Merge pull request #151 from 0xProject/feature/remove-truffle-contracts

Remove truffle contracts dependency

14 files changed, 469 insertions, 281 deletions

diff --git a/src/0x.ts b/src/0x.ts
index ba222f2c9..0af164b1e 100644
--- a/src/0x.ts
+++ b/src/0x.ts
@@ -1,9 +1,10 @@
 import * as _ from 'lodash';
 import * as BigNumber from 'bignumber.js';
+import * as Web3 from 'web3';
+import * as abiDecoder from 'abi-decoder';
 import {SchemaValidator, schemas} from '0x-json-schemas';
 import {bigNumberConfigs} from './bignumber_config';
 import * as ethUtil from 'ethereumjs-util';
-import contract = require('truffle-contract');
 import findVersions = require('find-versions');
 import compareVersions = require('compare-versions');
 import {Web3Wrapper} from './web3_wrapper';
@@ -11,12 +12,24 @@ import {constants} from './utils/constants';
 import {utils} from './utils/utils';
 import {signatureUtils} from './utils/signature_utils';
 import {assert} from './utils/assert';
+import {artifacts} from './artifacts';
 import {ExchangeWrapper} from './contract_wrappers/exchange_wrapper';
 import {TokenRegistryWrapper} from './contract_wrappers/token_registry_wrapper';
 import {EtherTokenWrapper} from './contract_wrappers/ether_token_wrapper';
 import {TokenWrapper} from './contract_wrappers/token_wrapper';
 import {TokenTransferProxyWrapper} from './contract_wrappers/token_transfer_proxy_wrapper';
-import {ECSignature, ZeroExError, Order, SignedOrder, Web3Provider, ZeroExConfig} from './types';
+import {
+    ECSignature,
+    ZeroExError,
+    Order,
+    SignedOrder,
+    Web3Provider,
+    ZeroExConfig,
+    TransactionReceipt,
+    DecodedLogArgs,
+    TransactionReceiptWithDecodedLogs,
+    LogWithDecodedArgs,
+} from './types';
 
 // Customize our BigNumber instances
 bigNumberConfigs.configure();
@@ -170,13 +183,17 @@ export class ZeroEx {
             // We re-assign the send method so that Web3@1.0 providers work with 0x.js
             (provider as any).sendAsync = (provider as any).send;
         }
-        this._web3Wrapper = new Web3Wrapper(provider);
+        this._registerArtifactsWithinABIDecoder();
         const gasPrice = _.isUndefined(config) ? undefined : config.gasPrice;
-        this.token = new TokenWrapper(this._web3Wrapper, gasPrice);
-        this.proxy = new TokenTransferProxyWrapper(this._web3Wrapper, gasPrice);
-        this.exchange = new ExchangeWrapper(this._web3Wrapper, this.token, gasPrice);
-        this.tokenRegistry = new TokenRegistryWrapper(this._web3Wrapper, gasPrice);
-        this.etherToken = new EtherTokenWrapper(this._web3Wrapper, this.token, gasPrice);
+        const defaults = {
+            gasPrice,
+        };
+        this._web3Wrapper = new Web3Wrapper(provider, defaults);
+        this.token = new TokenWrapper(this._web3Wrapper);
+        this.proxy = new TokenTransferProxyWrapper(this._web3Wrapper);
+        this.exchange = new ExchangeWrapper(this._web3Wrapper, this.token);
+        this.tokenRegistry = new TokenRegistryWrapper(this._web3Wrapper);
+        this.etherToken = new EtherTokenWrapper(this._web3Wrapper, this.token);
     }
     /**
      * Sets a new web3 provider for 0x.js. Updating the provider will stop all
@@ -249,4 +266,47 @@ export class ZeroEx {
 
