILL_BALANCE_ALLOWANCE]: ExchangeContractErrs.FillBalanceAllowanceError,
-    };
-    private _contractAddressIfExists?: string;
-    private _zrxContractAddressIfExists?: string;
-    private static _getOrderAddressesAndValues(order: Order): [OrderAddresses, OrderValues] {
-        const orderAddresses: OrderAddresses = [
-            order.maker,
-            order.taker,
-            order.makerTokenAddress,
-            order.takerTokenAddress,
-            order.feeRecipient,
-        ];
-        const orderValues: OrderValues = [
-            order.makerTokenAmount,
-            order.takerTokenAmount,
-            order.makerFee,
-            order.takerFee,
-            order.expirationUnixTimestampSec,
-            order.salt,
-        ];
-        return [orderAddresses, orderValues];
-    }
-    constructor(
-        web3Wrapper: Web3Wrapper,
-        networkId: number,
-        tokenWrapper: TokenWrapper,
-        contractAddressIfExists?: string,
-        zrxContractAddressIfExists?: string,
-    ) {
-        super(web3Wrapper, networkId);
-        this._tokenWrapper = tokenWrapper;
-        this._orderValidationUtils = new OrderValidationUtils(this);
-        this._contractAddressIfExists = contractAddressIfExists;
-        this._zrxContractAddressIfExists = zrxContractAddressIfExists;
-    }
-    /**
-     * Returns the unavailable takerAmount of an order. Unavailable amount is defined as the total
-     * amount that has been filled or cancelled. The remaining takerAmount can be calculated by
-     * subtracting the unavailable amount from the total order takerAmount.
-     * @param   orderHash               The hex encoded orderHash for which you would like to retrieve the
-     *                                  unavailable takerAmount.
-     * @param   methodOpts              Optional arguments this method accepts.
-     * @return  The amount of the order (in taker tokens) that has either been filled or cancelled.
-     */
-    public async getUnavailableTakerAmountAsync(orderHash: string, methodOpts?: MethodOpts): Promise<BigNumber> {
-        assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
-
-        const exchangeContract = await this._getExchangeContractAsync();
-        const defaultBlock = _.isUndefined(methodOpts) ? undefined : methodOpts.defaultBlock;
-        const txData = {};
-        let unavailableTakerTokenAmount = await exchangeContract.getUnavailableTakerTokenAmount.callAsync(
-            orderHash,
-            txData,
-            defaultBlock,
-        );
-        // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
-        unavailableTakerTokenAmount = new BigNumber(unavailableTakerTokenAmount);
-        return unavailableTakerTokenAmount;
-    }
-    /**
-     * Retrieve the takerAmount of an order that has already been filled.
-     * @param   orderHash    The hex encoded orderHash for which you would like to retrieve the filled takerAmount.
-     * @param   methodOpts   Optional arguments this method accepts.
-     * @return  The amount of the order (in taker tokens) that has already been filled.
-     */
-    public async getFilledTakerAmountAsync(orderHash: string, methodOpts?: MethodOpts): Promise<BigNumber> {
-        assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
-
-        const exchangeContract = await this._getExchangeContractAsync();
-        const defaultBlock = _.isUndefined(methodOpts) ? undefined : methodOpts.defaultBlock;
-        const txData = {};
-        let fillAmountInBaseUnits = await exchangeContract.filled.callAsync(orderHash, txData, defaultBlock);
-        // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
-        fillAmountInBaseUnits = new BigNumber(fillAmountInBaseUnits);
-        return fillAmountInBaseUnits;
-    }
-    /**
-     * Retrieve the takerAmount of an order that has been cancelled.
-     * @param   orderHash    The hex encoded orderHash for which you would like to retrieve the
-     *                       cancelled takerAmount.
-     * @param   methodOpts   Optional arguments this method accepts.
-     * @return  The amount of the order (in taker tokens) that has been cancelled.
-     */
-    public async getCancelledTakerAmountAsync(orderHash: string, methodOpts?: MethodOpts): Promise<BigNumber> {
-        assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
-
-        const exchangeContract = await this._getExchangeContractAsync();
-        const defaultBlock = _.isUndefined(methodOpts) ? undefined : methodOpts.defaultBlock;
-        const txData = {};
-        let cancelledAmountInBaseUnits = await exchangeContract.cancelled.callAsync(orderHash, txData, defaultBlock);
-        // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
-        cancelledAmountInBaseUnits = new BigNumber(cancelledAmountInBaseUnits);
-        return cancelledAmountInBaseUnits;
-    }
-    /**
-     * Fills a signed order with an amount denominated in baseUnits of the taker token.
-     * Since the order in which transactions are included in the next block is indeterminate, race-conditions
-     * could arise where a users balance or allowance changes before the fillOrder executes. Because of this,
-     * we allow you to specify `shouldThrowOnInsufficientBalanceOrAllowance`.
-     * If false, the smart contract will not throw if the parties
-     * do not have sufficient balances/allowances, preserving gas costs. Setting it to true forgoes this check
-     * and causes the smart contract to throw (using all the gas supplied) instead.
-     * @param   signedOrder                                 An object that conforms to the SignedOrder interface.
-     * @param   fillTakerTokenAmount                        The amount of the order (in taker tokens baseUnits) that
-     *                                                      you wish to fill.
-     * @param   shouldThrowOnInsufficientBalanceOrAllowance Whether or not you wish for the contract call to throw
-     *                                                      if upon execution the tokens cannot be transferred.
-     * @param   takerAddress                                The user Ethereum address who would like to fill this order.
-     *                                                      Must be available via the supplied Provider
-     *                                                      passed to 0x.js.
-     * @param   orderTransactionOpts                        Optional arguments this method accepts.
-     * @return  Transaction hash.
-     */
-    @decorators.asyncZeroExErrorHandler
-    public async fillOrderAsync(
-        signedOrder: SignedOrder,
-        fillTakerTokenAmount: BigNumber,
-        shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-        takerAddress: string,
-        orderTransactionOpts: OrderTransactionOpts = {},
-    ): Promise<string> {
-        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
-        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
-        assert.isBoolean('shouldThrowOnInsufficientBalanceOrAllowance', shouldThrowOnInsufficientBalanceOrAllowance);
-        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
-        const normalizedTakerAddress = takerAddress.toLowerCase();
-
-        const exchangeInstance = await this._getExchangeContractAsync();
-        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate)
-            ? SHOULD_VALIDATE_BY_DEFAULT
-            : orderTransactionOpts.shouldValidate;
-        if (shouldValidate) {
-            const zrxTokenAddress = this.getZRXTokenAddress();
-            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
-            await this._orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
-                exchangeTradeEmulator,
-                signedOrder,
-                fillTakerTokenAmount,
-                normalizedTakerAddress,
-                zrxTokenAddress,
-            );
-        }
-
-        const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(signedOrder);
-
-        const txHash: string = await exchangeInstance.fillOrder.sendTransactionAsync(
-            orderAddresses,
-            orderValues,
-            fillTakerTokenAmount,
-            shouldThrowOnInsufficientBalanceOrAllowance,
-            signedOrder.ecSignature.v,
-            signedOrder.ecSignature.r,
-            signedOrder.ecSignature.s,
-            {
-                from: normalizedTakerAddress,
-                gas: orderTransactionOpts.gasLimit,
-                gasPrice: orderTransactionOpts.gasPrice,
-            },
-        );
-        return txHash;
-    }
-    /**
-     * Sequentially and atomically fills signedOrders up to the specified takerTokenFillAmount.
-     * If the fill amount is reached - it succeeds and does not fill the rest of the orders.
-     * If fill amount is not reached - it fills as much of the fill amount as possible and succeeds.
-     * @param   signedOrders                                The array of signedOrders that you would like to fill until
-     *                                                      takerTokenFillAmount is reached.
-     * @param   fillTakerTokenAmount                        The total amount of the takerTokens you would like to fill.
-     * @param   shouldThrowOnInsufficientBalanceOrAllowance Whether or not you wish for the contract call to throw if
-     *                                                      upon execution any of the tokens cannot be transferred.
-     *                                                      If set to false, the call will continue to fill subsequent
-     *                                                      signedOrders even when some cannot be filled.
-     * @param   takerAddress                                The user Ethereum address who would like to fill these
-     *                                                      orders. Must be available via the supplied Provider
-     *                                                      passed to 0x.js.
-     * @param   orderTransactionOpts                        Optional arguments this method accepts.
-     * @return  Transaction hash.
-     */
-    @decorators.asyncZeroExErrorHandler
-    public async fillOrdersUpToAsync(
-        signedOrders: SignedOrder[],
-        fillTakerTokenAmount: BigNumber,
-        shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-        takerAddress: string,
-        orderTransactionOpts: OrderTransactionOpts = {},
-    ): Promise<string> {
-        assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
-        const takerTokenAddresses = _.map(signedOrders, signedOrder => signedOrder.takerTokenAddress);
-        assert.hasAtMostOneUniqueValue(
-            takerTokenAddresses,
-            ExchangeContractErrs.MultipleTakerTokensInFillUpToDisallowed,
-        );
-        const exchangeContractAddresses = _.map(signedOrders, signedOrder => signedOrder.exchangeContractAddress);
-        assert.hasAtMostOneUniqueValue(
-            exchangeContractAddresses,
-            ExchangeContractErrs.BatchOrdersMustHaveSameExchangeAddress,
-        );
-        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
-        assert.isBoolean('shouldThrowOnInsufficientBalanceOrAllowance', shouldThrowOnInsufficientBalanceOrAllowance);
-        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
-        const normalizedTakerAddress = takerAddress.toLowerCase();
-
-        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate)
-            ? SHOULD_VALIDATE_BY_DEFAULT
-            : orderTransactionOpts.shouldValidate;
-        if (shouldValidate) {
-            let filledTakerTokenAmount = new BigNumber(0);
-            const zrxTokenAddress = this.getZRXTokenAddress();
-            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
-            for (const signedOrder of signedOrders) {
-                const singleFilledTakerTokenAmount = await this._orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
-                    exchangeTradeEmulator,
-                    signedOrder,
-                    fillTakerTokenAmount.minus(filledTakerTokenAmount),
-                    normalizedTakerAddress,
-                    zrxTokenAddress,
-                );
-                filledTakerTokenAmount = filledTakerTokenAmount.plus(singleFilledTakerTokenAmount);
-                if (filledTakerTokenAmount.eq(fillTakerTokenAmount)) {
-                    break;
-                }
-            }
-        }
-
-        if (_.isEmpty(signedOrders)) {
-            throw new Error(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
-        }
-
-        const orderAddressesValuesAndSignatureArray = _.map(signedOrders, signedOrder => {
-            return [
-                ...ExchangeWrapper._getOrderAddressesAndValues(signedOrder),
-                signedOrder.ecSignature.v,
-                signedOrder.ecSignature.r,
-                signedOrder.ecSignature.s,
-            ];
-        });
-        // We use _.unzip<any> because _.unzip doesn't type check if values have different types :'(
-        const [orderAddressesArray, orderValuesArray, vArray, rArray, sArray] = _.unzip<any>(
-            orderAddressesValuesAndSignatureArray,
-        );
-
-        const exchangeInstance = await this._getExchangeContractAsync();
-        const txHash = await exchangeInstance.fillOrdersUpTo.sendTransactionAsync(
-            orderAddressesArray,
-            orderValuesArray,
-            fillTakerTokenAmount,
-            shouldThrowOnInsufficientBalanceOrAllowance,
-            vArray,
-            rArray,
-            sArray,
-            {
-                from: normalizedTakerAddress,
-                gas: orderTransactionOpts.gasLimit,
-                gasPrice: orderTransactionOpts.gasPrice,
-            },
-        );
-        return txHash;
-    }
-    /**
-     * Batch version of fillOrderAsync.
-     * Executes multiple fills atomically in a single transaction.
-     * If shouldThrowOnInsufficientBalanceOrAllowance is set to false, it will continue filling subsequent orders even
-     * when earlier ones fail.
-     * When shouldThrowOnInsufficientBalanceOrAllowance is set to true, if any fill fails, the entire batch fails.
-     * @param   orderFillRequests                               An array of objects that conform to the
-     *                                                          OrderFillRequest interface.
-     * @param   shouldThrowOnInsufficientBalanceOrAllowance     Whether or not you wish for the contract call to throw
-     *                                                          if upon execution any of the tokens cannot be
-     *                                                          transferred. If set to false, the call will continue to
-     *                                                          fill subsequent signedOrders even when some
-     *                                                          cannot be filled.
-     * @param   takerAddress                                    The user Ethereum address who would like to fill
-     *                                                          these orders. Must be available via the supplied
-     *                                                          Provider passed to 0x.js.
-     * @param   orderTransactionOpts                            Optional arguments this method accepts.
-     * @return  Transaction hash.
-     */
-    @decorators.asyncZeroExErrorHandler
-    public async batchFillOrdersAsync(
-        orderFillRequests: OrderFillRequest[],
-        shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-        takerAddress: string,
-        orderTransactionOpts: OrderTransactionOpts = {},
-    ): Promise<string> {
-        assert.doesConformToSchema('orderFillRequests', orderFillRequests, schemas.orderFillRequestsSchema);
-        const exchangeContractAddresses = _.map(
-            orderFillRequests,
-            orderFillRequest => orderFillRequest.signedOrder.exchangeContractAddress,
-        );
-        assert.hasAtMostOneUniqueValue(
-            exchangeContractAddresses,
-            ExchangeContractErrs.BatchOrdersMustHaveSameExchangeAddress,
-        );
-        assert.isBoolean('shouldThrowOnInsufficientBalanceOrAllowance', shouldThrowOnInsufficientBalanceOrAllowance);
-        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
-        const normalizedTakerAddress = takerAddress.toLowerCase();
-        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate)
-            ? SHOULD_VALIDATE_BY_DEFAULT
-            : orderTransactionOpts.shouldValidate;
-        if (shouldValidate) {
-            const zrxTokenAddress = this.getZRXTokenAddress();
-            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
-            for (const orderFillRequest of orderFillRequests) {
-                await this._orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
-                    exchangeTradeEmulator,
-                    orderFillRequest.signedOrder,
-                    orderFillRequest.takerTokenFillAmount,
-                    normalizedTakerAddress,
-                    zrxTokenAddress,
-                );
-            }
-        }
-        if (_.isEmpty(orderFillRequests)) {
-            throw new Error(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
-        }
-
-        const orderAddressesValuesAmountsAndSignatureArray = _.map(orderFillRequests, orderFillRequest => {
-            return [
-                ...ExchangeWrapper._getOrderAddressesAndValues(orderFillRequest.signedOrder),
-                orderFillRequest.takerTokenFillAmount,
-                orderFillRequest.signedOrder.ecSignature.v,
-                orderFillRequest.signedOrder.ecSignature.r,
-                orderFillRequest.signedOrder.ecSignature.s,
-            ];
-        });
-        // We use _.unzip<any> because _.unzip doesn't type check if values have different types :'(
-        const [orderAddressesArray, orderValuesArray, fillTakerTokenAmounts, vArray, rArray, sArray] = _.unzip<any>(
-            orderAddressesValuesAmountsAndSignatureArray,
-        );
-
-        const exchangeInstance = await this._getExchangeContractAsync();
-        const txHash = await exchangeInstance.batchFillOrders.sendTransactionAsync(
-            orderAddressesArray,
-            orderValuesArray,
-            fillTakerTokenAmounts,
-            shouldThrowOnInsufficientBalanceOrAllowance,
-            vArray,
-            rArray,
-            sArray,
-            {
-                from: normalizedTakerAddress,
-                gas: orderTransactionOpts.gasLimit,
-                gasPrice: orderTransactionOpts.gasPrice,
-            },
-        );
-        return txHash;
-    }
-    /**
-     * Attempts to fill a specific amount of an order. If the entire amount specified cannot be filled,
-     * the fill order is abandoned.
-     * @param   signedOrder             An object that conforms to the SignedOrder interface. The
-     *                                  signedOrder you wish to fill.
-     * @param   fillTakerTokenAmount    The total amount of the takerTokens you would like to fill.
-     * @param   takerAddress            The user Ethereum address who would like to fill this order.
-     *                                  Must be available via the supplied Provider passed to 0x.js.
-     * @param   orderTransactionOpts    Optional arguments this method accepts.
-     * @return  Transaction hash.
-     */
-    @decorators.asyncZeroExErrorHandler
-    public async fillOrKillOrderAsync(
-        signedOrder: SignedOrder,
-        fillTakerTokenAmount: BigNumber,
-        takerAddress: string,
-        orderTransactionOpts: OrderTransactionOpts = {},
-    ): Promise<string> {
-        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
-        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
-        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
-        const normalizedTakerAddress = takerAddress.toLowerCase();
-
-        const exchangeInstance = await this._getExchangeContractAsync();
-
-        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate)
-            ? SHOULD_VALIDATE_BY_DEFAULT
-            : orderTransactionOpts.shouldValidate;
-        if (shouldValidate) {
-            const zrxTokenAddress = this.getZRXTokenAddress();
-            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
-            await this._orderValidationUtils.validateFillOrKillOrderThrowIfInvalidAsync(
-                exchangeTradeEmulator,
-                signedOrder,
-                fillTakerTokenAmount,
-                normalizedTakerAddress,
-                zrxTokenAddress,
-            );
-        }
-
-        const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(signedOrder);
-        const txHash = await exchangeInstance.fillOrKillOrder.sendTransactionAsync(
-            orderAddresses,
-            orderValues,
-            fillTakerTokenAmount,
-            signedOrder.ecSignature.v,
-            signedOrder.ecSignature.r,
-            signedOrder.ecSignature.s,
-            {
-                from: normalizedTakerAddress,
-                gas: orderTransactionOpts.gasLimit,
-                gasPrice: orderTransactionOpts.gasPrice,
-            },
-        );
-        return txHash;
-    }
-    /**
-     * Batch version of fillOrKill. Allows a taker to specify a batch of orders that will either be atomically
-     * filled (each to the specified fillAmount) or aborted.
-     * @param   orderFillRequests           An array of objects that conform to the OrderFillRequest interface.
-     * @param   takerAddress                The user Ethereum address who would like to fill there orders.
-     *                                      Must be available via the supplied Provider passed to 0x.js.
-     * @param   orderTransactionOpts        Optional arguments this method accepts.
-     * @return  Transaction hash.
-     */
-    @decorators.asyncZeroExErrorHandler
-    public async batchFillOrKillAsync(
-        orderFillRequests: OrderFillRequest[],
-        takerAddress: string,
-        orderTransactionOpts: OrderTransactionOpts = {},
-    ): Promise<string> {
-        assert.doesConformToSchema('orderFillRequests', orderFillRequests, schemas.orderFillRequestsSchema);
-        const exchangeContractAddresses = _.map(
-            orderFillRequests,
-            orderFillRequest => orderFillRequest.signedOrder.exchangeContractAddress,
-        );
-        assert.hasAtMostOneUniqueValue(
-            exchangeContractAddresses,
-            ExchangeContractErrs.BatchOrdersMustHaveSameExchangeAddress,
-        );
-        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
-        const normalizedTakerAddress = takerAddress.toLowerCase();
-        if (_.isEmpty(orderFillRequests)) {
-            throw new Error(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
-        }
-        const exchangeInstance = await this._getExchangeContractAsync();
-
-        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate)
-            ? SHOULD_VALIDATE_BY_DEFAULT
-            : orderTransactionOpts.shouldValidate;
-        if (shouldValidate) {
-            const zrxTokenAddress = this.getZRXTokenAddress();
-            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
-            for (const orderFillRequest of orderFillRequests) {
-                await this._orderValidationUtils.validateFillOrKillOrderThrowIfInvalidAsync(
-                    exchangeTradeEmulator,
-                    orderFillRequest.signedOrder,
-                    orderFillRequest.takerTokenFillAmount,
-                    normalizedTakerAddress,
-                    zrxTokenAddress,
-                );
-            }
-        }
-
-        const orderAddressesValuesAndTakerTokenFillAmounts = _.map(orderFillRequests, request => {
-            return [
-                ...ExchangeWrapper._getOrderAddressesAndValues(request.signedOrder),
-                request.takerTokenFillAmount,
-                request.signedOrder.ecSignature.v,
-                request.signedOrder.ecSignature.r,
-                request.signedOrder.ecSignature.s,
-            ];
-        });
-
-        // We use _.unzip<any> because _.unzip doesn't type check if values have different types :'(
-        const [orderAddresses, orderValues, fillTakerTokenAmounts, vParams, rParams, sParams] = _.unzip<any>(
-            orderAddressesValuesAndTakerTokenFillAmounts,
-        );
-        const txHash = await exchangeInstance.batchFillOrKillOrders.sendTransactionAsync(
-            orderAddresses,
-            orderValues,
-            fillTakerTokenAmounts,
-            vParams,
-            rParams,
-            sParams,
-            {
-                from: normalizedTakerAddress,
-                gas: orderTransactionOpts.gasLimit,
-                gasPrice: orderTransactionOpts.gasPrice,
-            },
-        );
-        return txHash;
-    }
-    /**
-     * Cancel a given fill amount of an order. Cancellations are cumulative.