         throw new Error(ZeroExError.InvalidSignature);
     }
+    /**
+     * Waits for a transaction to be mined and returns the transaction receipt.
+     * @param   txHash            Transaction hash
+     * @param   pollingIntervalMs How often (in ms) should we check if the transaction is mined.
+     * @return  Transaction receipt with decoded log args.
+     */
+    public async awaitTransactionMinedAsync(
+        txHash: string, pollingIntervalMs: number = 1000): Promise<TransactionReceiptWithDecodedLogs> {
+        const txReceiptPromise = new Promise(
+            (resolve: (receipt: TransactionReceiptWithDecodedLogs) => void, reject) => {
+            const intervalId = setInterval(async () => {
+                const transactionReceipt = await this._web3Wrapper.getTransactionReceiptAsync(txHash);
+                if (!_.isNull(transactionReceipt)) {
+                    clearInterval(intervalId);
+                    const logsWithDecodedArgs = _.map(transactionReceipt.logs, (log: Web3.LogEntry) => {
+                        const decodedLog = abiDecoder.decodeLogs([log])[0];
+                        const decodedArgs = decodedLog.events;
+                        const args: DecodedLogArgs = {};
+                        _.forEach(decodedArgs, arg => {
+                            args[arg.name] = arg.value;
+                        });
+                        const logWithDecodedArgs: LogWithDecodedArgs = {
+                            ...log,
+                            args,
+                            event: decodedLog.name,
+                        };
+                        return logWithDecodedArgs;
+                    });
+                    const transactionReceiptWithDecodedLogArgs: TransactionReceiptWithDecodedLogs = {
+                        ...transactionReceipt,
+                        logs: logsWithDecodedArgs,
+                    };
+                    resolve(transactionReceiptWithDecodedLogArgs);
+                }
+            }, pollingIntervalMs);
+        });
+        return txReceiptPromise;
+    }
+    private _registerArtifactsWithinABIDecoder(): void {
+        for (const artifact of _.values(artifacts)) {
+            abiDecoder.addABI(artifact.abi);
+        }
+    }
 }
diff --git a/src/artifacts.ts b/src/artifacts.ts
new file mode 100644
index 000000000..0c4627337
--- /dev/null
+++ b/src/artifacts.ts
@@ -0,0 +1,13 @@
+import * as TokenArtifact from './artifacts/Token.json';
+import * as ExchangeArtifact from './artifacts/Exchange.json';
+import * as EtherTokenArtifact from './artifacts/EtherToken.json';
+import * as TokenRegistryArtifact from './artifacts/TokenRegistry.json';
+import * as TokenTransferProxyArtifact from './artifacts/TokenTransferProxy.json';
+
+export const artifacts = {
+    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/src/artifacts/EtherToken.json b/src/artifacts/EtherToken.json
index eca348530..54b5a032e 100644
--- a/src/artifacts/EtherToken.json
+++ b/src/artifacts/EtherToken.json
@@ -391,4 +391,4 @@
   },
   "schema_version": "0.0.5",
   "updated_at": 1503318938233
-}
\ No newline at end of file
+}
diff --git a/src/contract.ts b/src/contract.ts
new file mode 100644
index 000000000..1aacc65dc
--- /dev/null
+++ b/src/contract.ts
@@ -0,0 +1,80 @@
+import * as Web3 from 'web3';
+import * as _ from 'lodash';
+import promisify = require('es6-promisify');
+import {SchemaValidator, schemas} from '0x-json-schemas';
+import {AbiType} from './types';
+
+export class Contract implements Web3.ContractInstance {
+    public address: string;
+    public abi: Web3.ContractAbi;
+    private contract: Web3.ContractInstance;
+    private defaults: Partial<Web3.TxData>;
+    private validator: SchemaValidator;
+    // This class instance is going to be populated with functions and events depending on the ABI
+    // and we don't know their types in advance
+    [name: string]: any;
+    constructor(web3ContractInstance: Web3.ContractInstance, defaults: Partial<Web3.TxData>) {
+        this.contract = web3ContractInstance;
+        this.address = web3ContractInstance.address;
+        this.abi = web3ContractInstance.abi;
+        this.defaults = defaults;
+        this.populateEvents();
+        this.populateFunctions();
+        this.validator = new SchemaValidator();
+    }
+    private populateFunctions(): void {
+        const functionsAbi = _.filter(this.abi, abiPart => abiPart.type === AbiType.Function);
+        _.forEach(functionsAbi, (functionAbi: Web3.MethodAbi) => {
+            if (functionAbi.constant) {
+                const cbStyleCallFunction = this.contract[functionAbi.name].call;
+                this[functionAbi.name] = {
+                    callAsync: promisify(cbStyleCallFunction, this.contract),
+                };
+            } else {
+                const cbStyleFunction = this.contract[functionAbi.name];
+                const cbStyleEstimateGasFunction = this.contract[functionAbi.name].estimateGas;
+                this[functionAbi.name] = {
+                    estimateGasAsync: promisify(cbStyleEstimateGasFunction, this.contract),
+                    sendTransactionAsync: this.promisifyWithDefaultParams(cbStyleFunction),
+                };
+            }
+        });
+    }
+    private populateEvents(): void {
+        const eventsAbi = _.filter(this.abi, abiPart => abiPart.type === AbiType.Event);
+        _.forEach(eventsAbi, (eventAbi: Web3.EventAbi) => {
+            this[eventAbi.name] = this.contract[eventAbi.name];
+        });
+    }
+    private promisifyWithDefaultParams(fn: (...args: any[]) => void): (...args: any[]) => Promise<any> {
+        const promisifiedWithDefaultParams = (...args: any[]) => {
+            const promise = new Promise((resolve, reject) => {
+                const lastArg = args[args.length - 1];
+                let txData: Partial<Web3.TxData> = {};
+                if (this.isTxData(lastArg)) {
+                    txData = args.pop();
+                }
+                txData = {
+                    ...this.defaults,
+                    ...txData,
+                };
+                const callback = (err: Error, data: any) => {
+                    if (_.isNull(err)) {
+                        resolve(data);
+                    } else {
+                        reject(err);
+                    }
+                };
+                args.push(txData);
+                args.push(callback);
+                fn.apply(this.contract, args);
+            });
+            return promise;
+        };
+        return promisifiedWithDefaultParams;
+    }
+    private isTxData(lastArg: any): boolean {
+        const isValid = this.validator.isValid(lastArg, schemas.txDataSchema);
+        return isValid;
+    }
+}
diff --git a/src/contract_wrappers/contract_wrapper.ts b/src/contract_wrappers/contract_wrapper.ts
index 28df82cee..ca19342f3 100644
--- a/src/contract_wrappers/contract_wrapper.ts
+++ b/src/contract_wrappers/contract_wrapper.ts
@@ -1,53 +1,18 @@
 import * as _ from 'lodash';
-import contract = require('truffle-contract');
+import * as Web3 from 'web3';
 import {Web3Wrapper} from '../web3_wrapper';
-import {ZeroExError, Artifact, ContractInstance} from '../types';
+import {ZeroExError} from '../types';
 import {utils} from '../utils/utils';
 