-     * @param   order                   An object that conforms to the Order or SignedOrder interface.
-     *                                  The order you would like to cancel.
-     * @param   cancelTakerTokenAmount  The amount (specified in taker tokens) that you would like to cancel.
-     * @param   transactionOpts         Optional arguments this method accepts.
-     * @return  Transaction hash.
-     */
-    @decorators.asyncZeroExErrorHandler
-    public async cancelOrderAsync(
-        order: Order | SignedOrder,
-        cancelTakerTokenAmount: BigNumber,
-        orderTransactionOpts: OrderTransactionOpts = {},
-    ): Promise<string> {
-        assert.doesConformToSchema('order', order, schemas.orderSchema);
-        assert.isValidBaseUnitAmount('takerTokenCancelAmount', cancelTakerTokenAmount);
-        await assert.isSenderAddressAsync('order.maker', order.maker, this._web3Wrapper);
-        const normalizedMakerAddress = order.maker.toLowerCase();
-
-        const exchangeInstance = await this._getExchangeContractAsync();
-
-        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate)
-            ? SHOULD_VALIDATE_BY_DEFAULT
-            : orderTransactionOpts.shouldValidate;
-        if (shouldValidate) {
-            const orderHash = getOrderHashHex(order);
-            const unavailableTakerTokenAmount = await this.getUnavailableTakerAmountAsync(orderHash);
-            OrderValidationUtils.validateCancelOrderThrowIfInvalid(
-                order,
-                cancelTakerTokenAmount,
-                unavailableTakerTokenAmount,
-            );
-        }
-
-        const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(order);
-        const txHash = await exchangeInstance.cancelOrder.sendTransactionAsync(
-            orderAddresses,
-            orderValues,
-            cancelTakerTokenAmount,
-            {
-                from: normalizedMakerAddress,
-                gas: orderTransactionOpts.gasLimit,
-                gasPrice: orderTransactionOpts.gasPrice,
-            },
-        );
-        return txHash;
-    }
-    /**
-     * Batch version of cancelOrderAsync. Atomically cancels multiple orders in a single transaction.
-     * All orders must be from the same maker.
-     * @param   orderCancellationRequests   An array of objects that conform to the OrderCancellationRequest
-     *                                      interface.
-     * @param   transactionOpts             Optional arguments this method accepts.
-     * @return  Transaction hash.
-     */
-    @decorators.asyncZeroExErrorHandler
-    public async batchCancelOrdersAsync(
-        orderCancellationRequests: OrderCancellationRequest[],
-        orderTransactionOpts: OrderTransactionOpts = {},
-    ): Promise<string> {
-        assert.doesConformToSchema(
-            'orderCancellationRequests',
-            orderCancellationRequests,
-            schemas.orderCancellationRequestsSchema,
-        );
-        const exchangeContractAddresses = _.map(
-            orderCancellationRequests,
-            orderCancellationRequest => orderCancellationRequest.order.exchangeContractAddress,
-        );
-        assert.hasAtMostOneUniqueValue(
-            exchangeContractAddresses,
-            ExchangeContractErrs.BatchOrdersMustHaveSameExchangeAddress,
-        );
-        const makers = _.map(orderCancellationRequests, cancellationRequest => cancellationRequest.order.maker);
-        assert.hasAtMostOneUniqueValue(makers, ExchangeContractErrs.MultipleMakersInSingleCancelBatchDisallowed);
-        const maker = makers[0];
-        await assert.isSenderAddressAsync('maker', maker, this._web3Wrapper);
-        const normalizedMakerAddress = maker.toLowerCase();
-
-        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate)
-            ? SHOULD_VALIDATE_BY_DEFAULT
-            : orderTransactionOpts.shouldValidate;
-        if (shouldValidate) {
-            for (const orderCancellationRequest of orderCancellationRequests) {
-                const orderHash = getOrderHashHex(orderCancellationRequest.order);
-                const unavailableTakerTokenAmount = await this.getUnavailableTakerAmountAsync(orderHash);
-                OrderValidationUtils.validateCancelOrderThrowIfInvalid(
-                    orderCancellationRequest.order,
-                    orderCancellationRequest.takerTokenCancelAmount,
-                    unavailableTakerTokenAmount,
-                );
-            }
-        }
-        if (_.isEmpty(orderCancellationRequests)) {
-            throw new Error(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
-        }
-        const exchangeInstance = await this._getExchangeContractAsync();
-        const orderAddressesValuesAndTakerTokenCancelAmounts = _.map(orderCancellationRequests, cancellationRequest => {
-            return [
-                ...ExchangeWrapper._getOrderAddressesAndValues(cancellationRequest.order),
-                cancellationRequest.takerTokenCancelAmount,
-            ];
-        });
-        // We use _.unzip<any> because _.unzip doesn't type check if values have different types :'(
-        const [orderAddresses, orderValues, cancelTakerTokenAmounts] = _.unzip<any>(
-            orderAddressesValuesAndTakerTokenCancelAmounts,
-        );
-        const txHash = await exchangeInstance.batchCancelOrders.sendTransactionAsync(
-            orderAddresses,
-            orderValues,
-            cancelTakerTokenAmounts,
-            {
-                from: normalizedMakerAddress,
-                gas: orderTransactionOpts.gasLimit,
-                gasPrice: orderTransactionOpts.gasPrice,
-            },
-        );
-        return txHash;
-    }
-    /**
-     * Subscribe to an event type emitted by the Exchange contract.
-     * @param   eventName           The exchange contract event you would like to subscribe to.
-     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
-     *                              the value is the value you are interested in. E.g `{maker: aUserAddressHex}`
-     * @param   callback            Callback that gets called when a log is added/removed
-     * @return Subscription token used later to unsubscribe
-     */
-    public subscribe<ArgsType extends ExchangeContractEventArgs>(
-        eventName: ExchangeEvents,
-        indexFilterValues: IndexedFilterValues,
-        callback: EventCallback<ArgsType>,
-    ): string {
-        assert.doesBelongToStringEnum('eventName', eventName, ExchangeEvents);
-        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
-        assert.isFunction('callback', callback);
-        const exchangeContractAddress = this.getContractAddress();
-        const subscriptionToken = this._subscribe<ArgsType>(
-            exchangeContractAddress,
-            eventName,
-            indexFilterValues,
-            artifacts.ExchangeArtifact.abi,
-            callback,
-        );
-        return subscriptionToken;
-    }
-    /**
-     * Cancel a subscription
-     * @param   subscriptionToken Subscription token returned by `subscribe()`
-     */
-    public unsubscribe(subscriptionToken: string): void {
-        this._unsubscribe(subscriptionToken);
-    }
-    /**
-     * Cancels all existing subscriptions
-     */
-    public unsubscribeAll(): void {
-        super._unsubscribeAll();
-    }
-    /**
-     * Gets historical logs without creating a subscription
-     * @param   eventName           The exchange contract event you would like to subscribe to.
-     * @param   blockRange          Block range to get logs from.
-     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
-     *                              the value is the value you are interested in. E.g `{_from: aUserAddressHex}`
-     * @return  Array of logs that match the parameters
-     */
-    public async getLogsAsync<ArgsType extends ExchangeContractEventArgs>(
-        eventName: ExchangeEvents,
-        blockRange: BlockRange,
-        indexFilterValues: IndexedFilterValues,
-    ): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
-        assert.doesBelongToStringEnum('eventName', eventName, ExchangeEvents);
-        assert.doesConformToSchema('blockRange', blockRange, schemas.blockRangeSchema);
-        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
-        const exchangeContractAddress = this.getContractAddress();
-        const logs = await this._getLogsAsync<ArgsType>(
-            exchangeContractAddress,
-            eventName,
-            blockRange,
-            indexFilterValues,
-            artifacts.ExchangeArtifact.abi,
-        );
-        return logs;
-    }
-    /**
-     * Retrieves the Ethereum address of the Exchange contract deployed on the network
-     * that the user-passed web3 provider is connected to.
-     * @returns The Ethereum address of the Exchange contract being used.
-     */
-    public getContractAddress(): string {
-        const contractAddress = this._getContractAddress(artifacts.ExchangeArtifact, this._contractAddressIfExists);
-        return contractAddress;
-    }
-    /**
-     * Checks if order is still fillable and throws an error otherwise. Useful for orderbook
-     * pruning where you want to remove stale orders without knowing who the taker will be.
-     * @param   signedOrder     An object that conforms to the SignedOrder interface. The
-     *                          signedOrder you wish to validate.
-     * @param   opts            An object that conforms to the ValidateOrderFillableOpts
-     *                          interface. Allows specifying a specific fillTakerTokenAmount
-     *                          to validate for.
-     */
-    public async validateOrderFillableOrThrowAsync(
-        signedOrder: SignedOrder,
-        opts?: ValidateOrderFillableOpts,
-    ): Promise<void> {
-        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
-        const zrxTokenAddress = this.getZRXTokenAddress();
-        const expectedFillTakerTokenAmount = !_.isUndefined(opts) ? opts.expectedFillTakerTokenAmount : undefined;
-        const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
-        await this._orderValidationUtils.validateOrderFillableOrThrowAsync(
-            exchangeTradeEmulator,
-            signedOrder,
-            zrxTokenAddress,
-            expectedFillTakerTokenAmount,
-        );
-    }
-    /**
-     * Checks if order fill will succeed and throws an error otherwise.
-     * @param   signedOrder             An object that conforms to the SignedOrder interface. The
-     *                                  signedOrder you wish to fill.
-     * @param   fillTakerTokenAmount    The total amount of the takerTokens you would like to fill.
-     * @param   takerAddress            The user Ethereum address who would like to fill this order.
-     *                                  Must be available via the supplied Provider passed to 0x.js.
-     */
-    public async validateFillOrderThrowIfInvalidAsync(
-        signedOrder: SignedOrder,
-        fillTakerTokenAmount: BigNumber,
-        takerAddress: string,
-    ): Promise<void> {
-        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
-        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
-        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
-        const normalizedTakerAddress = takerAddress.toLowerCase();
-        const zrxTokenAddress = this.getZRXTokenAddress();
-        const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
-        await this._orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
-            exchangeTradeEmulator,
-            signedOrder,
-            fillTakerTokenAmount,
-            normalizedTakerAddress,
-            zrxTokenAddress,
-        );
-    }
-    /**
-     * Checks if cancelling a given order will succeed and throws an informative error if it won't.
-     * @param   order                   An object that conforms to the Order or SignedOrder interface.
-     *                                  The order you would like to cancel.
-     * @param   cancelTakerTokenAmount  The amount (specified in taker tokens) that you would like to cancel.
-     */
-    public async validateCancelOrderThrowIfInvalidAsync(
-        order: Order,
-        cancelTakerTokenAmount: BigNumber,
-    ): Promise<void> {
-        assert.doesConformToSchema('order', order, schemas.orderSchema);
-        assert.isValidBaseUnitAmount('cancelTakerTokenAmount', cancelTakerTokenAmount);
-        const orderHash = getOrderHashHex(order);
-        const unavailableTakerTokenAmount = await this.getUnavailableTakerAmountAsync(orderHash);
-        OrderValidationUtils.validateCancelOrderThrowIfInvalid(
-            order,
-            cancelTakerTokenAmount,
-            unavailableTakerTokenAmount,
-        );
-    }
-    /**
-     * Checks if calling fillOrKill on a given order will succeed and throws an informative error if it won't.
-     * @param   signedOrder             An object that conforms to the SignedOrder interface. The
-     *                                  signedOrder you wish to fill.
-     * @param   fillTakerTokenAmount    The total amount of the takerTokens you would like to fill.
-     * @param   takerAddress            The user Ethereum address who would like to fill this order.
-     *                                  Must be available via the supplied Provider passed to 0x.js.
-     */
-    public async validateFillOrKillOrderThrowIfInvalidAsync(
-        signedOrder: SignedOrder,
-        fillTakerTokenAmount: BigNumber,
-        takerAddress: string,
-    ): Promise<void> {
-        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
-        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
-        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
-        const normalizedTakerAddress = takerAddress.toLowerCase();
-        const zrxTokenAddress = this.getZRXTokenAddress();
-        const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
-        await this._orderValidationUtils.validateFillOrKillOrderThrowIfInvalidAsync(
-            exchangeTradeEmulator,
-            signedOrder,
-            fillTakerTokenAmount,
-            normalizedTakerAddress,
-            zrxTokenAddress,
-        );
-    }
-    /**
-     * Checks if rounding error will be > 0.1% when computing makerTokenAmount by doing:
-     * `(fillTakerTokenAmount * makerTokenAmount) / takerTokenAmount`.
-     * 0x Protocol does not accept any trades that result in large rounding errors. This means that tokens with few or
-     * no decimals can only be filled in quantities and ratios that avoid large rounding errors.
-     * @param   fillTakerTokenAmount   The amount of the order (in taker tokens baseUnits) that you wish to fill.
-     * @param   takerTokenAmount       The order size on the taker side
-     * @param   makerTokenAmount       The order size on the maker side
-     */
-    public async isRoundingErrorAsync(
-        fillTakerTokenAmount: BigNumber,
-        takerTokenAmount: BigNumber,
-        makerTokenAmount: BigNumber,
-    ): Promise<boolean> {
-        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
-        assert.isValidBaseUnitAmount('takerTokenAmount', takerTokenAmount);
-        assert.isValidBaseUnitAmount('makerTokenAmount', makerTokenAmount);
-        const exchangeInstance = await this._getExchangeContractAsync();
-        const isRoundingError = await exchangeInstance.isRoundingError.callAsync(
-            fillTakerTokenAmount,
-            takerTokenAmount,
-            makerTokenAmount,
-        );
-        return isRoundingError;
-    }
-    /**
-     * Checks if logs contain LogError, which is emitted by Exchange contract on transaction failure.
-     * @param   logs   Transaction logs as returned by `zeroEx.awaitTransactionMinedAsync`
-     */
-    public throwLogErrorsAsErrors(logs: Array<LogWithDecodedArgs<DecodedLogArgs> | LogEntry>): void {
-        const errLog = _.find(logs, {
-            event: ExchangeEvents.LogError,
-        });
-        if (!_.isUndefined(errLog)) {
-            const logArgs = (errLog as LogWithDecodedArgs<LogErrorContractEventArgs>).args;
-            const errCode = logArgs.errorId;
-            const errMessage = this._exchangeContractErrCodesToMsg[errCode];
-            throw new Error(errMessage);
-        }
-    }
-    /**
-     * Gets the latest OrderState of a signedOrder
-     * @param   signedOrder   The signedOrder
-     * @param   stateLayer    Optional, desired blockchain state layer (defaults to latest).
-     * @return  OrderState of the signedOrder
-     */
-    public async getOrderStateAsync(
-        signedOrder: SignedOrder,
-        stateLayer: BlockParamLiteral = BlockParamLiteral.Latest,
-    ): Promise<OrderState> {
-        const simpleBalanceAndProxyAllowanceFetcher = new SimpleBalanceAndProxyAllowanceFetcher(
-            this._tokenWrapper,
-            stateLayer,
-        );
-        const simpleOrderFilledCancelledFetcher = new SimpleOrderFilledCancelledFetcher(this, stateLayer);
-        const orderStateUtils = new OrderStateUtils(
-            simpleBalanceAndProxyAllowanceFetcher,
-            simpleOrderFilledCancelledFetcher,
-        );
-        const orderState = orderStateUtils.getOrderStateAsync(signedOrder);
-        return orderState;
-    }
-    /**
-     * Returns the ZRX token address used by the exchange contract.
-     * @return Address of ZRX token
-     */
-    public getZRXTokenAddress(): string {
-        const contractAddress = this._getContractAddress(artifacts.ZRXArtifact, this._zrxContractAddressIfExists);
-        return contractAddress;
-    }
-    private _invalidateContractInstances(): void {
-        this.unsubscribeAll();
-        delete this._exchangeContractIfExists;
-    }
-    private async _isValidSignatureUsingContractCallAsync(
-        dataHex: string,
-        ecSignature: ECSignature,
-        signerAddressHex: string,
-    ): Promise<boolean> {
-        assert.isHexString('dataHex', dataHex);
-        assert.doesConformToSchema('ecSignature', ecSignature, schemas.ecSignatureSchema);
-        assert.isETHAddressHex('signerAddressHex', signerAddressHex);
-        const normalizedSignerAddress = signerAddressHex.toLowerCase();
-
-        const exchangeInstance = await this._getExchangeContractAsync();
-
-        const isValidSignature = await exchangeInstance.isValidSignature.callAsync(
-            normalizedSignerAddress,
-            dataHex,
-            ecSignature.v,
-            ecSignature.r,
-            ecSignature.s,
-        );
-        return isValidSignature;
-    }
-    private async _getOrderHashHexUsingContractCallAsync(order: Order | SignedOrder): Promise<string> {
-        const exchangeInstance = await this._getExchangeContractAsync();
-        const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(order);
-        const orderHashHex = await exchangeInstance.getOrderHash.callAsync(orderAddresses, orderValues);
-        return orderHashHex;
-    }
-    private async _getExchangeContractAsync(): Promise<ExchangeContract> {
-        if (!_.isUndefined(this._exchangeContractIfExists)) {
-            return this._exchangeContractIfExists;
-        }
-        const [abi, address] = await this._getContractAbiAndAddressFromArtifactsAsync(
-            artifacts.ExchangeArtifact,
-            this._contractAddressIfExists,
-        );
-        const contractInstance = new ExchangeContract(
-            abi,
-            address,
-            this._web3Wrapper.getProvider(),
-            this._web3Wrapper.getContractDefaults(),
-        );
-        this._exchangeContractIfExists = contractInstance;
-        return this._exchangeContractIfExists;
-    }
-    private async _getTokenTransferProxyAddressAsync(): Promise<string> {
-        const exchangeInstance = await this._getExchangeContractAsync();
-        const tokenTransferProxyAddress = await exchangeInstance.TOKEN_TRANSFER_PROXY_CONTRACT.callAsync();
-        const tokenTransferProxyAddressLowerCase = tokenTransferProxyAddress.toLowerCase();
-        return tokenTransferProxyAddressLowerCase;
-    }
-} // tslint:disable:max-file-line-count
diff --git a/packages/0x.js/src/contract_wrappers/token_registry_wrapper.ts b/packages/0x.js/src/contract_wrappers/token_registry_wrapper.ts
deleted file mode 100644
index c4a193264..000000000
--- a/packages/0x.js/src/contract_wrappers/token_registry_wrapper.ts
+++ /dev/null
@@ -1,133 +0,0 @@
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
-import * as _ from 'lodash';
-
-import { artifacts } from '../artifacts';
-import { Token, TokenMetadata } from '../types';
-import { assert } from '../utils/assert';
-import { constants } from '../utils/constants';
-
-import { ContractWrapper } from './contract_wrapper';
-import { TokenRegistryContract } from './generated/token_registry';
-
-/**
- * This class includes all the functionality related to interacting with the 0x Token Registry smart contract.