 export class ContractWrapper {
     protected _web3Wrapper: Web3Wrapper;
-    private _gasPrice?: BigNumber.BigNumber;
-    constructor(web3Wrapper: Web3Wrapper, gasPrice?: BigNumber.BigNumber) {
+    constructor(web3Wrapper: Web3Wrapper) {
         this._web3Wrapper = web3Wrapper;
-        this._gasPrice = gasPrice;
     }
-    protected async _instantiateContractIfExistsAsync(artifact: Artifact, address?: string): Promise<ContractInstance> {
-        const c = await contract(artifact);
-        c.defaults({
-            gasPrice: this._gasPrice,
-        });
-        const providerObj = this._web3Wrapper.getCurrentProvider();
-        c.setProvider(providerObj);
-
-        const networkIdIfExists = await this._web3Wrapper.getNetworkIdIfExistsAsync();
-        const artifactNetworkConfigs = _.isUndefined(networkIdIfExists) ?
-                                       undefined :
-                                       artifact.networks[networkIdIfExists];
-        let contractAddress;
-        if (!_.isUndefined(address)) {
-            contractAddress = address;
-        } else if (!_.isUndefined(artifactNetworkConfigs)) {
-            contractAddress = artifactNetworkConfigs.address.toLowerCase();
-        }
-
-        if (!_.isUndefined(contractAddress)) {
-            const doesContractExist = await this._web3Wrapper.doesContractExistAtAddressAsync(contractAddress);
-            if (!doesContractExist) {
-                throw new Error(ZeroExError.ContractDoesNotExist);
-            }
-        }
-
-        try {
-            const contractInstance = _.isUndefined(address) ? await c.deployed() : await c.at(address);
-            return contractInstance;
-        } catch (err) {
-            const errMsg = `${err}`;
-            if (_.includes(errMsg, 'not been deployed to detected network')) {
-                throw new Error(ZeroExError.ContractDoesNotExist);
-            } else {
-                utils.consoleLog(`Notice: Error encountered: ${err} ${err.stack}`);
-                throw new Error(ZeroExError.UnhandledError);
-            }
-        }
+    protected async _instantiateContractIfExistsAsync<A extends Web3.ContractInstance>(artifact: Artifact,
+                                                                                       address?: string): Promise<A> {
+        const contractInstance =
+            await this._web3Wrapper.getContractInstanceFromArtifactAsync<A>(artifact, address);
+        return contractInstance;
     }
 }
diff --git a/src/contract_wrappers/ether_token_wrapper.ts b/src/contract_wrappers/ether_token_wrapper.ts
index 3c282510f..b86309f90 100644
--- a/src/contract_wrappers/ether_token_wrapper.ts
+++ b/src/contract_wrappers/ether_token_wrapper.ts
@@ -4,7 +4,7 @@ import {ContractWrapper} from './contract_wrapper';
 import {TokenWrapper} from './token_wrapper';
 import {EtherTokenContract, ZeroExError} from '../types';
 import {assert} from '../utils/assert';
-import * as EtherTokenArtifacts from '../artifacts/EtherToken.json';
+import {artifacts} from '../artifacts';
 
 /**
  * This class includes all the functionality related to interacting with a wrapped Ether ERC20 token contract.
@@ -13,8 +13,8 @@ import * as EtherTokenArtifacts from '../artifacts/EtherToken.json';
 export class EtherTokenWrapper extends ContractWrapper {
     private _etherTokenContractIfExists?: EtherTokenContract;
     private _tokenWrapper: TokenWrapper;
-    constructor(web3Wrapper: Web3Wrapper, tokenWrapper: TokenWrapper, gasPrice?: BigNumber.BigNumber) {
-        super(web3Wrapper, gasPrice);
+    constructor(web3Wrapper: Web3Wrapper, tokenWrapper: TokenWrapper) {
+        super(web3Wrapper);
         this._tokenWrapper = tokenWrapper;
     }
     /**
@@ -23,8 +23,9 @@ export class EtherTokenWrapper extends ContractWrapper {
      * for ETH.
      * @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.
+     * @return Transaction hash.
      */
-    public async depositAsync(amountInWei: BigNumber.BigNumber, depositor: string): Promise<void> {
+    public async depositAsync(amountInWei: BigNumber.BigNumber, depositor: string): Promise<string> {
         assert.isBigNumber('amountInWei', amountInWei);
         await assert.isSenderAddressAsync('depositor', depositor, this._web3Wrapper);
 