- */
-export class TokenRegistryWrapper extends ContractWrapper {
-    private _tokenRegistryContractIfExists?: TokenRegistryContract;
-    private _contractAddressIfExists?: string;
-    private static _createTokenFromMetadata(metadata: TokenMetadata): Token | undefined {
-        if (metadata[0] === constants.NULL_ADDRESS) {
-            return undefined;
-        }
-        const token = {
-            address: metadata[0],
-            name: metadata[1],
-            symbol: metadata[2],
-            decimals: metadata[3],
-        };
-        return token;
-    }
-    constructor(web3Wrapper: Web3Wrapper, networkId: number, contractAddressIfExists?: string) {
-        super(web3Wrapper, networkId);
-        this._contractAddressIfExists = contractAddressIfExists;
-    }
-    /**
-     * Retrieves all the tokens currently listed in the Token Registry smart contract
-     * @return  An array of objects that conform to the Token interface.
-     */
-    public async getTokensAsync(): Promise<Token[]> {
-        const addresses = await this.getTokenAddressesAsync();
-        const tokenPromises: Array<Promise<Token | undefined>> = _.map(addresses, async (address: string) =>
-            this.getTokenIfExistsAsync(address),
-        );
-        const tokens = await Promise.all(tokenPromises);
-        return tokens as Token[];
-    }
-    /**
-     * Retrieves all the addresses of the tokens currently listed in the Token Registry smart contract
-     * @return  An array of token addresses.
-     */
-    public async getTokenAddressesAsync(): Promise<string[]> {
-        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
-        const addresses = await tokenRegistryContract.getTokenAddresses.callAsync();
-        const lowerCaseAddresses = _.map(addresses, address => address.toLowerCase());
-        return lowerCaseAddresses;
-    }
-    /**
-     * Retrieves a token by address currently listed in the Token Registry smart contract
-     * @return  An object that conforms to the Token interface or undefined if token not found.
-     */
-    public async getTokenIfExistsAsync(address: string): Promise<Token | undefined> {
-        assert.isETHAddressHex('address', address);
-        const normalizedAddress = address.toLowerCase();
-
-        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
-        const metadata = await tokenRegistryContract.getTokenMetaData.callAsync(normalizedAddress);
-        const token = TokenRegistryWrapper._createTokenFromMetadata(metadata);
-        return token;
-    }
-    public async getTokenAddressBySymbolIfExistsAsync(symbol: string): Promise<string | undefined> {
-        assert.isString('symbol', symbol);
-        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
-        const addressIfExists = await tokenRegistryContract.getTokenAddressBySymbol.callAsync(symbol);
-        if (addressIfExists === constants.NULL_ADDRESS) {
-            return undefined;
-        }
-        return addressIfExists;
-    }
-    public async getTokenAddressByNameIfExistsAsync(name: string): Promise<string | undefined> {
-        assert.isString('name', name);
-        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
-        const addressIfExists = await tokenRegistryContract.getTokenAddressByName.callAsync(name);
-        if (addressIfExists === constants.NULL_ADDRESS) {
-            return undefined;
-        }
-        return addressIfExists;
-    }
-    public async getTokenBySymbolIfExistsAsync(symbol: string): Promise<Token | undefined> {
-        assert.isString('symbol', symbol);
-        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
-        const metadata = await tokenRegistryContract.getTokenBySymbol.callAsync(symbol);
-        const token = TokenRegistryWrapper._createTokenFromMetadata(metadata);
-        return token;
-    }
-    public async getTokenByNameIfExistsAsync(name: string): Promise<Token | undefined> {
-        assert.isString('name', name);
-        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
-        const metadata = await tokenRegistryContract.getTokenByName.callAsync(name);
-        const token = TokenRegistryWrapper._createTokenFromMetadata(metadata);
-        return token;
-    }
-    /**
-     * Retrieves the Ethereum address of the TokenRegistry contract deployed on the network
-     * that the user-passed web3 provider is connected to.
-     * @returns The Ethereum address of the TokenRegistry contract being used.
-     */
-    public getContractAddress(): string {
-        const contractAddress = this._getContractAddress(
-            artifacts.TokenRegistryArtifact,
-            this._contractAddressIfExists,
-        );
-        return contractAddress;
-    }
-    private _invalidateContractInstance(): void {
-        delete this._tokenRegistryContractIfExists;
-    }
-    private async _getTokenRegistryContractAsync(): Promise<TokenRegistryContract> {
-        if (!_.isUndefined(this._tokenRegistryContractIfExists)) {
-            return this._tokenRegistryContractIfExists;
-        }
-        const [abi, address] = await this._getContractAbiAndAddressFromArtifactsAsync(
-            artifacts.TokenRegistryArtifact,
-            this._contractAddressIfExists,
-        );
-        const contractInstance = new TokenRegistryContract(
-            abi,
-            address,
-            this._web3Wrapper.getProvider(),
-            this._web3Wrapper.getContractDefaults(),
-        );
-        this._tokenRegistryContractIfExists = contractInstance;
-        return this._tokenRegistryContractIfExists;
-    }
-}
diff --git a/packages/0x.js/src/contract_wrappers/token_transfer_proxy_wrapper.ts b/packages/0x.js/src/contract_wrappers/token_transfer_proxy_wrapper.ts
deleted file mode 100644
index be558b5be..000000000
--- a/packages/0x.js/src/contract_wrappers/token_transfer_proxy_wrapper.ts
+++ /dev/null
@@ -1,75 +0,0 @@
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
-import * as _ from 'lodash';
-
-import { artifacts } from '../artifacts';
-import { assert } from '../utils/assert';
-
-import { ContractWrapper } from './contract_wrapper';
-import { TokenTransferProxyContract } from './generated/token_transfer_proxy';
-
-/**
- * This class includes the functionality related to interacting with the TokenTransferProxy contract.
- */
-export class TokenTransferProxyWrapper extends ContractWrapper {
-    private _tokenTransferProxyContractIfExists?: TokenTransferProxyContract;
-    private _contractAddressIfExists?: string;
-    constructor(web3Wrapper: Web3Wrapper, networkId: number, contractAddressIfExists?: string) {
-        super(web3Wrapper, networkId);
-        this._contractAddressIfExists = contractAddressIfExists;
-    }
-    /**
-     * Check if the Exchange contract address is authorized by the TokenTransferProxy contract.
-     * @param   exchangeContractAddress     The hex encoded address of the Exchange contract to call.
-     * @return  Whether the exchangeContractAddress is authorized.
-     */
-    public async isAuthorizedAsync(exchangeContractAddress: string): Promise<boolean> {
-        assert.isETHAddressHex('exchangeContractAddress', exchangeContractAddress);
-        const normalizedExchangeContractAddress = exchangeContractAddress.toLowerCase();
-        const tokenTransferProxyContractInstance = await this._getTokenTransferProxyContractAsync();
-        const isAuthorized = await tokenTransferProxyContractInstance.authorized.callAsync(
-            normalizedExchangeContractAddress,
-        );
-        return isAuthorized;
-    }
-    /**
-     * Get the list of all Exchange contract addresses authorized by the TokenTransferProxy contract.
-     * @return  The list of authorized addresses.
-     */
-    public async getAuthorizedAddressesAsync(): Promise<string[]> {
-        const tokenTransferProxyContractInstance = await this._getTokenTransferProxyContractAsync();
-        const authorizedAddresses = await tokenTransferProxyContractInstance.getAuthorizedAddresses.callAsync();
-        return authorizedAddresses;
-    }
-    /**
-     * Retrieves the Ethereum address of the TokenTransferProxy contract deployed on the network
-     * that the user-passed web3 provider is connected to.
-     * @returns The Ethereum address of the TokenTransferProxy contract being used.
-     */
-    public getContractAddress(): string {
-        const contractAddress = this._getContractAddress(
-            artifacts.TokenTransferProxyArtifact,
-            this._contractAddressIfExists,
-        );
-        return contractAddress;
-    }
-    private _invalidateContractInstance(): void {
-        delete this._tokenTransferProxyContractIfExists;
-    }
-    private async _getTokenTransferProxyContractAsync(): Promise<TokenTransferProxyContract> {
-        if (!_.isUndefined(this._tokenTransferProxyContractIfExists)) {
-            return this._tokenTransferProxyContractIfExists;
-        }
-        const [abi, address] = await this._getContractAbiAndAddressFromArtifactsAsync(
-            artifacts.TokenTransferProxyArtifact,
-            this._contractAddressIfExists,
-        );
-        const contractInstance = new TokenTransferProxyContract(
-            abi,
-            address,
-            this._web3Wrapper.getProvider(),
-            this._web3Wrapper.getContractDefaults(),
-        );
-        this._tokenTransferProxyContractIfExists = contractInstance;
-        return this._tokenTransferProxyContractIfExists;
-    }
-}
diff --git a/packages/0x.js/src/contract_wrappers/token_wrapper.ts b/packages/0x.js/src/contract_wrappers/token_wrapper.ts
deleted file mode 100644
index 194cfb5aa..000000000
--- a/packages/0x.js/src/contract_wrappers/token_wrapper.ts
+++ /dev/null
@@ -1,434 +0,0 @@
-import { schemas } from '@0xproject/json-schemas';
-import { LogWithDecodedArgs } from '@0xproject/types';
-import { AbiDecoder, BigNumber } from '@0xproject/utils';
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
-import * as _ from 'lodash';
-
-import { artifacts } from '../artifacts';
-import { BlockRange, EventCallback, IndexedFilterValues, MethodOpts, TransactionOpts, ZeroExError } from '../types';
-import { assert } from '../utils/assert';
-import { constants } from '../utils/constants';
-
-import { ContractWrapper } from './contract_wrapper';
-import { TokenContract, TokenContractEventArgs, TokenEvents } from './generated/token';
-import { TokenTransferProxyWrapper } from './token_transfer_proxy_wrapper';
-
-/**
- * This class includes all the functionality related to interacting with ERC20 token contracts.
- * All ERC20 method calls are supported, along with some convenience methods for getting/setting allowances
- * to the 0x Proxy smart contract.
- */
-export class TokenWrapper extends ContractWrapper {
-    public UNLIMITED_ALLOWANCE_IN_BASE_UNITS = constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
-    private _tokenContractsByAddress: { [address: string]: TokenContract };
-    private _tokenTransferProxyWrapper: TokenTransferProxyWrapper;
-    constructor(web3Wrapper: Web3Wrapper, networkId: number, tokenTransferProxyWrapper: TokenTransferProxyWrapper) {
-        super(web3Wrapper, networkId);
-        this._tokenContractsByAddress = {};
-        this._tokenTransferProxyWrapper = tokenTransferProxyWrapper;
-    }
-    /**
-     * Retrieves an owner's ERC20 token balance.
-     * @param   tokenAddress    The hex encoded contract Ethereum address where the ERC20 token is deployed.
-     * @param   ownerAddress    The hex encoded user Ethereum address whose balance you would like to check.
-     * @param   methodOpts      Optional arguments this method accepts.
-     * @return  The owner's ERC20 token balance in base units.
-     */
-    public async getBalanceAsync(
-        tokenAddress: string,
-        ownerAddress: string,
-        methodOpts?: MethodOpts,
-    ): Promise<BigNumber> {
-        assert.isETHAddressHex('ownerAddress', ownerAddress);
-        assert.isETHAddressHex('tokenAddress', tokenAddress);
-        const normalizedTokenAddress = tokenAddress.toLowerCase();
-        const normalizedOwnerAddress = ownerAddress.toLowerCase();
-
-        const tokenContract = await this._getTokenContractAsync(normalizedTokenAddress);
-        const defaultBlock = _.isUndefined(methodOpts) ? undefined : methodOpts.defaultBlock;
-        const txData = {};
-        let balance = await tokenContract.balanceOf.callAsync(normalizedOwnerAddress, txData, defaultBlock);
-        // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
-        balance = new BigNumber(balance);
-        return balance;
-    }
-    /**
-     * Sets the spender's allowance to a specified number of baseUnits on behalf of the owner address.
-     * Equivalent to the ERC20 spec method `approve`.
-     * @param   tokenAddress        The hex encoded contract Ethereum address where the ERC20 token is deployed.
-     * @param   ownerAddress        The hex encoded user Ethereum address who would like to set an allowance
-     *                              for spenderAddress.
-     * @param   spenderAddress      The hex encoded user Ethereum address who will be able to spend the set allowance.
-     * @param   amountInBaseUnits   The allowance amount you would like to set.
-     * @param   txOpts              Transaction parameters.
-     * @return Transaction hash.
-     */
-    public async setAllowanceAsync(
-        tokenAddress: string,
-        ownerAddress: string,
-        spenderAddress: string,
-        amountInBaseUnits: BigNumber,
-        txOpts: TransactionOpts = {},
-    ): Promise<string> {
-        assert.isETHAddressHex('spenderAddress', spenderAddress);
-        assert.isETHAddressHex('tokenAddress', tokenAddress);
-        await assert.isSenderAddressAsync('ownerAddress', ownerAddress, this._web3Wrapper);
-        const normalizedTokenAddress = tokenAddress.toLowerCase();
-        const normalizedSpenderAddress = spenderAddress.toLowerCase();
-        const normalizedOwnerAddress = ownerAddress.toLowerCase();
-        assert.isValidBaseUnitAmount('amountInBaseUnits', amountInBaseUnits);
-
-        const tokenContract = await this._getTokenContractAsync(normalizedTokenAddress);
-        const txHash = await tokenContract.approve.sendTransactionAsync(normalizedSpenderAddress, amountInBaseUnits, {
-            from: normalizedOwnerAddress,
-            gas: txOpts.gasLimit,
-            gasPrice: txOpts.gasPrice,
-        });
-        return txHash;
-    }
-    /**
-     * Sets the spender's allowance to an unlimited number of baseUnits on behalf of the owner address.
-     * Equivalent to the ERC20 spec method `approve`.
-     * Setting an unlimited allowance will lower the gas cost for filling orders involving tokens that forego updating
-     * allowances set to the max amount (e.g ZRX, WETH)
-     * @param   tokenAddress        The hex encoded contract Ethereum address where the ERC20 token is deployed.
-     * @param   ownerAddress        The hex encoded user Ethereum address who would like to set an allowance
-     *                              for spenderAddress.
-     * @param   spenderAddress      The hex encoded user Ethereum address who will be able to spend the set allowance.
-     * @param   txOpts              Transaction parameters.
-     * @return Transaction hash.
-     */
-    public async setUnlimitedAllowanceAsync(
-        tokenAddress: string,
-        ownerAddress: string,
-        spenderAddress: string,
-        txOpts: TransactionOpts = {},
-    ): Promise<string> {
-        assert.isETHAddressHex('ownerAddress', ownerAddress);
-        assert.isETHAddressHex('tokenAddress', tokenAddress);
-        assert.isETHAddressHex('spenderAddress', spenderAddress);
-        const normalizedTokenAddress = tokenAddress.toLowerCase();
-        const normalizedOwnerAddress = ownerAddress.toLowerCase();
-        const normalizedSpenderAddress = spenderAddress.toLowerCase();
-        const txHash = await this.setAllowanceAsync(
-            normalizedTokenAddress,
-            normalizedOwnerAddress,
-            normalizedSpenderAddress,
-            this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
-            txOpts,
-        );
-        return txHash;
-    }
-    /**
-     * Retrieves the owners allowance in baseUnits set to the spender's address.
-     * @param   tokenAddress    The hex encoded contract Ethereum address where the ERC20 token is deployed.
-     * @param   ownerAddress    The hex encoded user Ethereum address whose allowance to spenderAddress
-     *                          you would like to retrieve.
-     * @param   spenderAddress  The hex encoded user Ethereum address who can spend the allowance you are fetching.
-     * @param   methodOpts      Optional arguments this method accepts.
-     */
-    public async getAllowanceAsync(
-        tokenAddress: string,
-        ownerAddress: string,
-        spenderAddress: string,
-        methodOpts?: MethodOpts,
-    ): Promise<BigNumber> {
-        assert.isETHAddressHex('ownerAddress', ownerAddress);
-        assert.isETHAddressHex('tokenAddress', tokenAddress);
-        assert.isETHAddressHex('spenderAddress', spenderAddress);
-        const normalizedTokenAddress = tokenAddress.toLowerCase();
-        const normalizedOwnerAddress = ownerAddress.toLowerCase();
-        const normalizedSpenderAddress = spenderAddress.toLowerCase();
-
-        const tokenContract = await this._getTokenContractAsync(normalizedTokenAddress);
-        const defaultBlock = _.isUndefined(methodOpts) ? undefined : methodOpts.defaultBlock;
-        const txData = {};
-        let allowanceInBaseUnits = await tokenContract.allowance.callAsync(
-            normalizedOwnerAddress,
-            normalizedSpenderAddress,
-            txData,
-            defaultBlock,
-        );
-        // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
-        allowanceInBaseUnits = new BigNumber(allowanceInBaseUnits);
-        return allowanceInBaseUnits;
-    }
-    /**
-     * Retrieves the owner's allowance in baseUnits set to the 0x proxy contract.
-     * @param   tokenAddress    The hex encoded contract Ethereum address where the ERC20 token is deployed.
-     * @param   ownerAddress    The hex encoded user Ethereum address whose proxy contract allowance we are retrieving.
-     * @param   methodOpts      Optional arguments this method accepts.
-     */
-    public async getProxyAllowanceAsync(
-        tokenAddress: string,
-        ownerAddress: string,
-        methodOpts?: MethodOpts,
-    ): Promise<BigNumber> {
-        assert.isETHAddressHex('ownerAddress', ownerAddress);
-        assert.isETHAddressHex('tokenAddress', tokenAddress);
-        const normalizedTokenAddress = tokenAddress.toLowerCase();
-        const normalizedOwnerAddress = ownerAddress.toLowerCase();
-
-        const proxyAddress = this._tokenTransferProxyWrapper.getContractAddress();
-        const allowanceInBaseUnits = await this.getAllowanceAsync(
-            normalizedTokenAddress,
-            normalizedOwnerAddress,
-            proxyAddress,
-            methodOpts,
-        );
-        return allowanceInBaseUnits;
-    }
-    /**
-     * Sets the 0x proxy contract's allowance to a specified number of a tokens' baseUnits on behalf
-     * of an owner address.
-     * @param   tokenAddress        The hex encoded contract Ethereum address where the ERC20 token is deployed.
-     * @param   ownerAddress        The hex encoded user Ethereum address who is setting an allowance
-     *                              for the Proxy contract.
-     * @param   amountInBaseUnits   The allowance amount specified in baseUnits.
-     * @param   txOpts              Transaction parameters.
-     * @return Transaction hash.
-     */
-    public async setProxyAllowanceAsync(
-        tokenAddress: string,
-        ownerAddress: string,
-        amountInBaseUnits: BigNumber,
-        txOpts: TransactionOpts = {},
-    ): Promise<string> {
-        assert.isETHAddressHex('ownerAddress', ownerAddress);
-        assert.isETHAddressHex('tokenAddress', tokenAddress);
-        const normalizedTokenAddress = tokenAddress.toLowerCase();
-        const normalizedOwnerAddress = ownerAddress.toLowerCase();
-        assert.isValidBaseUnitAmount('amountInBaseUnits', amountInBaseUnits);
-
-        const proxyAddress = this._tokenTransferProxyWrapper.getContractAddress();
-        const txHash = await this.setAllowanceAsync(
-            normalizedTokenAddress,
-            normalizedOwnerAddress,
-            proxyAddress,
-            amountInBaseUnits,
-            txOpts,
-        );
-        return txHash;
-    }
-    /**
-     * Sets the 0x proxy contract's allowance to a unlimited number of a tokens' baseUnits on behalf
-     * of an owner address.
-     * Setting an unlimited allowance will lower the gas cost for filling orders involving tokens that forego updating
-     * allowances set to the max amount (e.g ZRX, WETH)
-     * @param   tokenAddress        The hex encoded contract Ethereum address where the ERC20 token is deployed.
-     * @param   ownerAddress        The hex encoded user Ethereum address who is setting an allowance
-     *                              for the Proxy contract.
-     * @param   txOpts              Transaction parameters.
-     * @return Transaction hash.
-     */
-    public async setUnlimitedProxyAllowanceAsync(
-        tokenAddress: string,
-        ownerAddress: string,
-        txOpts: TransactionOpts = {},
-    ): Promise<string> {
-        assert.isETHAddressHex('ownerAddress', ownerAddress);
-        assert.isETHAddressHex('tokenAddress', tokenAddress);
-        const normalizedTokenAddress = tokenAddress.toLowerCase();
-        const normalizedOwnerAddress = ownerAddress.toLowerCase();
-        const txHash = await this.setProxyAllowanceAsync(
-            normalizedTokenAddress,
-            normalizedOwnerAddress,
-            this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
-            txOpts,
-        );
-        return txHash;
-    }
-    /**
-     * Transfers `amountInBaseUnits` ERC20 tokens from `fromAddress` to `toAddress`.