@@ -32,18 +33,20 @@ export class EtherTokenWrapper extends ContractWrapper {
         assert.assert(ethBalanceInWei.gte(amountInWei), ZeroExError.InsufficientEthBalanceForDeposit);
 
         const wethContract = await this._getEtherTokenContractAsync();
-        await wethContract.deposit({
+        const txHash = await wethContract.deposit.sendTransactionAsync({
             from: depositor,
             value: amountInWei,
         });
+        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   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 withdrawl.
+     * @return Transaction hash.
      */
-    public async withdrawAsync(amountInWei: BigNumber.BigNumber, withdrawer: string): Promise<void> {
+    public async withdrawAsync(amountInWei: BigNumber.BigNumber, withdrawer: string): Promise<string> {
         assert.isBigNumber('amountInWei', amountInWei);
         await assert.isSenderAddressAsync('withdrawer', withdrawer, this._web3Wrapper);
 
@@ -52,9 +55,10 @@ export class EtherTokenWrapper extends ContractWrapper {
         assert.assert(WETHBalanceInBaseUnits.gte(amountInWei), ZeroExError.InsufficientWEthBalanceForWithdrawal);
 
         const wethContract = await this._getEtherTokenContractAsync();
-        await wethContract.withdraw(amountInWei, {
+        const txHash = await wethContract.withdraw.sendTransactionAsync(amountInWei, {
             from: withdrawer,
         });
+        return txHash;
     }
     /**
      * Retrieves the Wrapped Ether token contract address
@@ -71,7 +75,9 @@ export class EtherTokenWrapper extends ContractWrapper {
         if (!_.isUndefined(this._etherTokenContractIfExists)) {
             return this._etherTokenContractIfExists;
         }
-        const contractInstance = await this._instantiateContractIfExistsAsync((EtherTokenArtifacts as any));
+        const contractInstance = await this._instantiateContractIfExistsAsync<EtherTokenContract>(
+            artifacts.EtherTokenArtifact,
+        );
         this._etherTokenContractIfExists = contractInstance as EtherTokenContract;
         return this._etherTokenContractIfExists;
     }
diff --git a/src/contract_wrappers/exchange_wrapper.ts b/src/contract_wrappers/exchange_wrapper.ts
index d09df236b..115bd1110 100644
--- a/src/contract_wrappers/exchange_wrapper.ts
+++ b/src/contract_wrappers/exchange_wrapper.ts
@@ -21,7 +21,6 @@ import {
     IndexedFilterValues,
     CreateContractEvent,
     ContractEventObj,
-    ContractResponse,
     OrderCancellationRequest,
     OrderFillRequest,
     LogErrorContractEventArgs,
@@ -36,21 +35,13 @@ import {ContractWrapper} from './contract_wrapper';
 import {constants} from '../utils/constants';
 import {TokenWrapper} from './token_wrapper';
 import {decorators} from '../utils/decorators';
-import * as ExchangeArtifacts from '../artifacts/Exchange.json';
+import {artifacts} from '../artifacts';
 
 /**
  * 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 _exchangeContractErrCodesToMsg = {
-        [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 _exchangeContractIfExists?: ExchangeContract;
     private _exchangeLogEventEmitters: ContractEventEmitter[];
     private _orderValidationUtils: OrderValidationUtils;
@@ -73,8 +64,8 @@ export class ExchangeWrapper extends ContractWrapper {
         ];
         return [orderAddresses, orderValues];
     }
-    constructor(web3Wrapper: Web3Wrapper, tokenWrapper: TokenWrapper, gasPrice?: BigNumber.BigNumber) {
-        super(web3Wrapper, gasPrice);
+    constructor(web3Wrapper: Web3Wrapper, tokenWrapper: TokenWrapper) {
+        super(web3Wrapper);
         this._tokenWrapper = tokenWrapper;
         this._orderValidationUtils = new OrderValidationUtils(tokenWrapper, this);
         this._exchangeLogEventEmitters = [];
@@ -91,7 +82,7 @@ export class ExchangeWrapper extends ContractWrapper {
         assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
 
         const exchangeContract = await this._getExchangeContractAsync();
-        let unavailableTakerTokenAmount = await exchangeContract.getUnavailableTakerTokenAmount.call(orderHash);
+        let unavailableTakerTokenAmount = await exchangeContract.getUnavailableTakerTokenAmount.callAsync(orderHash);
         // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
         unavailableTakerTokenAmount = new BigNumber(unavailableTakerTokenAmount);
         return unavailableTakerTokenAmount;
@@ -105,7 +96,7 @@ export class ExchangeWrapper extends ContractWrapper {
         assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
 
         const exchangeContract = await this._getExchangeContractAsync();
-        let fillAmountInBaseUnits = await exchangeContract.filled.call(orderHash);
+        let fillAmountInBaseUnits = await exchangeContract.filled.callAsync(orderHash);
         // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
         fillAmountInBaseUnits = new BigNumber(fillAmountInBaseUnits);
         return fillAmountInBaseUnits;
@@ -120,7 +111,7 @@ export class ExchangeWrapper extends ContractWrapper {
         assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
 
         const exchangeContract = await this._getExchangeContractAsync();
-        let cancelledAmountInBaseUnits = await exchangeContract.cancelled.call(orderHash);
+        let cancelledAmountInBaseUnits = await exchangeContract.cancelled.callAsync(orderHash);
         // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
         cancelledAmountInBaseUnits = new BigNumber(cancelledAmountInBaseUnits);
         return cancelledAmountInBaseUnits;
@@ -141,12 +132,12 @@ export class ExchangeWrapper extends ContractWrapper {
      * @param   takerAddress                                The user Ethereum address who would like to fill this order.
      *                                                      Must be available via the supplied Web3.Provider
      *                                                      passed to 0x.js.
-     * @return The amount of the order that was filled (in taker token baseUnits).
+     * @return Transaction hash.
      */
     @decorators.contractCallErrorHandler
     public async fillOrderAsync(signedOrder: SignedOrder, fillTakerTokenAmount: BigNumber.BigNumber,
                                 shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-                                takerAddress: string): Promise<BigNumber.BigNumber> {
+                                takerAddress: string): Promise<string> {
         assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
         assert.isBigNumber('fillTakerTokenAmount', fillTakerTokenAmount);
         assert.isBoolean('shouldThrowOnInsufficientBalanceOrAllowance', shouldThrowOnInsufficientBalanceOrAllowance);
@@ -157,7 +148,7 @@ export class ExchangeWrapper extends ContractWrapper {
 
         const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(signedOrder);
 
-        const gas = await exchangeInstance.fillOrder.estimateGas(
+        const gas = await exchangeInstance.fillOrder.estimateGasAsync(
             orderAddresses,
             orderValues,
             fillTakerTokenAmount,
@@ -169,7 +160,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 from: takerAddress,
             },
         );
-        const response: ContractResponse = await exchangeInstance.fillOrder(
+        const txHash: string = await exchangeInstance.fillOrder.sendTransactionAsync(
             orderAddresses,
             orderValues,
             fillTakerTokenAmount,
@@ -182,10 +173,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 gas,
             },
         );
-        this._throwErrorLogsAsErrors(response.logs);
-        const logFillArgs = response.logs[0].args as LogFillContractEventArgs;
-        const filledTakerTokenAmount = new BigNumber(logFillArgs.filledTakerTokenAmount);
-        return filledTakerTokenAmount;
+        return txHash;
     }
     /**
      * Sequentially and atomically fills signedOrders up to the specified takerTokenFillAmount.
@@ -201,12 +189,12 @@ export class ExchangeWrapper extends ContractWrapper {
      * @param   takerAddress                                The user Ethereum address who would like to fill these
      *                                                      orders. Must be available via the supplied Web3.Provider
      *                                                      passed to 0x.js.
-     * @return The amount of the orders that was filled (in taker token baseUnits).
+     * @return Transaction hash.
      */
     @decorators.contractCallErrorHandler
     public async fillOrdersUpToAsync(signedOrders: SignedOrder[], fillTakerTokenAmount: BigNumber.BigNumber,
                                      shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-                                     takerAddress: string): Promise<BigNumber.BigNumber> {
+                                     takerAddress: string): Promise<string> {
         assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
         const takerTokenAddresses = _.map(signedOrders, signedOrder => signedOrder.takerTokenAddress);
         assert.hasAtMostOneUniqueValue(takerTokenAddresses,
@@ -222,7 +210,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 signedOrder, fillTakerTokenAmount, takerAddress);
         }
         if (_.isEmpty(signedOrders)) {
-            return new BigNumber(0); // no-op
+            throw new Error(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
         }
 
         const orderAddressesValuesAndSignatureArray = _.map(signedOrders, signedOrder => {
@@ -239,7 +227,7 @@ export class ExchangeWrapper extends ContractWrapper {
         );
 