-     * @param   tokenAddress        The hex encoded contract Ethereum address where the ERC20 token is deployed.
-     * @param   fromAddress         The hex encoded user Ethereum address that will send the funds.
-     * @param   toAddress           The hex encoded user Ethereum address that will receive the funds.
-     * @param   amountInBaseUnits   The amount (specified in baseUnits) of the token to transfer.
-     * @param   txOpts              Transaction parameters.
-     * @return Transaction hash.
-     */
-    public async transferAsync(
-        tokenAddress: string,
-        fromAddress: string,
-        toAddress: string,
-        amountInBaseUnits: BigNumber,
-        txOpts: TransactionOpts = {},
-    ): Promise<string> {
-        assert.isETHAddressHex('tokenAddress', tokenAddress);
-        assert.isETHAddressHex('toAddress', toAddress);
-        await assert.isSenderAddressAsync('fromAddress', fromAddress, this._web3Wrapper);
-        const normalizedTokenAddress = tokenAddress.toLowerCase();
-        const normalizedFromAddress = fromAddress.toLowerCase();
-        const normalizedToAddress = toAddress.toLowerCase();
-        assert.isValidBaseUnitAmount('amountInBaseUnits', amountInBaseUnits);
-
-        const tokenContract = await this._getTokenContractAsync(normalizedTokenAddress);
-
-        const fromAddressBalance = await this.getBalanceAsync(normalizedTokenAddress, normalizedFromAddress);
-        if (fromAddressBalance.lessThan(amountInBaseUnits)) {
-            throw new Error(ZeroExError.InsufficientBalanceForTransfer);
-        }
-
-        const txHash = await tokenContract.transfer.sendTransactionAsync(normalizedToAddress, amountInBaseUnits, {
-            from: normalizedFromAddress,
-            gas: txOpts.gasLimit,
-            gasPrice: txOpts.gasPrice,
-        });
-        return txHash;
-    }
-    /**
-     * Transfers `amountInBaseUnits` ERC20 tokens from `fromAddress` to `toAddress`.
-     * Requires the fromAddress to have sufficient funds and to have approved an allowance of
-     * `amountInBaseUnits` to `senderAddress`.
-     * @param   tokenAddress        The hex encoded contract Ethereum address where the ERC20 token is deployed.
-     * @param   fromAddress         The hex encoded user Ethereum address whose funds are being sent.
-     * @param   toAddress           The hex encoded user Ethereum address that will receive the funds.
-     * @param   senderAddress       The hex encoded user Ethereum address whose initiates the fund transfer. The
-     *                              `fromAddress` must have set an allowance to the `senderAddress`
-     *                              before this call.
-     * @param   amountInBaseUnits   The amount (specified in baseUnits) of the token to transfer.
-     * @param   txOpts              Transaction parameters.
-     * @return Transaction hash.
-     */
-    public async transferFromAsync(
-        tokenAddress: string,
-        fromAddress: string,
-        toAddress: string,
-        senderAddress: string,
-        amountInBaseUnits: BigNumber,
-        txOpts: TransactionOpts = {},
-    ): Promise<string> {
-        assert.isETHAddressHex('toAddress', toAddress);
-        assert.isETHAddressHex('fromAddress', fromAddress);
-        assert.isETHAddressHex('tokenAddress', tokenAddress);
-        await assert.isSenderAddressAsync('senderAddress', senderAddress, this._web3Wrapper);
-        const normalizedToAddress = toAddress.toLowerCase();
-        const normalizedFromAddress = fromAddress.toLowerCase();
-        const normalizedTokenAddress = tokenAddress.toLowerCase();
-        const normalizedSenderAddress = senderAddress.toLowerCase();
-        assert.isValidBaseUnitAmount('amountInBaseUnits', amountInBaseUnits);
-
-        const tokenContract = await this._getTokenContractAsync(normalizedTokenAddress);
-
-        const fromAddressAllowance = await this.getAllowanceAsync(
-            normalizedTokenAddress,
-            normalizedFromAddress,
-            normalizedSenderAddress,
-        );
-        if (fromAddressAllowance.lessThan(amountInBaseUnits)) {
-            throw new Error(ZeroExError.InsufficientAllowanceForTransfer);
-        }
-
-        const fromAddressBalance = await this.getBalanceAsync(normalizedTokenAddress, normalizedFromAddress);
-        if (fromAddressBalance.lessThan(amountInBaseUnits)) {
-            throw new Error(ZeroExError.InsufficientBalanceForTransfer);
-        }
-
-        const txHash = await tokenContract.transferFrom.sendTransactionAsync(
-            normalizedFromAddress,
-            normalizedToAddress,
-            amountInBaseUnits,
-            {
-                from: normalizedSenderAddress,
-                gas: txOpts.gasLimit,
-                gasPrice: txOpts.gasPrice,
-            },
-        );
-        return txHash;
-    }
-    /**
-     * Subscribe to an event type emitted by the Token contract.
-     * @param   tokenAddress        The hex encoded address where the ERC20 token is deployed.
-     * @param   eventName           The token contract event you would like to subscribe to.
-     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
-     *                              the value is the value you are interested in. E.g `{maker: aUserAddressHex}`
-     * @param   callback            Callback that gets called when a log is added/removed
-     * @return Subscription token used later to unsubscribe
-     */
-    public subscribe<ArgsType extends TokenContractEventArgs>(
-        tokenAddress: string,
-        eventName: TokenEvents,
-        indexFilterValues: IndexedFilterValues,
-        callback: EventCallback<ArgsType>,
-    ): string {
-        assert.isETHAddressHex('tokenAddress', tokenAddress);
-        const normalizedTokenAddress = tokenAddress.toLowerCase();
-        assert.doesBelongToStringEnum('eventName', eventName, TokenEvents);
-        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
-        assert.isFunction('callback', callback);
-        const subscriptionToken = this._subscribe<ArgsType>(
-            normalizedTokenAddress,
-            eventName,
-            indexFilterValues,
-            artifacts.TokenArtifact.abi,
-            callback,
-        );
-        return subscriptionToken;
-    }
-    /**
-     * Cancel a subscription
-     * @param   subscriptionToken Subscription token returned by `subscribe()`
-     */
-    public unsubscribe(subscriptionToken: string): void {
-        this._unsubscribe(subscriptionToken);
-    }
-    /**
-     * Cancels all existing subscriptions
-     */
-    public unsubscribeAll(): void {
-        super._unsubscribeAll();
-    }
-    /**
-     * Gets historical logs without creating a subscription
-     * @param   tokenAddress        An address of the token that emitted the logs.
-     * @param   eventName           The token contract event you would like to subscribe to.
-     * @param   blockRange          Block range to get logs from.
-     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
-     *                              the value is the value you are interested in. E.g `{_from: aUserAddressHex}`
-     * @return  Array of logs that match the parameters
-     */
-    public async getLogsAsync<ArgsType extends TokenContractEventArgs>(
-        tokenAddress: string,
-        eventName: TokenEvents,
-        blockRange: BlockRange,
-        indexFilterValues: IndexedFilterValues,
-    ): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
-        assert.isETHAddressHex('tokenAddress', tokenAddress);
-        const normalizedTokenAddress = tokenAddress.toLowerCase();
-        assert.doesBelongToStringEnum('eventName', eventName, TokenEvents);
-        assert.doesConformToSchema('blockRange', blockRange, schemas.blockRangeSchema);
-        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
-        const logs = await this._getLogsAsync<ArgsType>(
-            normalizedTokenAddress,
-            eventName,
-            blockRange,
-            indexFilterValues,
-            artifacts.TokenArtifact.abi,
-        );
-        return logs;
-    }
-    private _invalidateContractInstances(): void {
-        this.unsubscribeAll();
-        this._tokenContractsByAddress = {};
-    }
-    private async _getTokenContractAsync(tokenAddress: string): Promise<TokenContract> {
-        const normalizedTokenAddress = tokenAddress.toLowerCase();
-        let tokenContract = this._tokenContractsByAddress[normalizedTokenAddress];
-        if (!_.isUndefined(tokenContract)) {
-            return tokenContract;
-        }
-        const [abi, address] = await this._getContractAbiAndAddressFromArtifactsAsync(
-            artifacts.TokenArtifact,
-            normalizedTokenAddress,
-        );
-        const contractInstance = new TokenContract(
-            abi,
-            address,
-            this._web3Wrapper.getProvider(),
-            this._web3Wrapper.getContractDefaults(),
-        );
-        tokenContract = contractInstance;
-        this._tokenContractsByAddress[normalizedTokenAddress] = tokenContract;
-        return tokenContract;
-    }
-}
diff --git a/packages/0x.js/src/fetchers/simple_balance_and_proxy_allowance_fetcher.ts b/packages/0x.js/src/fetchers/simple_balance_and_proxy_allowance_fetcher.ts
deleted file mode 100644
index 21774d794..000000000
--- a/packages/0x.js/src/fetchers/simple_balance_and_proxy_allowance_fetcher.ts
+++ /dev/null
@@ -1,28 +0,0 @@
-import { BlockParamLiteral } from '@0xproject/types';
-import { BigNumber } from '@0xproject/utils';
-
-import { BalanceAndProxyAllowanceFetcher } from '../abstract/balance_and_proxy_allowance_fetcher';
-import { TokenWrapper } from '../contract_wrappers/token_wrapper';
-
-export class SimpleBalanceAndProxyAllowanceFetcher implements BalanceAndProxyAllowanceFetcher {
-    private _tokenWrapper: TokenWrapper;
-    private _defaultBlock: BlockParamLiteral;
-    constructor(token: TokenWrapper, defaultBlock: BlockParamLiteral) {
-        this._tokenWrapper = token;
-        this._defaultBlock = defaultBlock;
-    }
-    public async getBalanceAsync(tokenAddress: string, userAddress: string): Promise<BigNumber> {
-        const methodOpts = {
-            defaultBlock: this._defaultBlock,
-        };
-        const balance = this._tokenWrapper.getBalanceAsync(tokenAddress, userAddress, methodOpts);
-        return balance;
-    }
-    public async getProxyAllowanceAsync(tokenAddress: string, userAddress: string): Promise<BigNumber> {
-        const methodOpts = {
-            defaultBlock: this._defaultBlock,
-        };
-        const proxyAllowance = this._tokenWrapper.getProxyAllowanceAsync(tokenAddress, userAddress, methodOpts);
-        return proxyAllowance;
-    }
-}
diff --git a/packages/0x.js/src/fetchers/simple_order_filled_cancelled_fetcher.ts b/packages/0x.js/src/fetchers/simple_order_filled_cancelled_fetcher.ts
deleted file mode 100644
index b7548d54d..000000000
--- a/packages/0x.js/src/fetchers/simple_order_filled_cancelled_fetcher.ts
+++ /dev/null
@@ -1,28 +0,0 @@
-import { BlockParamLiteral } from '@0xproject/types';
-import { BigNumber } from '@0xproject/utils';
-
-import { OrderFilledCancelledFetcher } from '../abstract/order_filled_cancelled_fetcher';
-import { ExchangeWrapper } from '../contract_wrappers/exchange_wrapper';
-
-export class SimpleOrderFilledCancelledFetcher implements OrderFilledCancelledFetcher {
-    private _exchangeWrapper: ExchangeWrapper;
-    private _defaultBlock: BlockParamLiteral;
-    constructor(exchange: ExchangeWrapper, defaultBlock: BlockParamLiteral) {
-        this._exchangeWrapper = exchange;
-        this._defaultBlock = defaultBlock;
-    }
-    public async getFilledTakerAmountAsync(orderHash: string): Promise<BigNumber> {
-        const methodOpts = {
-            defaultBlock: this._defaultBlock,
-        };
-        const filledTakerAmount = this._exchangeWrapper.getFilledTakerAmountAsync(orderHash, methodOpts);
-        return filledTakerAmount;
-    }
-    public async getCancelledTakerAmountAsync(orderHash: string): Promise<BigNumber> {
-        const methodOpts = {
-            defaultBlock: this._defaultBlock,
-        };
-        const cancelledTakerAmount = this._exchangeWrapper.getCancelledTakerAmountAsync(orderHash, methodOpts);
-        return cancelledTakerAmount;
-    }
-}
diff --git a/packages/0x.js/src/index.ts b/packages/0x.js/src/index.ts
index 3b973bd54..e9528d4d1 100644
--- a/packages/0x.js/src/index.ts
+++ b/packages/0x.js/src/index.ts
@@ -1,61 +1,51 @@
 export { ZeroEx } from './0x';
 
 export {
-    ZeroExError,
-    EventCallback,
-    ExchangeContractErrs,
-    ContractEvent,
-    Token,
-    IndexedFilterValues,
-    BlockRange,
-    OrderCancellationRequest,
-    OrderFillRequest,
-    ContractEventArgs,
-    ZeroExConfig,
-    MethodOpts,
-    OrderTransactionOpts,
-    TransactionOpts,
-    LogEvent,
-    DecodedLogEvent,
-    EventWatcherCallback,
-    OnOrderStateChangeCallback,
-    OrderStateValid,
-    OrderStateInvalid,
-    OrderState,
-} from './types';
-
-export {
     BlockParamLiteral,
     FilterObject,
     BlockParam,
     ContractEventArg,
+    ExchangeContractErrs,
     LogWithDecodedArgs,
     Order,
     Provider,
     SignedOrder,
     ECSignature,
+    OrderStateValid,
+    OrderStateInvalid,
+    OrderState,
+    Token,
     TransactionReceipt,
     TransactionReceiptWithDecodedLogs,
 } from '@0xproject/types';
 
 export {
+    EventCallback,
+    ContractEvent,
+    IndexedFilterValues,
+    BlockRange,
+    OrderCancellationRequest,
+    OrderFillRequest,
+    ContractEventArgs,
+    MethodOpts,
+    OrderTransactionOpts,
+    TransactionOpts,
+    LogEvent,
+    DecodedLogEvent,
+    OnOrderStateChangeCallback,
+    ContractWrappersError,
     EtherTokenContractEventArgs,
     WithdrawalContractEventArgs,
     DepositContractEventArgs,
     EtherTokenEvents,
-} from './contract_wrappers/generated/ether_token';
-
-export {
     TransferContractEventArgs,
     ApprovalContractEventArgs,
     TokenContractEventArgs,
     TokenEvents,
-} from './contract_wrappers/generated/token';
-
-export {
     LogErrorContractEventArgs,
     LogCancelContractEventArgs,
     LogFillContractEventArgs,
     ExchangeContractEventArgs,
     ExchangeEvents,
-} from './contract_wrappers/generated/exchange';
+    ZeroExContractConfig,
+} from '@0xproject/contract-wrappers';
diff --git a/packages/0x.js/src/order_watcher/event_watcher.ts b/packages/0x.js/src/order_watcher/event_watcher.ts
deleted file mode 100644
index de5a99a46..000000000
--- a/packages/0x.js/src/order_watcher/event_watcher.ts
+++ /dev/null
@@ -1,99 +0,0 @@
-import { BlockParamLiteral, LogEntry } from '@0xproject/types';
-import { intervalUtils } from '@0xproject/utils';
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
-import * as _ from 'lodash';
-
-import { EventWatcherCallback, ZeroExError } from '../types';
-import { assert } from '../utils/assert';
-
-const DEFAULT_EVENT_POLLING_INTERVAL_MS = 200;
-
-enum LogEventState {
-    Removed,
-    Added,
-}
-
-/**
- * The EventWatcher watches for blockchain events at the specified block confirmation
- * depth.
- */
-export class EventWatcher {
-    private _web3Wrapper: Web3Wrapper;
-    private _pollingIntervalMs: number;
-    private _intervalIdIfExists?: NodeJS.Timer;
-    private _lastEvents: LogEntry[] = [];
-    private _stateLayer: BlockParamLiteral;
-    constructor(
-        web3Wrapper: Web3Wrapper,
-        pollingIntervalIfExistsMs: undefined | number,
-        stateLayer: BlockParamLiteral = BlockParamLiteral.Latest,
-    ) {
-        this._web3Wrapper = web3Wrapper;
-        this._stateLayer = stateLayer;
-        this._pollingIntervalMs = _.isUndefined(pollingIntervalIfExistsMs)
-            ? DEFAULT_EVENT_POLLING_INTERVAL_MS
-            : pollingIntervalIfExistsMs;
-    }
-    public subscribe(callback: EventWatcherCallback): void {
-        assert.isFunction('callback', callback);
-        if (!_.isUndefined(this._intervalIdIfExists)) {
-            throw new Error(ZeroExError.SubscriptionAlreadyPresent);
-        }
-        this._intervalIdIfExists = intervalUtils.setAsyncExcludingInterval(
-            this._pollForBlockchainEventsAsync.bind(this, callback),
-            this._pollingIntervalMs,
-            (err: Error) => {
-                this.unsubscribe();
-                callback(err);
-            },
-        );
-    }
-    public unsubscribe(): void {
-        this._lastEvents = [];
-        if (!_.isUndefined(this._intervalIdIfExists)) {
-            intervalUtils.clearAsyncExcludingInterval(this._intervalIdIfExists);
-            delete this._intervalIdIfExists;
-        }
-    }
-    private async _pollForBlockchainEventsAsync(callback: EventWatcherCallback): Promise<void> {
-        const pendingEvents = await this._getEventsAsync();
-        if (_.isUndefined(pendingEvents)) {
-            // HACK: This should never happen, but happens frequently on CI due to a ganache bug
-            return;
-        }
-        if (pendingEvents.length === 0) {
-            // HACK: Sometimes when node rebuilds the pending block we get back the empty result.
-            // We don't want to emit a lot of removal events and bring them back after a couple of miliseconds,
-            // that's why we just ignore those cases.
-            return;
-        }
-        const removedEvents = _.differenceBy(this._lastEvents, pendingEvents, JSON.stringify);
-        const newEvents = _.differenceBy(pendingEvents, this._lastEvents, JSON.stringify);
-        await this._emitDifferencesAsync(removedEvents, LogEventState.Removed, callback);
-        await this._emitDifferencesAsync(newEvents, LogEventState.Added, callback);
-        this._lastEvents = pendingEvents;
-    }
-    private async _getEventsAsync(): Promise<LogEntry[]> {
-        const eventFilter = {
-            fromBlock: this._stateLayer,
-            toBlock: this._stateLayer,
-        };
-        const events = await this._web3Wrapper.getLogsAsync(eventFilter);
-        return events;
-    }
-    private async _emitDifferencesAsync(
-        logs: LogEntry[],
-        logEventState: LogEventState,
-        callback: EventWatcherCallback,
-    ): Promise<void> {
-        for (const log of logs) {
-            const logEvent = {
-                removed: logEventState === LogEventState.Removed,
-                ...log,
-            };
-            if (!_.isUndefined(this._intervalIdIfExists)) {
-                callback(null, logEvent);
-            }
-        }
-    }
-}
diff --git a/packages/0x.js/src/order_watcher/expiration_watcher.ts b/packages/0x.js/src/order_watcher/expiration_watcher.ts
deleted file mode 100644
index 27ec7107d..000000000
--- a/packages/0x.js/src/order_watcher/expiration_watcher.ts
+++ /dev/null
@@ -1,87 +0,0 @@
-import { BigNumber, intervalUtils } from '@0xproject/utils';
-import { RBTree } from 'bintrees';
-import * as _ from 'lodash';
-
-import { ZeroExError } from '../types';
-import { utils } from '../utils/utils';
-
-const DEFAULT_EXPIRATION_MARGIN_MS = 0;
-const DEFAULT_ORDER_EXPIRATION_CHECKING_INTERVAL_MS = 50;
-
-/**
- * This class includes the functionality to detect expired orders.