         const exchangeInstance = await this._getExchangeContractAsync();
-        const gas = await exchangeInstance.fillOrdersUpTo.estimateGas(
+        const gas = await exchangeInstance.fillOrdersUpTo.estimateGasAsync(
             orderAddressesArray,
             orderValuesArray,
             fillTakerTokenAmount,
@@ -251,7 +239,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 from: takerAddress,
             },
         );
-        const response: ContractResponse = await exchangeInstance.fillOrdersUpTo(
+        const txHash = await exchangeInstance.fillOrdersUpTo.sendTransactionAsync(
             orderAddressesArray,
             orderValuesArray,
             fillTakerTokenAmount,
@@ -264,13 +252,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 gas,
             },
         );
-        this._throwErrorLogsAsErrors(response.logs);
-        let filledTakerTokenAmount = new BigNumber(0);
-        _.each(response.logs, log => {
-            filledTakerTokenAmount = filledTakerTokenAmount.plus(
-                (log.args as LogFillContractEventArgs).filledTakerTokenAmount);
-        });
-        return filledTakerTokenAmount;
+        return txHash;
     }
     /**
      * Batch version of fillOrderAsync.
@@ -288,11 +270,12 @@ export class ExchangeWrapper extends ContractWrapper {
      * @param   takerAddress                                    The user Ethereum address who would like to fill
      *                                                          these orders. Must be available via the supplied
      *                                                          Web3.Provider passed to 0x.js.
+     * @return Transaction hash.
      */
     @decorators.contractCallErrorHandler
     public async batchFillOrdersAsync(orderFillRequests: OrderFillRequest[],
                                       shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-                                      takerAddress: string): Promise<void> {
+                                      takerAddress: string): Promise<string> {
         assert.doesConformToSchema('orderFillRequests', orderFillRequests, schemas.orderFillRequestsSchema);
         const exchangeContractAddresses = _.map(
             orderFillRequests,
@@ -307,7 +290,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 orderFillRequest.signedOrder, orderFillRequest.takerTokenFillAmount, takerAddress);
         }
         if (_.isEmpty(orderFillRequests)) {
-            return; // no-op
+            throw new Error(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
         }
 
         const orderAddressesValuesAmountsAndSignatureArray = _.map(orderFillRequests, orderFillRequest => {
@@ -325,7 +308,7 @@ export class ExchangeWrapper extends ContractWrapper {
         );
 
         const exchangeInstance = await this._getExchangeContractAsync();
-        const gas = await exchangeInstance.batchFillOrders.estimateGas(
+        const gas = await exchangeInstance.batchFillOrders.estimateGasAsync(
             orderAddressesArray,
             orderValuesArray,
             fillTakerTokenAmounts,
@@ -337,7 +320,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 from: takerAddress,
             },
         );
-        const response: ContractResponse = await exchangeInstance.batchFillOrders(
+        const txHash = await exchangeInstance.batchFillOrders.sendTransactionAsync(
             orderAddressesArray,
             orderValuesArray,
             fillTakerTokenAmounts,
@@ -350,7 +333,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 gas,
             },
         );
-        this._throwErrorLogsAsErrors(response.logs);
+        return txHash;
     }
     /**
      * Attempts to fill a specific amount of an order. If the entire amount specified cannot be filled,
@@ -360,10 +343,11 @@ export class ExchangeWrapper extends ContractWrapper {
      * @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 Web3.Provider passed to 0x.js.
+     * @return Transaction hash.
      */
     @decorators.contractCallErrorHandler
     public async fillOrKillOrderAsync(signedOrder: SignedOrder, fillTakerTokenAmount: BigNumber.BigNumber,
-                                      takerAddress: string): Promise<void> {
+                                      takerAddress: string): Promise<string> {
         assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
         assert.isBigNumber('fillTakerTokenAmount', fillTakerTokenAmount);
         await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
@@ -374,7 +358,7 @@ export class ExchangeWrapper extends ContractWrapper {
 
         const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(signedOrder);
 
-        const gas = await exchangeInstance.fillOrKillOrder.estimateGas(
+        const gas = await exchangeInstance.fillOrKillOrder.estimateGasAsync(
             orderAddresses,
             orderValues,
             fillTakerTokenAmount,
@@ -385,7 +369,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 from: takerAddress,
             },
         );
-        const response: ContractResponse = await exchangeInstance.fillOrKillOrder(
+        const txHash = await exchangeInstance.fillOrKillOrder.sendTransactionAsync(
             orderAddresses,
             orderValues,
             fillTakerTokenAmount,
@@ -397,7 +381,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 gas,
             },
         );
-        this._throwErrorLogsAsErrors(response.logs);
+        return txHash;
     }
     /**
      * Batch version of fillOrKill. Allows a taker to specify a batch of orders that will either be atomically
@@ -405,10 +389,11 @@ export class ExchangeWrapper extends ContractWrapper {
      * @param   orderFillOrKillRequests     An array of objects that conform to the OrderFillOrKillRequest interface.
      * @param   takerAddress                The user Ethereum address who would like to fill there orders.
      *                                      Must be available via the supplied Web3.Provider passed to 0x.js.
+     * @return Transaction hash.
      */
     @decorators.contractCallErrorHandler
     public async batchFillOrKillAsync(orderFillOrKillRequests: OrderFillOrKillRequest[],
-                                      takerAddress: string): Promise<void> {
+                                      takerAddress: string): Promise<string> {
         assert.doesConformToSchema('orderFillOrKillRequests', orderFillOrKillRequests,
                                    schemas.orderFillOrKillRequestsSchema);
         const exchangeContractAddresses = _.map(
@@ -419,7 +404,7 @@ export class ExchangeWrapper extends ContractWrapper {
                                        ExchangeContractErrs.BatchOrdersMustHaveSameExchangeAddress);
         await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
         if (_.isEmpty(orderFillOrKillRequests)) {
-            return; // no-op
+            throw new Error(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
         }
         const exchangeInstance = await this._getExchangeContractAsync();
         for (const request of orderFillOrKillRequests) {
@@ -441,7 +426,7 @@ export class ExchangeWrapper extends ContractWrapper {
         const [orderAddresses, orderValues, fillTakerTokenAmounts, vParams, rParams, sParams] =
               _.unzip<any>(orderAddressesValuesAndTakerTokenFillAmounts);
 
-        const gas = await exchangeInstance.batchFillOrKillOrders.estimateGas(
+        const gas = await exchangeInstance.batchFillOrKillOrders.estimateGasAsync(
             orderAddresses,
             orderValues,
             fillTakerTokenAmounts,
@@ -452,7 +437,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 from: takerAddress,
             },
         );
-        const response: ContractResponse = await exchangeInstance.batchFillOrKillOrders(
+        const txHash = await exchangeInstance.batchFillOrKillOrders.sendTransactionAsync(
             orderAddresses,
             orderValues,
             fillTakerTokenAmounts,
@@ -464,18 +449,18 @@ export class ExchangeWrapper extends ContractWrapper {
                 gas,
             },
         );
-        this._throwErrorLogsAsErrors(response.logs);
+        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.
-     * @return                          The amount of the order that was cancelled (in taker token baseUnits).
+     * @return                          Transaction hash.
      */
     @decorators.contractCallErrorHandler
     public async cancelOrderAsync(
-        order: Order|SignedOrder, cancelTakerTokenAmount: BigNumber.BigNumber): Promise<BigNumber.BigNumber> {
+        order: Order|SignedOrder, cancelTakerTokenAmount: BigNumber.BigNumber): Promise<string> {
         assert.doesConformToSchema('order', order, schemas.orderSchema);
         assert.isBigNumber('takerTokenCancelAmount', cancelTakerTokenAmount);
         await assert.isSenderAddressAsync('order.maker', order.maker, this._web3Wrapper);
@@ -484,7 +469,7 @@ export class ExchangeWrapper extends ContractWrapper {
         await this.validateCancelOrderThrowIfInvalidAsync(order, cancelTakerTokenAmount);
 
         const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(order);
-        const gas = await exchangeInstance.cancelOrder.estimateGas(
+        const gas = await exchangeInstance.cancelOrder.estimateGasAsync(
             orderAddresses,
             orderValues,
             cancelTakerTokenAmount,
@@ -492,7 +477,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 from: order.maker,
             },
         );
-        const response: ContractResponse = await exchangeInstance.cancelOrder(
+        const txHash = await exchangeInstance.cancelOrder.sendTransactionAsync(
             orderAddresses,
             orderValues,
             cancelTakerTokenAmount,
@@ -501,19 +486,17 @@ export class ExchangeWrapper extends ContractWrapper {
                 gas,
             },
         );
-        this._throwErrorLogsAsErrors(response.logs);
-        const logFillArgs = response.logs[0].args as LogCancelContractEventArgs;
-        const cancelledTakerTokenAmount = new BigNumber(logFillArgs.cancelledTakerTokenAmount);
-        return cancelledTakerTokenAmount;
+        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.
+     * @return Transaction hash.
      */
     @decorators.contractCallErrorHandler
-    public async batchCancelOrdersAsync(orderCancellationRequests: OrderCancellationRequest[]): Promise<void> {
+    public async batchCancelOrdersAsync(orderCancellationRequests: OrderCancellationRequest[]): Promise<string> {
         assert.doesConformToSchema('orderCancellationRequests', orderCancellationRequests,
                                    schemas.orderCancellationRequestsSchema);
         const exchangeContractAddresses = _.map(
@@ -532,7 +515,7 @@ export class ExchangeWrapper extends ContractWrapper {
             );
         }
         if (_.isEmpty(orderCancellationRequests)) {
-            return; // no-op
+            throw new Error(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
         }
         const exchangeInstance = await this._getExchangeContractAsync();
         const orderAddressesValuesAndTakerTokenCancelAmounts = _.map(orderCancellationRequests, cancellationRequest => {
@@ -544,7 +527,7 @@ export class ExchangeWrapper extends ContractWrapper {
         // We use _.unzip<any> because _.unzip doesn't type check if values have different types :'(
         const [orderAddresses, orderValues, cancelTakerTokenAmounts] =
             _.unzip<any>(orderAddressesValuesAndTakerTokenCancelAmounts);
-        const gas = await exchangeInstance.batchCancelOrders.estimateGas(
+        const gas = await exchangeInstance.batchCancelOrders.estimateGasAsync(
             orderAddresses,
             orderValues,
             cancelTakerTokenAmounts,
@@ -552,7 +535,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 from: maker,
             },
         );
-        const response: ContractResponse = await exchangeInstance.batchCancelOrders(
+        const txHash = await exchangeInstance.batchCancelOrders.sendTransactionAsync(
             orderAddresses,
             orderValues,
             cancelTakerTokenAmounts,
@@ -561,7 +544,7 @@ export class ExchangeWrapper extends ContractWrapper {
                 gas,
             },
         );
-        this._throwErrorLogsAsErrors(response.logs);
+        return txHash;
     }
     /**
      * Subscribe to an event type emitted by the Exchange smart contract
@@ -686,7 +669,7 @@ export class ExchangeWrapper extends ContractWrapper {
         assert.isBigNumber('takerTokenAmount', takerTokenAmount);
         assert.isBigNumber('makerTokenAmount', makerTokenAmount);
         const exchangeInstance = await this._getExchangeContractAsync();
-        const isRoundingError = await exchangeInstance.isRoundingError.call(
+        const isRoundingError = await exchangeInstance.isRoundingError.callAsync(
             fillTakerTokenAmount, takerTokenAmount, makerTokenAmount,
         );
         return isRoundingError;
@@ -703,7 +686,7 @@ export class ExchangeWrapper extends ContractWrapper {
 