- * It stores them in a min heap by expiration time and checks for expired ones every `orderExpirationCheckingIntervalMs`
- */
-export class ExpirationWatcher {
-    private _orderHashByExpirationRBTree: RBTree<string>;
-    private _expiration: { [orderHash: string]: BigNumber } = {};
-    private _orderExpirationCheckingIntervalMs: number;
-    private _expirationMarginMs: number;
-    private _orderExpirationCheckingIntervalIdIfExists?: NodeJS.Timer;
-    constructor(expirationMarginIfExistsMs?: number, orderExpirationCheckingIntervalIfExistsMs?: number) {
-        this._expirationMarginMs = expirationMarginIfExistsMs || DEFAULT_EXPIRATION_MARGIN_MS;
-        this._orderExpirationCheckingIntervalMs =
-            expirationMarginIfExistsMs || DEFAULT_ORDER_EXPIRATION_CHECKING_INTERVAL_MS;
-        const comparator = (lhsOrderHash: string, rhsOrderHash: string) => {
-            const lhsExpiration = this._expiration[lhsOrderHash].toNumber();
-            const rhsExpiration = this._expiration[rhsOrderHash].toNumber();
-            if (lhsExpiration !== rhsExpiration) {
-                return lhsExpiration - rhsExpiration;
-            } else {
-                // HACK: If two orders have identical expirations, the order in which they are emitted by the
-                // ExpirationWatcher does not matter, so we emit them in alphabetical order by orderHash.
-                return lhsOrderHash.localeCompare(rhsOrderHash);
-            }
-        };
-        this._orderHashByExpirationRBTree = new RBTree(comparator);
-    }
-    public subscribe(callback: (orderHash: string) => void): void {
-        if (!_.isUndefined(this._orderExpirationCheckingIntervalIdIfExists)) {
-            throw new Error(ZeroExError.SubscriptionAlreadyPresent);
-        }
-        this._orderExpirationCheckingIntervalIdIfExists = intervalUtils.setInterval(
-            this._pruneExpiredOrders.bind(this, callback),
-            this._orderExpirationCheckingIntervalMs,
-            _.noop, // _pruneExpiredOrders never throws
-        );
-    }
-    public unsubscribe(): void {
-        if (_.isUndefined(this._orderExpirationCheckingIntervalIdIfExists)) {
-            throw new Error(ZeroExError.SubscriptionNotFound);
-        }
-        intervalUtils.clearInterval(this._orderExpirationCheckingIntervalIdIfExists);
-        delete this._orderExpirationCheckingIntervalIdIfExists;
-    }
-    public addOrder(orderHash: string, expirationUnixTimestampMs: BigNumber): void {
-        this._expiration[orderHash] = expirationUnixTimestampMs;
-        this._orderHashByExpirationRBTree.insert(orderHash);
-    }
-    public removeOrder(orderHash: string): void {
-        if (_.isUndefined(this._expiration[orderHash])) {
-            return; // noop since order already removed
-        }
-        this._orderHashByExpirationRBTree.remove(orderHash);
-        delete this._expiration[orderHash];
-    }
-    private _pruneExpiredOrders(callback: (orderHash: string) => void): void {
-        const currentUnixTimestampMs = utils.getCurrentUnixTimestampMs();
-        while (true) {
-            const hasTrakedOrders = this._orderHashByExpirationRBTree.size === 0;
-            if (hasTrakedOrders) {
-                break;
-            }
-            const nextOrderHashToExpire = this._orderHashByExpirationRBTree.min();
-            const hasNoExpiredOrders = this._expiration[nextOrderHashToExpire].greaterThan(
-                currentUnixTimestampMs.plus(this._expirationMarginMs),
-            );
-            const isSubscriptionActive = _.isUndefined(this._orderExpirationCheckingIntervalIdIfExists);
-            if (hasNoExpiredOrders || isSubscriptionActive) {
-                break;
-            }
-            const orderHash = this._orderHashByExpirationRBTree.min();
-            this._orderHashByExpirationRBTree.remove(orderHash);
-            delete this._expiration[orderHash];
-            callback(orderHash);
-        }
-    }
-}
diff --git a/packages/0x.js/src/order_watcher/order_state_watcher.ts b/packages/0x.js/src/order_watcher/order_state_watcher.ts
deleted file mode 100644
index a9df8ac9d..000000000
--- a/packages/0x.js/src/order_watcher/order_state_watcher.ts
+++ /dev/null
@@ -1,381 +0,0 @@
-import { schemas } from '@0xproject/json-schemas';
-import { BlockParamLiteral, LogWithDecodedArgs, SignedOrder } from '@0xproject/types';
-import { AbiDecoder, intervalUtils } from '@0xproject/utils';
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
-import * as _ from 'lodash';
-
-import { ZeroEx } from '../0x';
-import { ExchangeWrapper } from '../contract_wrappers/exchange_wrapper';
-import {
-    DepositContractEventArgs,
-    EtherTokenEvents,
-    WithdrawalContractEventArgs,
-} from '../contract_wrappers/generated/ether_token';
-import {
-    ExchangeEvents,
-    LogCancelContractEventArgs,
-    LogFillContractEventArgs,
-} from '../contract_wrappers/generated/exchange';
-import {
-    ApprovalContractEventArgs,
-    TokenEvents,
-    TransferContractEventArgs,
-} from '../contract_wrappers/generated/token';
-import { TokenWrapper } from '../contract_wrappers/token_wrapper';
-import { BalanceAndProxyAllowanceLazyStore } from '../stores/balance_proxy_allowance_lazy_store';
-import { OrderFilledCancelledLazyStore } from '../stores/order_filled_cancelled_lazy_store';
-import {
-    ContractEventArgs,
-    ExchangeContractErrs,
-    LogEvent,
-    OnOrderStateChangeCallback,
-    OrderState,
-    OrderStateWatcherConfig,
-    ZeroExError,
-} from '../types';
-import { assert } from '../utils/assert';
-import { OrderStateUtils } from '../utils/order_state_utils';
-import { utils } from '../utils/utils';
-
-import { EventWatcher } from './event_watcher';
-import { ExpirationWatcher } from './expiration_watcher';
-
-interface DependentOrderHashes {
-    [makerAddress: string]: {
-        [makerToken: string]: Set<string>;
-    };
-}
-
-interface OrderByOrderHash {
-    [orderHash: string]: SignedOrder;
-}
-
-interface OrderStateByOrderHash {
-    [orderHash: string]: OrderState;
-}
-
-const DEFAULT_CLEANUP_JOB_INTERVAL_MS = 1000 * 60 * 60; // 1h
-
-/**
- * This class includes all the functionality related to watching a set of orders
- * for potential changes in order validity/fillability. The orderWatcher notifies
- * the subscriber of these changes so that a final decision can be made on whether
- * the order should be deemed invalid.
- */
-export class OrderStateWatcher {
-    private _orderStateByOrderHashCache: OrderStateByOrderHash = {};
-    private _orderByOrderHash: OrderByOrderHash = {};
-    private _dependentOrderHashes: DependentOrderHashes = {};
-    private _callbackIfExists?: OnOrderStateChangeCallback;
-    private _eventWatcher: EventWatcher;
-    private _web3Wrapper: Web3Wrapper;
-    private _expirationWatcher: ExpirationWatcher;
-    private _orderStateUtils: OrderStateUtils;
-    private _orderFilledCancelledLazyStore: OrderFilledCancelledLazyStore;
-    private _balanceAndProxyAllowanceLazyStore: BalanceAndProxyAllowanceLazyStore;
-    private _cleanupJobInterval: number;
-    private _cleanupJobIntervalIdIfExists?: NodeJS.Timer;
-    constructor(
-        web3Wrapper: Web3Wrapper,
-        token: TokenWrapper,
-        exchange: ExchangeWrapper,
-        config?: OrderStateWatcherConfig,
-    ) {
-        this._web3Wrapper = web3Wrapper;
-        const pollingIntervalIfExistsMs = _.isUndefined(config) ? undefined : config.eventPollingIntervalMs;
-        const stateLayer =
-            _.isUndefined(config) || _.isUndefined(config.stateLayer) ? BlockParamLiteral.Latest : config.stateLayer;
-        this._eventWatcher = new EventWatcher(web3Wrapper, pollingIntervalIfExistsMs, stateLayer);
-        this._balanceAndProxyAllowanceLazyStore = new BalanceAndProxyAllowanceLazyStore(token, stateLayer);
-        this._orderFilledCancelledLazyStore = new OrderFilledCancelledLazyStore(exchange, stateLayer);
-        this._orderStateUtils = new OrderStateUtils(
-            this._balanceAndProxyAllowanceLazyStore,
-            this._orderFilledCancelledLazyStore,
-        );
-        const orderExpirationCheckingIntervalMsIfExists = _.isUndefined(config)
-            ? undefined
-            : config.orderExpirationCheckingIntervalMs;
-        const expirationMarginIfExistsMs = _.isUndefined(config) ? undefined : config.expirationMarginMs;
-        this._expirationWatcher = new ExpirationWatcher(
-            expirationMarginIfExistsMs,
-            orderExpirationCheckingIntervalMsIfExists,
-        );
-        this._cleanupJobInterval =
-            _.isUndefined(config) || _.isUndefined(config.cleanupJobIntervalMs)
-                ? DEFAULT_CLEANUP_JOB_INTERVAL_MS
-                : config.cleanupJobIntervalMs;
-    }
-    /**
-     * Add an order to the orderStateWatcher. Before the order is added, it's
-     * signature is verified.
-     * @param   signedOrder     The order you wish to start watching.
-     */
-    public addOrder(signedOrder: SignedOrder): void {
-        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
-        const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-        assert.isValidSignature(orderHash, signedOrder.ecSignature, signedOrder.maker);
-        this._orderByOrderHash[orderHash] = signedOrder;
-        this._addToDependentOrderHashes(signedOrder, orderHash);
-        const expirationUnixTimestampMs = signedOrder.expirationUnixTimestampSec.times(1000);
-        this._expirationWatcher.addOrder(orderHash, expirationUnixTimestampMs);
-    }
-    /**
-     * Removes an order from the orderStateWatcher
-     * @param   orderHash     The orderHash of the order you wish to stop watching.
-     */
-    public removeOrder(orderHash: string): void {
-        assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
-        const signedOrder = this._orderByOrderHash[orderHash];
-        if (_.isUndefined(signedOrder)) {
-            return; // noop
-        }
-        delete this._orderByOrderHash[orderHash];
-        delete this._orderStateByOrderHashCache[orderHash];
-        const exchange = (this._orderFilledCancelledLazyStore as any)._exchangeWrapper as ExchangeWrapper;
-        const zrxTokenAddress = exchange.getZRXTokenAddress();
-
-        this._removeFromDependentOrderHashes(signedOrder.maker, zrxTokenAddress, orderHash);
-        if (zrxTokenAddress !== signedOrder.makerTokenAddress) {
-            this._removeFromDependentOrderHashes(signedOrder.maker, signedOrder.makerTokenAddress, orderHash);
-        }
-
-        this._expirationWatcher.removeOrder(orderHash);
-    }
-    /**
-     * Starts an orderStateWatcher subscription. The callback will be called every time a watched order's
-     * backing blockchain state has changed. This is a call-to-action for the caller to re-validate the order.
-     * @param   callback            Receives the orderHash of the order that should be re-validated, together
-     *                              with all the order-relevant blockchain state needed to re-validate the order.
-     */
-    public subscribe(callback: OnOrderStateChangeCallback): void {
-        assert.isFunction('callback', callback);
-        if (!_.isUndefined(this._callbackIfExists)) {
-            throw new Error(ZeroExError.SubscriptionAlreadyPresent);
-        }
-        this._callbackIfExists = callback;
-        this._eventWatcher.subscribe(this._onEventWatcherCallbackAsync.bind(this));
-        this._expirationWatcher.subscribe(this._onOrderExpired.bind(this));
-        this._cleanupJobIntervalIdIfExists = intervalUtils.setAsyncExcludingInterval(
-            this._cleanupAsync.bind(this),
-            this._cleanupJobInterval,
-            (err: Error) => {
-                this.unsubscribe();
-                callback(err);
-            },
-        );
-    }
-    /**
-     * Ends an orderStateWatcher subscription.
-     */
-    public unsubscribe(): void {
-        if (_.isUndefined(this._callbackIfExists) || _.isUndefined(this._cleanupJobIntervalIdIfExists)) {
-            throw new Error(ZeroExError.SubscriptionNotFound);
-        }
-        this._balanceAndProxyAllowanceLazyStore.deleteAll();
-        this._orderFilledCancelledLazyStore.deleteAll();
-        delete this._callbackIfExists;
-        this._eventWatcher.unsubscribe();
-        this._expirationWatcher.unsubscribe();
-        intervalUtils.clearAsyncExcludingInterval(this._cleanupJobIntervalIdIfExists);
-    }
-    private async _cleanupAsync(): Promise<void> {
-        for (const orderHash of _.keys(this._orderByOrderHash)) {
-            this._cleanupOrderRelatedState(orderHash);
-            await this._emitRevalidateOrdersAsync([orderHash]);
-        }
-    }
-    private _cleanupOrderRelatedState(orderHash: string): void {
-        const signedOrder = this._orderByOrderHash[orderHash];
-
-        this._orderFilledCancelledLazyStore.deleteFilledTakerAmount(orderHash);
-        this._orderFilledCancelledLazyStore.deleteCancelledTakerAmount(orderHash);
-
-        this._balanceAndProxyAllowanceLazyStore.deleteBalance(signedOrder.makerTokenAddress, signedOrder.maker);
-        this._balanceAndProxyAllowanceLazyStore.deleteProxyAllowance(signedOrder.makerTokenAddress, signedOrder.maker);
-        this._balanceAndProxyAllowanceLazyStore.deleteBalance(signedOrder.takerTokenAddress, signedOrder.taker);
-        this._balanceAndProxyAllowanceLazyStore.deleteProxyAllowance(signedOrder.takerTokenAddress, signedOrder.taker);
-
-        const zrxTokenAddress = this._getZRXTokenAddress();
-        if (!signedOrder.makerFee.isZero()) {
-            this._balanceAndProxyAllowanceLazyStore.deleteBalance(zrxTokenAddress, signedOrder.maker);
-            this._balanceAndProxyAllowanceLazyStore.deleteProxyAllowance(zrxTokenAddress, signedOrder.maker);
-        }
-        if (!signedOrder.takerFee.isZero()) {
-            this._balanceAndProxyAllowanceLazyStore.deleteBalance(zrxTokenAddress, signedOrder.taker);
-            this._balanceAndProxyAllowanceLazyStore.deleteProxyAllowance(zrxTokenAddress, signedOrder.taker);
-        }
-    }
-    private _onOrderExpired(orderHash: string): void {
-        const orderState: OrderState = {
-            isValid: false,
-            orderHash,
-            error: ExchangeContractErrs.OrderFillExpired,
-        };
-        if (!_.isUndefined(this._orderByOrderHash[orderHash])) {
-            this.removeOrder(orderHash);
-            if (!_.isUndefined(this._callbackIfExists)) {
-                this._callbackIfExists(null, orderState);
-            }
-        }
-    }
-    private async _onEventWatcherCallbackAsync(err: Error | null, logIfExists?: LogEvent): Promise<void> {
-        if (!_.isNull(err)) {
-            if (!_.isUndefined(this._callbackIfExists)) {
-                this._callbackIfExists(err);
-                this.unsubscribe();
-            }
-            return;
-        }
-        const log = logIfExists as LogEvent; // At this moment we are sure that no error occured and log is defined.
-        const maybeDecodedLog = this._web3Wrapper.abiDecoder.tryToDecodeLogOrNoop<ContractEventArgs>(log);
-        const isLogDecoded = !_.isUndefined(((maybeDecodedLog as any) as LogWithDecodedArgs<ContractEventArgs>).event);
-        if (!isLogDecoded) {
-            return; // noop
-        }
-        const decodedLog = (maybeDecodedLog as any) as LogWithDecodedArgs<ContractEventArgs>;
-        let makerToken: string;
-        let makerAddress: string;
-        switch (decodedLog.event) {
-            case TokenEvents.Approval: {
-                // Invalidate cache
-                const args = decodedLog.args as ApprovalContractEventArgs;
-                this._balanceAndProxyAllowanceLazyStore.deleteProxyAllowance(decodedLog.address, args._owner);
-                // Revalidate orders
-                makerToken = decodedLog.address;
-                makerAddress = args._owner;
-                if (
-                    !_.isUndefined(this._dependentOrderHashes[makerAddress]) &&
-                    !_.isUndefined(this._dependentOrderHashes[makerAddress][makerToken])
-                ) {
-                    const orderHashes = Array.from(this._dependentOrderHashes[makerAddress][makerToken]);
-                    await this._emitRevalidateOrdersAsync(orderHashes);
-                }
-                break;
-            }
-            case TokenEvents.Transfer: {
-                // Invalidate cache
-                const args = decodedLog.args as TransferContractEventArgs;
-                this._balanceAndProxyAllowanceLazyStore.deleteBalance(decodedLog.address, args._from);
-                this._balanceAndProxyAllowanceLazyStore.deleteBalance(decodedLog.address, args._to);
-                // Revalidate orders
-                makerToken = decodedLog.address;
-                makerAddress = args._from;
-                if (
-                    !_.isUndefined(this._dependentOrderHashes[makerAddress]) &&
-                    !_.isUndefined(this._dependentOrderHashes[makerAddress][makerToken])
-                ) {
-                    const orderHashes = Array.from(this._dependentOrderHashes[makerAddress][makerToken]);
-                    await this._emitRevalidateOrdersAsync(orderHashes);
-                }
-                break;
-            }
-            case EtherTokenEvents.Deposit: {
-                // Invalidate cache
-                const args = decodedLog.args as DepositContractEventArgs;
-                this._balanceAndProxyAllowanceLazyStore.deleteBalance(decodedLog.address, args._owner);
-                // Revalidate orders
-                makerToken = decodedLog.address;
-                makerAddress = args._owner;
-                if (
-                    !_.isUndefined(this._dependentOrderHashes[makerAddress]) &&
-                    !_.isUndefined(this._dependentOrderHashes[makerAddress][makerToken])
-                ) {
-                    const orderHashes = Array.from(this._dependentOrderHashes[makerAddress][makerToken]);
-                    await this._emitRevalidateOrdersAsync(orderHashes);
-                }
-                break;
-            }
-            case EtherTokenEvents.Withdrawal: {
-                // Invalidate cache
-                const args = decodedLog.args as WithdrawalContractEventArgs;
-                this._balanceAndProxyAllowanceLazyStore.deleteBalance(decodedLog.address, args._owner);
-                // Revalidate orders
-                makerToken = decodedLog.address;
-                makerAddress = args._owner;
-                if (
-                    !_.isUndefined(this._dependentOrderHashes[makerAddress]) &&
-                    !_.isUndefined(this._dependentOrderHashes[makerAddress][makerToken])
-                ) {
-                    const orderHashes = Array.from(this._dependentOrderHashes[makerAddress][makerToken]);
-                    await this._emitRevalidateOrdersAsync(orderHashes);
-                }
-                break;
-            }
-            case ExchangeEvents.LogFill: {
-                // Invalidate cache
-                const args = decodedLog.args as LogFillContractEventArgs;
-                this._orderFilledCancelledLazyStore.deleteFilledTakerAmount(args.orderHash);
-                // Revalidate orders
-                const orderHash = args.orderHash;
-                const isOrderWatched = !_.isUndefined(this._orderByOrderHash[orderHash]);
-                if (isOrderWatched) {
-                    await this._emitRevalidateOrdersAsync([orderHash]);
-                }
-                break;
-            }
-            case ExchangeEvents.LogCancel: {
-                // Invalidate cache
-                const args = decodedLog.args as LogCancelContractEventArgs;
-                this._orderFilledCancelledLazyStore.deleteCancelledTakerAmount(args.orderHash);
-                // Revalidate orders
-                const orderHash = args.orderHash;
-                const isOrderWatched = !_.isUndefined(this._orderByOrderHash[orderHash]);
-                if (isOrderWatched) {
-                    await this._emitRevalidateOrdersAsync([orderHash]);
-                }
-                break;
-            }
-            case ExchangeEvents.LogError:
-                return; // noop
-
-            default:
-                throw utils.spawnSwitchErr('decodedLog.event', decodedLog.event);
-        }
-    }
-    private async _emitRevalidateOrdersAsync(orderHashes: string[]): Promise<void> {
-        for (const orderHash of orderHashes) {
-            const signedOrder = this._orderByOrderHash[orderHash];
-            // Most of these calls will never reach the network because the data is fetched from stores
-            // and only updated when cache is invalidated
-            const orderState = await this._orderStateUtils.getOrderStateAsync(signedOrder);
-            if (_.isUndefined(this._callbackIfExists)) {
-                break; // Unsubscribe was called
-            }
-            if (_.isEqual(orderState, this._orderStateByOrderHashCache[orderHash])) {
-                // Actual order state didn't change
-                continue;
-            } else {
-                this._orderStateByOrderHashCache[orderHash] = orderState;
-            }
-            this._callbackIfExists(null, orderState);
-        }
-    }
-    private _addToDependentOrderHashes(signedOrder: SignedOrder, orderHash: string): void {
-        if (_.isUndefined(this._dependentOrderHashes[signedOrder.maker])) {
-            this._dependentOrderHashes[signedOrder.maker] = {};
-        }
-        if (_.isUndefined(this._dependentOrderHashes[signedOrder.maker][signedOrder.makerTokenAddress])) {
-            this._dependentOrderHashes[signedOrder.maker][signedOrder.makerTokenAddress] = new Set();
-        }
-        this._dependentOrderHashes[signedOrder.maker][signedOrder.makerTokenAddress].add(orderHash);
-        const zrxTokenAddress = this._getZRXTokenAddress();
-        if (_.isUndefined(this._dependentOrderHashes[signedOrder.maker][zrxTokenAddress])) {
-            this._dependentOrderHashes[signedOrder.maker][zrxTokenAddress] = new Set();
-        }
-        this._dependentOrderHashes[signedOrder.maker][zrxTokenAddress].add(orderHash);
-    }
-    private _removeFromDependentOrderHashes(makerAddress: string, tokenAddress: string, orderHash: string) {
-        this._dependentOrderHashes[makerAddress][tokenAddress].delete(orderHash);
-        if (this._dependentOrderHashes[makerAddress][tokenAddress].size === 0) {
-            delete this._dependentOrderHashes[makerAddress][tokenAddress];
-        }
-        if (_.isEmpty(this._dependentOrderHashes[makerAddress])) {
-            delete this._dependentOrderHashes[makerAddress];
-        }
-    }
-    private _getZRXTokenAddress(): string {
-        const exchange = (this._orderFilledCancelledLazyStore as any)._exchangeWrapper as ExchangeWrapper;
-        const zrxTokenAddress = exchange.getZRXTokenAddress();
-        return zrxTokenAddress;
-    }
-}
diff --git a/packages/0x.js/src/order_watcher/remaining_fillable_calculator.ts b/packages/0x.js/src/order_watcher/remaining_fillable_calculator.ts
deleted file mode 100644
index 184c13aa4..000000000
--- a/packages/0x.js/src/order_watcher/remaining_fillable_calculator.ts
+++ /dev/null
@@ -1,95 +0,0 @@
-import { SignedOrder } from '@0xproject/types';
-import { BigNumber } from '@0xproject/utils';
-
-export class RemainingFillableCalculator {
-    private _signedOrder: SignedOrder;
-    private _isMakerTokenZRX: boolean;
-    // Transferrable Amount is the minimum of Approval and Balance
-    private _transferrableMakerTokenAmount: BigNumber;
-    private _transferrableMakerFeeTokenAmount: BigNumber;
-    private _remainingMakerTokenAmount: BigNumber;
-    private _remainingMakerFeeAmount: BigNumber;
-    constructor(
-        signedOrder: SignedOrder,
-        isMakerTokenZRX: boolean,
-        transferrableMakerTokenAmount: BigNumber,
-        transferrableMakerFeeTokenAmount: BigNumber,
-        remainingMakerTokenAmount: BigNumber,
-    ) {
-        this._signedOrder = signedOrder;
-        this._isMakerTokenZRX = isMakerTokenZRX;
-        this._transferrableMakerTokenAmount = transferrableMakerTokenAmount;
-        this._transferrableMakerFeeTokenAmount = transferrableMakerFeeTokenAmount;
-        this._remainingMakerTokenAmount = remainingMakerTokenAmount;
-        this._remainingMakerFeeAmount = remainingMakerTokenAmount
-            .times(signedOrder.makerFee)
-            .dividedToIntegerBy(signedOrder.makerTokenAmount);
-    }
-    public computeRemainingMakerFillable(): BigNumber {
-        if (this._hasSufficientFundsForFeeAndTransferAmount()) {
-            return this._remainingMakerTokenAmount;
-        }
-        if (this._signedOrder.makerFee.isZero()) {
-            return BigNumber.min(this._remainingMakerTokenAmount, this._transferrableMakerTokenAmount);
-        }
-        return this._calculatePartiallyFillableMakerTokenAmount();
-    }
-    public computeRemainingTakerFillable(): BigNumber {
-        return this.computeRemainingMakerFillable()
-            .times(this._signedOrder.takerTokenAmount)
-            .dividedToIntegerBy(this._signedOrder.makerTokenAmount);
-    }
-    private _hasSufficientFundsForFeeAndTransferAmount(): boolean {
-        if (this._isMakerTokenZRX) {
-            const totalZRXTransferAmountRequired = this._remainingMakerTokenAmount.plus(this._remainingMakerFeeAmount);
-            const hasSufficientFunds = this._transferrableMakerTokenAmount.greaterThanOrEqualTo(
-                totalZRXTransferAmountRequired,
-            );
-            return hasSufficientFunds;
-        } else {
-            const hasSufficientFundsForTransferAmount = this._transferrableMakerTokenAmount.greaterThanOrEqualTo(
-                this._remainingMakerTokenAmount,
-            );
-            const hasSufficientFundsForFeeAmount = this._transferrableMakerFeeTokenAmount.greaterThanOrEqualTo(
-                this._remainingMakerFeeAmount,
-            );
-            const hasSufficientFunds = hasSufficientFundsForTransferAmount && hasSufficientFundsForFeeAmount;
-            return hasSufficientFunds;
-        }
-    }
-    private _calculatePartiallyFillableMakerTokenAmount(): BigNumber {
-        // Given an order for 200 wei for 2 ZRXwei fee, find 100 wei for 1 ZRXwei. Order ratio is then 100:1
-        const orderToFeeRatio = this._signedOrder.makerTokenAmount.dividedBy(this._signedOrder.makerFee);
-        // The number of times the maker can fill the order, if each fill only required the transfer of a single
-        // baseUnit of fee tokens.
-        // Given 2 ZRXwei, the maximum amount of times Maker can fill this order, in terms of fees, is 2
-        const fillableTimesInFeeTokenBaseUnits = BigNumber.min(
-            this._transferrableMakerFeeTokenAmount,
-            this._remainingMakerFeeAmount,
-        );
-        // The number of times the Maker can fill the order, given the Maker Token Balance
-        // Assuming a balance of 150 wei, and an orderToFeeRatio of 100:1, maker can fill this order 1 time.
-        let fillableTimesInMakerTokenUnits = this._transferrableMakerTokenAmount.dividedBy(orderToFeeRatio);
-        if (this._isMakerTokenZRX) {
-            // If ZRX is the maker token, the Fee and the Maker amount need to be removed from the same pool;
-            // 200 ZRXwei for 2ZRXwei fee can only be filled once (need 202 ZRXwei)
-            const totalZRXTokenPooled = this._transferrableMakerTokenAmount;
-            // The purchasing power here is less as the tokens are taken from the same Pool
-            // For every one number of fills, we have to take an extra ZRX out of the pool
-            fillableTimesInMakerTokenUnits = totalZRXTokenPooled.dividedBy(orderToFeeRatio.plus(new BigNumber(1)));
-        }
-        // When Ratio is not fully divisible there can be remainders which cannot be represented, so they are floored.
-        // This can result in a RoundingError being thrown by the Exchange Contract.
-        const partiallyFillableMakerTokenAmount = fillableTimesInMakerTokenUnits
-            .times(this._signedOrder.makerTokenAmount)
-            .dividedToIntegerBy(this._signedOrder.makerFee);
-        const partiallyFillableFeeTokenAmount = fillableTimesInFeeTokenBaseUnits
-            .times(this._signedOrder.makerTokenAmount)
-            .dividedToIntegerBy(this._signedOrder.makerFee);
-        const partiallyFillableAmount = BigNumber.min(
-            partiallyFillableMakerTokenAmount,
-            partiallyFillableFeeTokenAmount,
-        );
-        return partiallyFillableAmount;
-    }
-}
diff --git a/packages/0x.js/src/stores/balance_proxy_allowance_lazy_store.ts b/packages/0x.js/src/stores/balance_proxy_allowance_lazy_store.ts
deleted file mode 100644
index 3ff116db4..000000000
--- a/packages/0x.js/src/stores/balance_proxy_allowance_lazy_store.ts
+++ /dev/null
@@ -1,91 +0,0 @@
-import { BlockParamLiteral } from '@0xproject/types';
-import { BigNumber } from '@0xproject/utils';
-import * as _ from 'lodash';
-
-import { BalanceAndProxyAllowanceFetcher } from '../abstract/balance_and_proxy_allowance_fetcher';
-import { TokenWrapper } from '../contract_wrappers/token_wrapper';
-
-/**
- * Copy on read store for balances/proxyAllowances of tokens/accounts
- */
-export class BalanceAndProxyAllowanceLazyStore implements BalanceAndProxyAllowanceFetcher {
-    private _tokenWrapper: TokenWrapper;
-    private _defaultBlock: BlockParamLiteral;
-    private _balance: {
-        [tokenAddress: string]: {
-            [userAddress: string]: BigNumber;
-        };
-    };
-    private _proxyAllowance: {
-        [tokenAddress: string]: {
-            [userAddress: string]: BigNumber;
-        };
-    };
-    constructor(token: TokenWrapper, defaultBlock: BlockParamLiteral) {
-        this._tokenWrapper = token;
-        this._defaultBlock = defaultBlock;
-        this._balance = {};
-        this._proxyAllowance = {};
-    }
-    public async getBalanceAsync(tokenAddress: string, userAddress: string): Promise<BigNumber> {
-        if (_.isUndefined(this._balance[tokenAddress]) || _.isUndefined(this._balance[tokenAddress][userAddress])) {
-            const methodOpts = {
-                defaultBlock: this._defaultBlock,
-            };
-            const balance = await this._tokenWrapper.getBalanceAsync(tokenAddress, userAddress, methodOpts);
-            this.setBalance(tokenAddress, userAddress, balance);
-        }
-        const cachedBalance = this._balance[tokenAddress][userAddress];
-        return cachedBalance;
-    }
-    public setBalance(tokenAddress: string, userAddress: string, balance: BigNumber): void {
-        if (_.isUndefined(this._balance[tokenAddress])) {
-            this._balance[tokenAddress] = {};
-        }
-        this._balance[tokenAddress][userAddress] = balance;
-    }
-    public deleteBalance(tokenAddress: string, userAddress: string): void {
-        if (!_.isUndefined(this._balance[tokenAddress])) {
-            delete this._balance[tokenAddress][userAddress];
-            if (_.isEmpty(this._balance[tokenAddress])) {
-                delete this._balance[tokenAddress];
-            }
-        }
-    }
-    public async getProxyAllowanceAsync(tokenAddress: string, userAddress: string): Promise<BigNumber> {
-        if (
-            _.isUndefined(this._proxyAllowance[tokenAddress]) ||
-            _.isUndefined(this._proxyAllowance[tokenAddress][userAddress])
-        ) {
-            const methodOpts = {
-                defaultBlock: this._defaultBlock,
-            };
-            const proxyAllowance = await this._tokenWrapper.getProxyAllowanceAsync(
-                tokenAddress,
-                userAddress,
-                methodOpts,
-            );
-            this.setProxyAllowance(tokenAddress, userAddress, proxyAllowance);
-        }
-        const cachedProxyAllowance = this._proxyAllowance[tokenAddress][userAddress];
-        return cachedProxyAllowance;
-    }
-    public setProxyAllowance(tokenAddress: string, userAddress: string, proxyAllowance: BigNumber): void {
-        if (_.isUndefined(this._proxyAllowance[tokenAddress])) {
-            this._proxyAllowance[tokenAddress] = {};
-        }
-        this._proxyAllowance[tokenAddress][userAddress] = proxyAllowance;
-    }
-    public deleteProxyAllowance(tokenAddress: string, userAddress: string): void {
-        if (!_.isUndefined(this._proxyAllowance[tokenAddress])) {
-            delete this._proxyAllowance[tokenAddress][userAddress];
-            if (_.isEmpty(this._proxyAllowance[tokenAddress])) {
-                delete this._proxyAllowance[tokenAddress];
-            }
-        }
-    }
-    public deleteAll(): void {
-        this._balance = {};
-        this._proxyAllowance = {};
-    }
-}
diff --git a/packages/0x.js/src/stores/order_filled_cancelled_lazy_store.ts b/packages/0x.js/src/stores/order_filled_cancelled_lazy_store.ts
deleted file mode 100644
index 61d2db8c2..000000000
--- a/packages/0x.js/src/stores/order_filled_cancelled_lazy_store.ts
+++ /dev/null
@@ -1,67 +0,0 @@
-import { BlockParamLiteral } from '@0xproject/types';
-import { BigNumber } from '@0xproject/utils';
-import * as _ from 'lodash';
-
-import { OrderFilledCancelledFetcher } from '../abstract/order_filled_cancelled_fetcher';
-import { ExchangeWrapper } from '../contract_wrappers/exchange_wrapper';
-
-/**
- * Copy on read store for filled/cancelled taker amounts
- */
-export class OrderFilledCancelledLazyStore implements OrderFilledCancelledFetcher {
-    private _exchangeWrapper: ExchangeWrapper;
-    private _defaultBlock: BlockParamLiteral;
-    private _filledTakerAmount: {
-        [orderHash: string]: BigNumber;
-    };
-    private _cancelledTakerAmount: {
-        [orderHash: string]: BigNumber;
-    };
-    constructor(exchange: ExchangeWrapper, defaultBlock: BlockParamLiteral) {
-        this._exchangeWrapper = exchange;
-        this._defaultBlock = defaultBlock;
-        this._filledTakerAmount = {};
-        this._cancelledTakerAmount = {};
-    }
-    public async getFilledTakerAmountAsync(orderHash: string): Promise<BigNumber> {
-        if (_.isUndefined(this._filledTakerAmount[orderHash])) {
-            const methodOpts = {
-                defaultBlock: this._defaultBlock,
-            };
-            const filledTakerAmount = await this._exchangeWrapper.getFilledTakerAmountAsync(orderHash, methodOpts);
-            this.setFilledTakerAmount(orderHash, filledTakerAmount);
-        }
-        const cachedFilled = this._filledTakerAmount[orderHash];
-        return cachedFilled;
-    }
-    public setFilledTakerAmount(orderHash: string, filledTakerAmount: BigNumber): void {
-        this._filledTakerAmount[orderHash] = filledTakerAmount;
-    }
-    public deleteFilledTakerAmount(orderHash: string): void {
-        delete this._filledTakerAmount[orderHash];
-    }
-    public async getCancelledTakerAmountAsync(orderHash: string): Promise<BigNumber> {
-        if (_.isUndefined(this._cancelledTakerAmount[orderHash])) {
-            const methodOpts = {
-                defaultBlock: this._defaultBlock,
-            };
-            const cancelledTakerAmount = await this._exchangeWrapper.getCancelledTakerAmountAsync(
-                orderHash,
-                methodOpts,
-            );
-            this.setCancelledTakerAmount(orderHash, cancelledTakerAmount);
-        }
-        const cachedCancelled = this._cancelledTakerAmount[orderHash];
-        return cachedCancelled;
-    }
-    public setCancelledTakerAmount(orderHash: string, cancelledTakerAmount: BigNumber): void {
-        this._cancelledTakerAmount[orderHash] = cancelledTakerAmount;
-    }
-    public deleteCancelledTakerAmount(orderHash: string): void {
-        delete this._cancelledTakerAmount[orderHash];
-    }
-    public deleteAll(): void {
-        this._filledTakerAmount = {};
-        this._cancelledTakerAmount = {};
-    }
-}
diff --git a/packages/0x.js/src/types.ts b/packages/0x.js/src/types.ts
index ae9f98c5f..516bef8a3 100644
--- a/packages/0x.js/src/types.ts
+++ b/packages/0x.js/src/types.ts
@@ -1,23 +1,16 @@
-import { BigNumber } from '@0xproject/utils';
-
 import {
     BlockParam,
     BlockParamLiteral,
     ContractAbi,
     ContractEventArg,
+    ExchangeContractErrs,
     FilterObject,
-    LogEntryEvent,
     LogWithDecodedArgs,
     Order,
+    OrderState,
     SignedOrder,
 } from '@0xproject/types';
 
-import * as Web3 from 'web3';
-
-import { EtherTokenContractEventArgs, EtherTokenEvents } from './contract_wrappers/generated/ether_token';
-import { ExchangeContractEventArgs, ExchangeEvents } from './contract_wrappers/generated/exchange';
-import { TokenContractEventArgs, TokenEvents } from './contract_wrappers/generated/token';
-
 export enum ZeroExError {
     ExchangeContractDoesNotExist = 'EXCHANGE_CONTRACT_DOES_NOT_EXIST',
     ZRXContractDoesNotExist = 'ZRX_CONTRACT_DOES_NOT_EXIST',
@@ -45,232 +38,4 @@ export enum InternalZeroExError {
     WethNotInTokenRegistry = 'WETH_NOT_IN_TOKEN_REGISTRY',
 }
 
-export type OrderAddresses = [string, string, string, string, string];
-
-export type OrderValues = [BigNumber, BigNumber, BigNumber, BigNumber, BigNumber, BigNumber];
-
-export type LogEvent = LogEntryEvent;
-export interface DecodedLogEvent<ArgsType> {
-    isRemoved: boolean;
-    log: LogWithDecodedArgs<ArgsType>;
-}
-
-export type EventCallback<ArgsType> = (err: null | Error, log?: DecodedLogEvent<ArgsType>) => void;
-export type EventWatcherCallback = (err: null | Error, log?: LogEvent) => void;
-
-export enum ExchangeContractErrCodes {
-    ERROR_FILL_EXPIRED, // Order has already expired
-    ERROR_FILL_NO_VALUE, // Order has already been fully filled or cancelled
-    ERROR_FILL_TRUNCATION, // Rounding error too large
-    ERROR_FILL_BALANCE_ALLOWANCE, // Insufficient balance or allowance for token transfer
-    ERROR_CANCEL_EXPIRED, // Order has already expired
-    ERROR_CANCEL_NO_VALUE, // Order has already been fully filled or cancelled
-}
-
-export enum ExchangeContractErrs {
-    OrderFillExpired = 'ORDER_FILL_EXPIRED',
-    OrderCancelExpired = 'ORDER_CANCEL_EXPIRED',
-    OrderCancelAmountZero = 'ORDER_CANCEL_AMOUNT_ZERO',
-    OrderAlreadyCancelledOrFilled = 'ORDER_ALREADY_CANCELLED_OR_FILLED',
-    OrderFillAmountZero = 'ORDER_FILL_AMOUNT_ZERO',
-    OrderRemainingFillAmountZero = 'ORDER_REMAINING_FILL_AMOUNT_ZERO',
-    OrderFillRoundingError = 'ORDER_FILL_ROUNDING_ERROR',
-    FillBalanceAllowanceError = 'FILL_BALANCE_ALLOWANCE_ERROR',
-    InsufficientTakerBalance = 'INSUFFICIENT_TAKER_BALANCE',
-    InsufficientTakerAllowance = 'INSUFFICIENT_TAKER_ALLOWANCE',
-    InsufficientMakerBalance = 'INSUFFICIENT_MAKER_BALANCE',
-    InsufficientMakerAllowance = 'INSUFFICIENT_MAKER_ALLOWANCE',
-    InsufficientTakerFeeBalance = 'INSUFFICIENT_TAKER_FEE_BALANCE',
-    InsufficientTakerFeeAllowance = 'INSUFFICIENT_TAKER_FEE_ALLOWANCE',
-    InsufficientMakerFeeBalance = 'INSUFFICIENT_MAKER_FEE_BALANCE',
-    InsufficientMakerFeeAllowance = 'INSUFFICIENT_MAKER_FEE_ALLOWANCE',
-    TransactionSenderIsNotFillOrderTaker = 'TRANSACTION_SENDER_IS_NOT_FILL_ORDER_TAKER',
-    MultipleMakersInSingleCancelBatchDisallowed = 'MULTIPLE_MAKERS_IN_SINGLE_CANCEL_BATCH_DISALLOWED',
-    InsufficientRemainingFillAmount = 'INSUFFICIENT_REMAINING_FILL_AMOUNT',
-    MultipleTakerTokensInFillUpToDisallowed = 'MULTIPLE_TAKER_TOKENS_IN_FILL_UP_TO_DISALLOWED',
-    BatchOrdersMustHaveSameExchangeAddress = 'BATCH_ORDERS_MUST_HAVE_SAME_EXCHANGE_ADDRESS',
-    BatchOrdersMustHaveAtLeastOneItem = 'BATCH_ORDERS_MUST_HAVE_AT_LEAST_ONE_ITEM',
-}
-
-export interface ContractEvent {
-    logIndex: number;
-    transactionIndex: number;
-    transactionHash: string;
-    blockHash: string;
-    blockNumber: number;
-    address: string;
-    type: string;
-    event: string;
-    args: ContractEventArgs;
-}
-
-export type ContractEventArgs = ExchangeContractEventArgs | TokenContractEventArgs | EtherTokenContractEventArgs;
-
-//                          [address, name, symbol, decimals, ipfsHash, swarmHash]
-export type TokenMetadata = [string, string, string, number, string, string];
-
-export interface Token {
-    name: string;
-    address: string;
-    symbol: string;
-    decimals: number;
-}
-
-export interface TxOpts {
-    from: string;
-    gas?: number;
-    value?: BigNumber;
-    gasPrice?: BigNumber;
-}
-
-export interface TokenAddressBySymbol {
-    [symbol: string]: string;
-}
-
-export type ContractEvents = TokenEvents | ExchangeEvents | EtherTokenEvents;
-
-export interface IndexedFilterValues {
-    [index: string]: ContractEventArg;
-}
-
-export interface BlockRange {
-    fromBlock: BlockParam;
-    toBlock: BlockParam;
-}
-
-export type DoneCallback = (err?: Error) => void;
-
-export interface OrderCancellationRequest {
-    order: Order | SignedOrder;
-    takerTokenCancelAmount: BigNumber;
-}
-
-export interface OrderFillRequest {
-    signedOrder: SignedOrder;
-    takerTokenFillAmount: BigNumber;
-}
-
-export type AsyncMethod = (...args: any[]) => Promise<any>;
-export type SyncMethod = (...args: any[]) => any;
-
-/**
- * orderExpirationCheckingIntervalMs: How often to check for expired orders. Default=50.
- * eventPollingIntervalMs: How often to poll the Ethereum node for new events. Default=200.
- * expirationMarginMs: Amount of time before order expiry that you'd like to be notified
- * of an orders expiration. Default=0.
- * cleanupJobIntervalMs: How often to run a cleanup job which revalidates all the orders. Default=1hr.
- * stateLayer: Optional blockchain state layer OrderWatcher will monitor for new events. Default=latest.
- */
-export interface OrderStateWatcherConfig {
-    orderExpirationCheckingIntervalMs?: number;
-    eventPollingIntervalMs?: number;
-    expirationMarginMs?: number;
-    cleanupJobIntervalMs?: number;
-    stateLayer: BlockParamLiteral;
-}
-
-/**
- * networkId: The id of the underlying ethereum network your provider is connected to. (1-mainnet, 3-ropsten, 4-rinkeby, 42-kovan, 50-testrpc)
- * gasPrice: Gas price to use with every transaction
- * exchangeContractAddress: The address of an exchange contract to use
- * zrxContractAddress: The address of the ZRX contract to use
- * tokenRegistryContractAddress: The address of a token registry contract to use
- * tokenTransferProxyContractAddress: The address of the token transfer proxy contract to use
- * orderWatcherConfig: All the configs related to the orderWatcher
- */
-export interface ZeroExConfig {
-    networkId: number;
-    gasPrice?: BigNumber;
-    exchangeContractAddress?: string;
-    zrxContractAddress?: string;
-    tokenRegistryContractAddress?: string;
-    tokenTransferProxyContractAddress?: string;
-    orderWatcherConfig?: OrderStateWatcherConfig;
-}
-
-export type ArtifactContractName = 'ZRX' | 'TokenTransferProxy' | 'TokenRegistry' | 'Token' | 'Exchange' | 'EtherToken';
-
-export interface Artifact {
-    contract_name: ArtifactContractName;
-    abi: ContractAbi;
-    networks: {
-        [networkId: number]: {
-            address: string;
-        };
-    };
-}
-
-/**
- * expectedFillTakerTokenAmount: If specified, the validation method will ensure that the
- * supplied order maker has a sufficient allowance/balance to fill this amount of the order's
- * takerTokenAmount. If not specified, the validation method ensures that the maker has a sufficient
- * allowance/balance to fill the entire remaining order amount.
- */
-export interface ValidateOrderFillableOpts {
-    expectedFillTakerTokenAmount?: BigNumber;
-}
-
-/**
- * defaultBlock: The block up to which to query the blockchain state. Setting this to a historical block number
- * let's the user query the blockchain's state at an arbitrary point in time. In order for this to work, the
- * backing  Ethereum node must keep the entire historical state of the chain (e.g setting `--pruning=archive`
- * flag when  running Parity).
- */
-export interface MethodOpts {
-    defaultBlock?: BlockParam;
-}
-
-/**
- * gasPrice: Gas price in Wei to use for a transaction
- * gasLimit: The amount of gas to send with a transaction
- */
-export interface TransactionOpts {
-    gasPrice?: BigNumber;
-    gasLimit?: number;
-}
-
-/**
- * shouldValidate: Flag indicating whether the library should make attempts to validate a transaction before
- * broadcasting it. For example, order has a valid signature, maker has sufficient funds, etc. Default=true.
- */
-export interface OrderTransactionOpts extends TransactionOpts {
-    shouldValidate?: boolean;
-}
-
-export enum TradeSide {
-    Maker = 'maker',
-    Taker = 'taker',
-}
-
-export enum TransferType {
-    Trade = 'trade',
-    Fee = 'fee',
-}
-
-export interface OrderRelevantState {
-    makerBalance: BigNumber;
-    makerProxyAllowance: BigNumber;
-    makerFeeBalance: BigNumber;
-    makerFeeProxyAllowance: BigNumber;
-    filledTakerTokenAmount: BigNumber;
-    cancelledTakerTokenAmount: BigNumber;
-    remainingFillableMakerTokenAmount: BigNumber;
-    remainingFillableTakerTokenAmount: BigNumber;
-}
-
-export interface OrderStateValid {
-    isValid: true;
-    orderHash: string;
-    orderRelevantState: OrderRelevantState;
-}
-
-export interface OrderStateInvalid {
-    isValid: false;
-    orderHash: string;
-    error: ExchangeContractErrs;
-}
-
-export type OrderState = OrderStateValid | OrderStateInvalid;
-
-export type OnOrderStateChangeCallback = (err: Error | null, orderState?: OrderState) => void;
 // tslint:disable:max-file-line-count
diff --git a/packages/0x.js/src/utils/assert.ts b/packages/0x.js/src/utils/assert.ts
deleted file mode 100644
index 2588a4d09..000000000
--- a/packages/0x.js/src/utils/assert.ts
+++ /dev/null
@@ -1,31 +0,0 @@
-import { assert as sharedAssert } from '@0xproject/assert';
-// We need those two unused imports because they're actually used by sharedAssert which gets injected here
-// tslint:disable-next-line:no-unused-variable
-import { Schema } from '@0xproject/json-schemas';
-// tslint:disable-next-line:no-unused-variable
-import { ECSignature } from '@0xproject/types';
-import { BigNumber } from '@0xproject/utils';
-import { Web3Wrapper } from '@0xproject/web3-wrapper';
-import * as _ from 'lodash';
-
-import { isValidSignature } from '@0xproject/order-utils';
-
-export const assert = {
-    ...sharedAssert,
-    isValidSignature(orderHash: string, ecSignature: ECSignature, signerAddress: string) {
-        const isValid = isValidSignature(orderHash, ecSignature, signerAddress);
-        this.assert(isValid, `Expected order with hash '${orderHash}' to have a valid signature`);
-    },
-    async isSenderAddressAsync(
-        variableName: string,
-        senderAddressHex: string,
-        web3Wrapper: Web3Wrapper,
-    ): Promise<void> {
-        sharedAssert.isETHAddressHex(variableName, senderAddressHex);
-        const isSenderAddressAvailable = await web3Wrapper.isSenderAddressAvailableAsync(senderAddressHex);
-        sharedAssert.assert(
-            isSenderAddressAvailable,
-            `Specified ${variableName} ${senderAddressHex} isn't available through the supplied web3 provider`,
-        );
-    },
-};
diff --git a/packages/0x.js/src/utils/constants.ts b/packages/0x.js/src/utils/constants.ts
index 07da6745d..7cd5eb574 100644
--- a/packages/0x.js/src/utils/constants.ts
+++ b/packages/0x.js/src/utils/constants.ts
@@ -3,9 +3,4 @@ import { BigNumber } from '@0xproject/utils';
 export const constants = {
     NULL_ADDRESS: '0x0000000000000000000000000000000000000000',
     TESTRPC_NETWORK_ID: 50,
-    INVALID_JUMP_PATTERN: 'invalid JUMP at',
-    OUT_OF_GAS_PATTERN: 'out of gas',
-    INVALID_TAKER_FORMAT: 'instance.taker is not of a type(s) string',
-    UNLIMITED_ALLOWANCE_IN_BASE_UNITS: new BigNumber(2).pow(256).minus(1),
-    DEFAULT_BLOCK_POLLING_INTERVAL: 1000,
 };
diff --git a/packages/0x.js/src/utils/decorators.ts b/packages/0x.js/src/utils/decorators.ts
deleted file mode 100644
index f774d734e..000000000
--- a/packages/0x.js/src/utils/decorators.ts
+++ /dev/null
@@ -1,91 +0,0 @@
-import * as _ from 'lodash';
-
-import { AsyncMethod, SyncMethod, ZeroExError } from '../types';
-
-import { constants } from './constants';
-
-type ErrorTransformer = (err: Error) => Error;
-
-const contractCallErrorTransformer = (error: Error) => {
-    if (_.includes(error.message, constants.INVALID_JUMP_PATTERN)) {
-        return new Error(ZeroExError.InvalidJump);
-    }
-    if (_.includes(error.message, constants.OUT_OF_GAS_PATTERN)) {
-        return new Error(ZeroExError.OutOfGas);
-    }
-    return error;
-};
-
-const schemaErrorTransformer = (error: Error) => {
-    if (_.includes(error.message, constants.INVALID_TAKER_FORMAT)) {
-        const errMsg =
-            'Order taker must be of type string. If you want anyone to be able to fill an order - pass ZeroEx.NULL_ADDRESS';
-        return new Error(errMsg);
-    }
-    return error;
-};
-
-/**
- * Source: https://stackoverflow.com/a/29837695/3546986
- */
-const asyncErrorHandlerFactory = (errorTransformer: ErrorTransformer) => {
-    const asyncErrorHandlingDecorator = (
-        target: object,
-        key: string | symbol,
-        descriptor: TypedPropertyDescriptor<AsyncMethod>,
-    ) => {
-        const originalMethod = descriptor.value as AsyncMethod;
-
-        // Do not use arrow syntax here. Use a function expression in
-        // order to use the correct value of `this` in this method
-        // tslint:disable-next-line:only-arrow-functions
-        descriptor.value = async function(...args: any[]) {
-            try {
-                const result = await originalMethod.apply(this, args);
-                return result;
-            } catch (error) {
-                const transformedError = errorTransformer(error);
-                throw transformedError;
-            }
-        };
-
-        return descriptor;
-    };
-
-    return asyncErrorHandlingDecorator;
-};
-
-const syncErrorHandlerFactory = (errorTransformer: ErrorTransformer) => {
-    const syncErrorHandlingDecorator = (
-        target: object,
-        key: string | symbol,
-        descriptor: TypedPropertyDescriptor<SyncMethod>,
-    ) => {
-        const originalMethod = descriptor.value as SyncMethod;
-
-        // Do not use arrow syntax here. Use a function expression in
-        // order to use the correct value of `this` in this method
-        // tslint:disable-next-line:only-arrow-functions
-        descriptor.value = function(...args: any[]) {
-            try {
-                const result = originalMethod.apply(this, args);
-                return result;
-            } catch (error) {
-                const transformedError = errorTransformer(error);
-                throw transformedError;
-            }
-        };
-
-        return descriptor;
-    };
-
-    return syncErrorHandlingDecorator;
-};
-
-// _.flow(f, g) = f ∘ g
-const zeroExErrorTransformer = _.flow(schemaErrorTransformer, contractCallErrorTransformer);
-
-export const decorators = {
-    asyncZeroExErrorHandler: asyncErrorHandlerFactory(zeroExErrorTransformer),
-    syncZeroExErrorHandler: syncErrorHandlerFactory(zeroExErrorTransformer),
-};
diff --git a/packages/0x.js/src/utils/exchange_transfer_simulator.ts b/packages/0x.js/src/utils/exchange_transfer_simulator.ts
deleted file mode 100644
index f8301f5c2..000000000
--- a/packages/0x.js/src/utils/exchange_transfer_simulator.ts
+++ /dev/null
@@ -1,115 +0,0 @@
-import { BlockParamLiteral } from '@0xproject/types';
-import { BigNumber } from '@0xproject/utils';
-import * as _ from 'lodash';
-
-import { TokenWrapper } from '../contract_wrappers/token_wrapper';
-import { BalanceAndProxyAllowanceLazyStore } from '../stores/balance_proxy_allowance_lazy_store';
-import { ExchangeContractErrs, TradeSide, TransferType } from '../types';
-import { constants } from '../utils/constants';
-
-enum FailureReason {
-    Balance = 'balance',
-    ProxyAllowance = 'proxyAllowance',
-}
-
-const ERR_MSG_MAPPING = {
-    [FailureReason.Balance]: {
-        [TradeSide.Maker]: {
-            [TransferType.Trade]: ExchangeContractErrs.InsufficientMakerBalance,
-            [TransferType.Fee]: ExchangeContractErrs.InsufficientMakerFeeBalance,
-        },
-        [TradeSide.Taker]: {
-            [TransferType.Trade]: ExchangeContractErrs.InsufficientTakerBalance,
-            [TransferType.Fee]: ExchangeContractErrs.InsufficientTakerFeeBalance,
-        },
-    },
-    [FailureReason.ProxyAllowance]: {
-        [TradeSide.Maker]: {
-            [TransferType.Trade]: ExchangeContractErrs.InsufficientMakerAllowance,
-            [TransferType.Fee]: ExchangeContractErrs.InsufficientMakerFeeAllowance,
-        },
-        [TradeSide.Taker]: {
-            [TransferType.Trade]: ExchangeContractErrs.InsufficientTakerAllowance,
-            [TransferType.Fee]: ExchangeContractErrs.InsufficientTakerFeeAllowance,
-        },
-    },
-};
-
-export class ExchangeTransferSimulator {
-    private _store: BalanceAndProxyAllowanceLazyStore;
-    private _UNLIMITED_ALLOWANCE_IN_BASE_UNITS: BigNumber;
-    private static _throwValidationError(
-        failureReason: FailureReason,
-        tradeSide: TradeSide,
-        transferType: TransferType,
-    ): never {
-        const errMsg = ERR_MSG_MAPPING[failureReason][tradeSide][transferType];
-        throw new Error(errMsg);
-    }
-    constructor(token: TokenWrapper, defaultBlock: BlockParamLiteral) {
-        this._store = new BalanceAndProxyAllowanceLazyStore(token, defaultBlock);
-        this._UNLIMITED_ALLOWANCE_IN_BASE_UNITS = token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
-    }
-    /**
-     * Simulates transferFrom call performed by a proxy
-     * @param  tokenAddress      Address of the token to be transferred
-     * @param  from              Owner of the transferred tokens
-     * @param  to                Recipient of the transferred tokens
-     * @param  amountInBaseUnits The amount of tokens being transferred
-     * @param  tradeSide         Is Maker/Taker transferring
-     * @param  transferType      Is it a fee payment or a value transfer
-     */
-    public async transferFromAsync(
-        tokenAddress: string,
-        from: string,
-        to: string,
-        amountInBaseUnits: BigNumber,
-        tradeSide: TradeSide,
-        transferType: TransferType,
-    ): Promise<void> {
-        // HACK: When simulating an open order (e.g taker is NULL_ADDRESS), we don't want to adjust balances/
-        // allowances for the taker. We do however, want to increase the balance of the maker since the maker
-        // might be relying on those funds to fill subsequent orders or pay the order's fees.
-        if (from === constants.NULL_ADDRESS && tradeSide === TradeSide.Taker) {
-            await this._increaseBalanceAsync(tokenAddress, to, amountInBaseUnits);
-            return;
-        }
-        const balance = await this._store.getBalanceAsync(tokenAddress, from);
-        const proxyAllowance = await this._store.getProxyAllowanceAsync(tokenAddress, from);
-        if (proxyAllowance.lessThan(amountInBaseUnits)) {
-            ExchangeTransferSimulator._throwValidationError(FailureReason.ProxyAllowance, tradeSide, transferType);
-        }
-        if (balance.lessThan(amountInBaseUnits)) {
-            ExchangeTransferSimulator._throwValidationError(FailureReason.Balance, tradeSide, transferType);
-        }
-        await this._decreaseProxyAllowanceAsync(tokenAddress, from, amountInBaseUnits);
-        await this._decreaseBalanceAsync(tokenAddress, from, amountInBaseUnits);
-        await this._increaseBalanceAsync(tokenAddress, to, amountInBaseUnits);
-    }
-    private async _decreaseProxyAllowanceAsync(
-        tokenAddress: string,
-        userAddress: string,
-        amountInBaseUnits: BigNumber,
-    ): Promise<void> {
-        const proxyAllowance = await this._store.getProxyAllowanceAsync(tokenAddress, userAddress);
-        if (!proxyAllowance.eq(this._UNLIMITED_ALLOWANCE_IN_BASE_UNITS)) {
-            this._store.setProxyAllowance(tokenAddress, userAddress, proxyAllowance.minus(amountInBaseUnits));
-        }
-    }
-    private async _increaseBalanceAsync(
-        tokenAddress: string,
-        userAddress: string,
-        amountInBaseUnits: BigNumber,
-    ): Promise<void> {
-        const balance = await this._store.getBalanceAsync(tokenAddress, userAddress);
-        this._store.setBalance(tokenAddress, userAddress, balance.plus(amountInBaseUnits));
-    }
-    private async _decreaseBalanceAsync(
-        tokenAddress: string,
-        userAddress: string,
-        amountInBaseUnits: BigNumber,
-    ): Promise<void> {
-        const balance = await this._store.getBalanceAsync(tokenAddress, userAddress);
-        this._store.setBalance(tokenAddress, userAddress, balance.minus(amountInBaseUnits));
-    }
-}
diff --git a/packages/0x.js/src/utils/filter_utils.ts b/packages/0x.js/src/utils/filter_utils.ts
deleted file mode 100644
index c5df7321e..000000000
--- a/packages/0x.js/src/utils/filter_utils.ts
+++ /dev/null
@@ -1,95 +0,0 @@
-import {
-    ConstructorAbi,
-    ContractAbi,
-    EventAbi,
-    FallbackAbi,
-    FilterObject,
-    LogEntry,
-    MethodAbi,
-} from '@0xproject/types';
-import * as ethUtil from 'ethereumjs-util';
-import * as jsSHA3 from 'js-sha3';
-import * as _ from 'lodash';
-import * as uuid from 'uuid/v4';
-
-import { BlockRange, ContractEvents, IndexedFilterValues } from '../types';
-
-const TOPIC_LENGTH = 32;
-
-export const filterUtils = {
-    generateUUID(): string {
-        return uuid();
-    },
-    getFilter(
-        address: string,
-        eventName: ContractEvents,
-        indexFilterValues: IndexedFilterValues,
-        abi: ContractAbi,
-        blockRange?: BlockRange,
-    ): FilterObject {
-        const eventAbi = _.find(abi, { name: eventName }) as EventAbi;
-        const eventSignature = filterUtils.getEventSignatureFromAbiByName(eventAbi, eventName);
-        const topicForEventSignature = ethUtil.addHexPrefix(jsSHA3.keccak256(eventSignature));
-        const topicsForIndexedArgs = filterUtils.getTopicsForIndexedArgs(eventAbi, indexFilterValues);
-        const topics = [topicForEventSignature, ...topicsForIndexedArgs];
-        let filter: FilterObject = {
-            address,
-            topics,
-        };
-        if (!_.isUndefined(blockRange)) {
-            filter = {
-                ...blockRange,
-                ...filter,
-            };
-        }
-        return filter;
-    },
-    getEventSignatureFromAbiByName(eventAbi: EventAbi, eventName: ContractEvents): string {
-        const types = _.map(eventAbi.inputs, 'type');
-        const signature = `${eventAbi.name}(${types.join(',')})`;
-        return signature;
-    },
-    getTopicsForIndexedArgs(abi: EventAbi, indexFilterValues: IndexedFilterValues): Array<string | null> {
-        const topics: Array<string | null> = [];
-        for (const eventInput of abi.inputs) {
-            if (!eventInput.indexed) {
-                continue;
-            }
-            if (_.isUndefined(indexFilterValues[eventInput.name])) {
-                // Null is a wildcard topic in a JSON-RPC call
-                topics.push(null);
-            } else {
-                const value = indexFilterValues[eventInput.name] as string;
-                const buffer = ethUtil.toBuffer(value);
-                const paddedBuffer = ethUtil.setLengthLeft(buffer, TOPIC_LENGTH);
-                const topic = ethUtil.bufferToHex(paddedBuffer);
-                topics.push(topic);
-            }
-        }
-        return topics;
-    },
-    matchesFilter(log: LogEntry, filter: FilterObject): boolean {
-        if (!_.isUndefined(filter.address) && log.address !== filter.address) {
-            return false;
-        }
-        if (!_.isUndefined(filter.topics)) {
-            return filterUtils.matchesTopics(log.topics, filter.topics);
-        }
-        return true;
-    },
-    matchesTopics(logTopics: string[], filterTopics: Array<string[] | string | null>): boolean {
-        const matchesTopic = _.zipWith(logTopics, filterTopics, filterUtils.matchesTopic.bind(filterUtils));
-        const matchesTopics = _.every(matchesTopic);
-        return matchesTopics;
-    },
-    matchesTopic(logTopic: string, filterTopic: string[] | string | null): boolean {
-        if (_.isArray(filterTopic)) {
-            return _.includes(filterTopic, logTopic);
-        }
-        if (_.isString(filterTopic)) {
-            return filterTopic === logTopic;
-        }
-        // null topic is a wildcard
-        return true;
-    },
-};
diff --git a/packages/0x.js/src/utils/order_state_utils.ts b/packages/0x.js/src/utils/order_state_utils.ts
deleted file mode 100644
index b0310d8a8..000000000
--- a/packages/0x.js/src/utils/order_state_utils.ts
+++ /dev/null
@@ -1,138 +0,0 @@
-import { SignedOrder } from '@0xproject/types';
-import { BigNumber } from '@0xproject/utils';
-import * as _ from 'lodash';
-
-import { ZeroEx } from '../0x';
-import { BalanceAndProxyAllowanceFetcher } from '../abstract/balance_and_proxy_allowance_fetcher';
-import { OrderFilledCancelledFetcher } from '../abstract/order_filled_cancelled_fetcher';
-import { ExchangeWrapper } from '../contract_wrappers/exchange_wrapper';
-import { RemainingFillableCalculator } from '../order_watcher/remaining_fillable_calculator';
-import { ExchangeContractErrs, OrderRelevantState, OrderState, OrderStateInvalid, OrderStateValid } from '../types';
-
-const ACCEPTABLE_RELATIVE_ROUNDING_ERROR = 0.0001;
-
-export class OrderStateUtils {
-    private _balanceAndProxyAllowanceFetcher: BalanceAndProxyAllowanceFetcher;
-    private _orderFilledCancelledFetcher: OrderFilledCancelledFetcher;
-    private static _validateIfOrderIsValid(signedOrder: SignedOrder, orderRelevantState: OrderRelevantState): void {
-        const unavailableTakerTokenAmount = orderRelevantState.cancelledTakerTokenAmount.add(
-            orderRelevantState.filledTakerTokenAmount,
-        );
-        const availableTakerTokenAmount = signedOrder.takerTokenAmount.minus(unavailableTakerTokenAmount);
-        if (availableTakerTokenAmount.eq(0)) {
-            throw new Error(ExchangeContractErrs.OrderRemainingFillAmountZero);
-        }
-
-        if (orderRelevantState.makerBalance.eq(0)) {
-            throw new Error(ExchangeContractErrs.InsufficientMakerBalance);
-        }
-        if (orderRelevantState.makerProxyAllowance.eq(0)) {
-            throw new Error(ExchangeContractErrs.InsufficientMakerAllowance);
-        }
-        if (!signedOrder.makerFee.eq(0)) {
-            if (orderRelevantState.makerFeeBalance.eq(0)) {
-                throw new Error(ExchangeContractErrs.InsufficientMakerFeeBalance);
-            }
-            if (orderRelevantState.makerFeeProxyAllowance.eq(0)) {
-                throw new Error(ExchangeContractErrs.InsufficientMakerFeeAllowance);
-            }
-        }
-        const minFillableTakerTokenAmountWithinNoRoundingErrorRange = signedOrder.takerTokenAmount
-            .dividedBy(ACCEPTABLE_RELATIVE_ROUNDING_ERROR)
-            .dividedBy(signedOrder.makerTokenAmount);
-        if (
-            orderRelevantState.remainingFillableTakerTokenAmount.lessThan(
-                minFillableTakerTokenAmountWithinNoRoundingErrorRange,
-            )
-        ) {
-            throw new Error(ExchangeContractErrs.OrderFillRoundingError);
-        }
-    }
-    constructor(
-        balanceAndProxyAllowanceFetcher: BalanceAndProxyAllowanceFetcher,
-        orderFilledCancelledFetcher: OrderFilledCancelledFetcher,
-    ) {
-        this._balanceAndProxyAllowanceFetcher = balanceAndProxyAllowanceFetcher;
-        this._orderFilledCancelledFetcher = orderFilledCancelledFetcher;
-    }
-    public async getOrderStateAsync(signedOrder: SignedOrder): Promise<OrderState> {
-        const orderRelevantState = await this.getOrderRelevantStateAsync(signedOrder);
-        const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-        try {
-            OrderStateUtils._validateIfOrderIsValid(signedOrder, orderRelevantState);
-            const orderState: OrderStateValid = {
-                isValid: true,
-                orderHash,
-                orderRelevantState,
-            };
-            return orderState;
-        } catch (err) {
-            const orderState: OrderStateInvalid = {
-                isValid: false,
-                orderHash,
-                error: err.message,
-            };
-            return orderState;
-        }
-    }
-    public async getOrderRelevantStateAsync(signedOrder: SignedOrder): Promise<OrderRelevantState> {
-        // HACK: We access the private property here but otherwise the interface will be less nice.
-        // If we pass it from the instantiator - there is no opportunity to get it there
-        // because JS doesn't support async constructors.
-        // Moreover - it's cached under the hood so it's equivalent to an async constructor.
-        const exchange = (this._orderFilledCancelledFetcher as any)._exchangeWrapper as ExchangeWrapper;
-        const zrxTokenAddress = exchange.getZRXTokenAddress();
-        const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-        const makerBalance = await this._balanceAndProxyAllowanceFetcher.getBalanceAsync(
-            signedOrder.makerTokenAddress,
-            signedOrder.maker,
-        );
-        const makerProxyAllowance = await this._balanceAndProxyAllowanceFetcher.getProxyAllowanceAsync(
-            signedOrder.makerTokenAddress,
-            signedOrder.maker,
-        );
-        const makerFeeBalance = await this._balanceAndProxyAllowanceFetcher.getBalanceAsync(
-            zrxTokenAddress,
-            signedOrder.maker,
-        );
-        const makerFeeProxyAllowance = await this._balanceAndProxyAllowanceFetcher.getProxyAllowanceAsync(
-            zrxTokenAddress,
-            signedOrder.maker,
-        );
-        const filledTakerTokenAmount = await this._orderFilledCancelledFetcher.getFilledTakerAmountAsync(orderHash);
-        const cancelledTakerTokenAmount = await this._orderFilledCancelledFetcher.getCancelledTakerAmountAsync(
-            orderHash,
-        );
-        const unavailableTakerTokenAmount = await exchange.getUnavailableTakerAmountAsync(orderHash);
-        const totalMakerTokenAmount = signedOrder.makerTokenAmount;
-        const totalTakerTokenAmount = signedOrder.takerTokenAmount;
-        const remainingTakerTokenAmount = totalTakerTokenAmount.minus(unavailableTakerTokenAmount);
-        const remainingMakerTokenAmount = remainingTakerTokenAmount
-            .times(totalMakerTokenAmount)
-            .dividedToIntegerBy(totalTakerTokenAmount);
-        const transferrableMakerTokenAmount = BigNumber.min([makerProxyAllowance, makerBalance]);
-        const transferrableFeeTokenAmount = BigNumber.min([makerFeeProxyAllowance, makerFeeBalance]);
-
-        const isMakerTokenZRX = signedOrder.makerTokenAddress === zrxTokenAddress;
-        const remainingFillableCalculator = new RemainingFillableCalculator(
-            signedOrder,
-            isMakerTokenZRX,
-            transferrableMakerTokenAmount,
-            transferrableFeeTokenAmount,
-            remainingMakerTokenAmount,
-        );
-        const remainingFillableMakerTokenAmount = remainingFillableCalculator.computeRemainingMakerFillable();
-        const remainingFillableTakerTokenAmount = remainingFillableCalculator.computeRemainingTakerFillable();
-        const orderRelevantState = {
-            makerBalance,
-            makerProxyAllowance,
-            makerFeeBalance,
-            makerFeeProxyAllowance,
-            filledTakerTokenAmount,
-            cancelledTakerTokenAmount,
-            remainingFillableMakerTokenAmount,
-            remainingFillableTakerTokenAmount,
-        };
-        return orderRelevantState;
-    }
-}
diff --git a/packages/0x.js/src/utils/order_validation_utils.ts b/packages/0x.js/src/utils/order_validation_utils.ts
deleted file mode 100644
index a13c3dc04..000000000
--- a/packages/0x.js/src/utils/order_validation_utils.ts
+++ /dev/null
@@ -1,199 +0,0 @@
-import { getOrderHashHex, OrderError } from '@0xproject/order-utils';
-import { Order, SignedOrder } from '@0xproject/types';
-import { BigNumber } from '@0xproject/utils';
-import * as _ from 'lodash';
-
-import { ZeroEx } from '../0x';
-import { ExchangeWrapper } from '../contract_wrappers/exchange_wrapper';
-import { ExchangeContractErrs, TradeSide, TransferType, ZeroExError } from '../types';
-import { constants } from '../utils/constants';
-import { utils } from '../utils/utils';
-
-import { ExchangeTransferSimulator } from './exchange_transfer_simulator';
-
-export class OrderValidationUtils {
-    private _exchangeWrapper: ExchangeWrapper;
-    public static validateCancelOrderThrowIfInvalid(
-        order: Order,
-        cancelTakerTokenAmount: BigNumber,
-        unavailableTakerTokenAmount: BigNumber,
-    ): void {
-        if (cancelTakerTokenAmount.eq(0)) {
-            throw new Error(ExchangeContractErrs.OrderCancelAmountZero);
-        }
-        if (order.takerTokenAmount.eq(unavailableTakerTokenAmount)) {
-            throw new Error(ExchangeContractErrs.OrderAlreadyCancelledOrFilled);
-        }
-        const currentUnixTimestampSec = utils.getCurrentUnixTimestampSec();
-        if (order.expirationUnixTimestampSec.lessThan(currentUnixTimestampSec)) {
-            throw new Error(ExchangeContractErrs.OrderCancelExpired);
-        }
-    }
-    public static async validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
-        exchangeTradeEmulator: ExchangeTransferSimulator,
-        signedOrder: SignedOrder,
-        fillTakerTokenAmount: BigNumber,
-        senderAddress: string,
-        zrxTokenAddress: string,
-    ): Promise<void> {
-        const fillMakerTokenAmount = OrderValidationUtils._getPartialAmount(
-            fillTakerTokenAmount,
-            signedOrder.takerTokenAmount,
-            signedOrder.makerTokenAmount,
-        );
-        await exchangeTradeEmulator.transferFromAsync(
-            signedOrder.makerTokenAddress,
-            signedOrder.maker,
-            senderAddress,
-            fillMakerTokenAmount,
-            TradeSide.Maker,
-            TransferType.Trade,
-        );
-        await exchangeTradeEmulator.transferFromAsync(
-            signedOrder.takerTokenAddress,
-            senderAddress,
-            signedOrder.maker,
-            fillTakerTokenAmount,
-            TradeSide.Taker,
-            TransferType.Trade,
-        );
-        const makerFeeAmount = OrderValidationUtils._getPartialAmount(
-            fillTakerTokenAmount,
-            signedOrder.takerTokenAmount,
-            signedOrder.makerFee,
-        );
-        await exchangeTradeEmulator.transferFromAsync(
-            zrxTokenAddress,
-            signedOrder.maker,
-            signedOrder.feeRecipient,
-            makerFeeAmount,
-            TradeSide.Maker,
-            TransferType.Fee,
-        );
-        const takerFeeAmount = OrderValidationUtils._getPartialAmount(
-            fillTakerTokenAmount,
-            signedOrder.takerTokenAmount,
-            signedOrder.takerFee,
-        );
-        await exchangeTradeEmulator.transferFromAsync(
-            zrxTokenAddress,
-            senderAddress,
-            signedOrder.feeRecipient,
-            takerFeeAmount,
-            TradeSide.Taker,
-            TransferType.Fee,
-        );
-    }
-    private static _validateRemainingFillAmountNotZeroOrThrow(
-        takerTokenAmount: BigNumber,
-        unavailableTakerTokenAmount: BigNumber,
-    ) {
-        if (takerTokenAmount.eq(unavailableTakerTokenAmount)) {
-            throw new Error(ExchangeContractErrs.OrderRemainingFillAmountZero);
-        }
-    }
-    private static _validateOrderNotExpiredOrThrow(expirationUnixTimestampSec: BigNumber) {
-        const currentUnixTimestampSec = utils.getCurrentUnixTimestampSec();
-        if (expirationUnixTimestampSec.lessThan(currentUnixTimestampSec)) {
-            throw new Error(ExchangeContractErrs.OrderFillExpired);
-        }
-    }
-    private static _getPartialAmount(numerator: BigNumber, denominator: BigNumber, target: BigNumber): BigNumber {
-        const fillMakerTokenAmount = numerator
-            .mul(target)
-            .div(denominator)
-            .round(0);
-        return fillMakerTokenAmount;
-    }
-    constructor(exchangeWrapper: ExchangeWrapper) {
-        this._exchangeWrapper = exchangeWrapper;
-    }
-    public async validateOrderFillableOrThrowAsync(
-        exchangeTradeEmulator: ExchangeTransferSimulator,
-        signedOrder: SignedOrder,
-        zrxTokenAddress: string,
-        expectedFillTakerTokenAmount?: BigNumber,
-    ): Promise<void> {
-        const orderHash = getOrderHashHex(signedOrder);
-        const unavailableTakerTokenAmount = await this._exchangeWrapper.getUnavailableTakerAmountAsync(orderHash);
-        OrderValidationUtils._validateRemainingFillAmountNotZeroOrThrow(
-            signedOrder.takerTokenAmount,
-            unavailableTakerTokenAmount,
-        );
-        OrderValidationUtils._validateOrderNotExpiredOrThrow(signedOrder.expirationUnixTimestampSec);
-        let fillTakerTokenAmount = signedOrder.takerTokenAmount.minus(unavailableTakerTokenAmount);
-        if (!_.isUndefined(expectedFillTakerTokenAmount)) {
-            fillTakerTokenAmount = expectedFillTakerTokenAmount;
-        }
-        await OrderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
-            exchangeTradeEmulator,
-            signedOrder,
-            fillTakerTokenAmount,
-            signedOrder.taker,
-            zrxTokenAddress,
-        );
-    }
-    public async validateFillOrderThrowIfInvalidAsync(
-        exchangeTradeEmulator: ExchangeTransferSimulator,
-        signedOrder: SignedOrder,
-        fillTakerTokenAmount: BigNumber,
-        takerAddress: string,
-        zrxTokenAddress: string,
-    ): Promise<BigNumber> {
-        if (fillTakerTokenAmount.eq(0)) {
-            throw new Error(ExchangeContractErrs.OrderFillAmountZero);
-        }
-        const orderHash = getOrderHashHex(signedOrder);
-        if (!ZeroEx.isValidSignature(orderHash, signedOrder.ecSignature, signedOrder.maker)) {
-            throw new Error(OrderError.InvalidSignature);
-        }
-        const unavailableTakerTokenAmount = await this._exchangeWrapper.getUnavailableTakerAmountAsync(orderHash);
-        OrderValidationUtils._validateRemainingFillAmountNotZeroOrThrow(
-            signedOrder.takerTokenAmount,
-            unavailableTakerTokenAmount,
-        );
-        if (signedOrder.taker !== constants.NULL_ADDRESS && signedOrder.taker !== takerAddress) {
-            throw new Error(ExchangeContractErrs.TransactionSenderIsNotFillOrderTaker);
-        }
-        OrderValidationUtils._validateOrderNotExpiredOrThrow(signedOrder.expirationUnixTimestampSec);
-        const remainingTakerTokenAmount = signedOrder.takerTokenAmount.minus(unavailableTakerTokenAmount);
-        const filledTakerTokenAmount = remainingTakerTokenAmount.lessThan(fillTakerTokenAmount)
-            ? remainingTakerTokenAmount
-            : fillTakerTokenAmount;
-        await OrderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
-            exchangeTradeEmulator,
-            signedOrder,
-            filledTakerTokenAmount,
-            takerAddress,
-            zrxTokenAddress,
-        );
-
-        const wouldRoundingErrorOccur = await this._exchangeWrapper.isRoundingErrorAsync(
-            filledTakerTokenAmount,
-            signedOrder.takerTokenAmount,
-            signedOrder.makerTokenAmount,
-        );
-        if (wouldRoundingErrorOccur) {
-            throw new Error(ExchangeContractErrs.OrderFillRoundingError);
-        }
-        return filledTakerTokenAmount;
-    }
-    public async validateFillOrKillOrderThrowIfInvalidAsync(
-        exchangeTradeEmulator: ExchangeTransferSimulator,
-        signedOrder: SignedOrder,
-        fillTakerTokenAmount: BigNumber,
-        takerAddress: string,
-        zrxTokenAddress: string,
-    ): Promise<void> {
-        const filledTakerTokenAmount = await this.validateFillOrderThrowIfInvalidAsync(
-            exchangeTradeEmulator,
-            signedOrder,
-            fillTakerTokenAmount,
-            takerAddress,
-            zrxTokenAddress,
-        );
-        if (filledTakerTokenAmount !== fillTakerTokenAmount) {
-            throw new Error(ExchangeContractErrs.InsufficientRemainingFillAmount);
-        }
-    }
-}
diff --git a/packages/0x.js/src/utils/utils.ts b/packages/0x.js/src/utils/utils.ts
deleted file mode 100644
index af1125632..000000000
--- a/packages/0x.js/src/utils/utils.ts
+++ /dev/null
@@ -1,13 +0,0 @@
-import { BigNumber } from '@0xproject/utils';
-
-export const utils = {
-    spawnSwitchErr(name: string, value: any): Error {
-        return new Error(`Unexpected switch value: ${value} encountered for ${name}`);
-    },
-    getCurrentUnixTimestampSec(): BigNumber {
-        return new BigNumber(Date.now() / 1000).round();
-    },
-    getCurrentUnixTimestampMs(): BigNumber {
-        return new BigNumber(Date.now());
-    },
-};