         const exchangeInstance = await this._getExchangeContractAsync();
 
-        const isValidSignature = await exchangeInstance.isValidSignature.call(
+        const isValidSignature = await exchangeInstance.isValidSignature.callAsync(
             signerAddressHex,
             dataHex,
             ecSignature.v,
@@ -715,28 +698,22 @@ export class ExchangeWrapper extends ContractWrapper {
     private async _getOrderHashHexUsingContractCallAsync(order: Order|SignedOrder): Promise<string> {
         const exchangeInstance = await this._getExchangeContractAsync();
         const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(order);
-        const orderHashHex = await exchangeInstance.getOrderHash.call(orderAddresses, orderValues);
+        const orderHashHex = await exchangeInstance.getOrderHash.callAsync(orderAddresses, orderValues);
         return orderHashHex;
     }
-    private _throwErrorLogsAsErrors(logs: ContractEvent[]): void {
-        const errEvent = _.find(logs, {event: 'LogError'});
-        if (!_.isUndefined(errEvent)) {
-            const errCode = (errEvent.args as LogErrorContractEventArgs).errorId.toNumber();
-            const errMessage = this._exchangeContractErrCodesToMsg[errCode];
-            throw new Error(errMessage);
-        }
-    }
     private async _getExchangeContractAsync(): Promise<ExchangeContract> {
         if (!_.isUndefined(this._exchangeContractIfExists)) {
             return this._exchangeContractIfExists;
         }
-        const contractInstance = await this._instantiateContractIfExistsAsync((ExchangeArtifacts as any));
+        const contractInstance = await this._instantiateContractIfExistsAsync<ExchangeContract>(
+            artifacts.ExchangeArtifact,
+        );
         this._exchangeContractIfExists = contractInstance as ExchangeContract;
         return this._exchangeContractIfExists;
     }
     private async _getZRXTokenAddressAsync(): Promise<string> {
         const exchangeInstance = await this._getExchangeContractAsync();
-        const ZRXtokenAddress = await exchangeInstance.ZRX_TOKEN_CONTRACT.call();
+        const ZRXtokenAddress = await exchangeInstance.ZRX_TOKEN_CONTRACT.callAsync();
         return ZRXtokenAddress;
     }
 }
diff --git a/src/contract_wrappers/token_registry_wrapper.ts b/src/contract_wrappers/token_registry_wrapper.ts
index 822e69460..528a88e06 100644
--- a/src/contract_wrappers/token_registry_wrapper.ts
+++ b/src/contract_wrappers/token_registry_wrapper.ts
@@ -4,15 +4,15 @@ import {assert} from '../utils/assert';
 import {Token, TokenRegistryContract, TokenMetadata} from '../types';
 import {constants} from '../utils/constants';
 import {ContractWrapper} from './contract_wrapper';
-import * as TokenRegistryArtifacts from '../artifacts/TokenRegistry.json';
+import {artifacts} from '../artifacts';
 
 /**
  * This class includes all the functionality related to interacting with the 0x Token Registry smart contract.
  */
 export class TokenRegistryWrapper extends ContractWrapper {
     private _tokenRegistryContractIfExists?: TokenRegistryContract;
-    constructor(web3Wrapper: Web3Wrapper, gasPrice?: BigNumber.BigNumber) {
-        super(web3Wrapper, gasPrice);
+    constructor(web3Wrapper: Web3Wrapper) {
+        super(web3Wrapper);
     }
     /**
      * Retrieves all the tokens currently listed in the Token Registry smart contract
@@ -35,7 +35,7 @@ export class TokenRegistryWrapper extends ContractWrapper {
      */
     public async getTokenAddressesAsync(): Promise<string[]> {
         const tokenRegistryContract = await this._getTokenRegistryContractAsync();
-        const addresses = await tokenRegistryContract.getTokenAddresses.call();
+        const addresses = await tokenRegistryContract.getTokenAddresses.callAsync();
         return addresses;
     }
     /**
@@ -46,14 +46,14 @@ export class TokenRegistryWrapper extends ContractWrapper {
         assert.isETHAddressHex('address', address);
 
         const tokenRegistryContract = await this._getTokenRegistryContractAsync();
-        const metadata = await tokenRegistryContract.getTokenMetaData.call(address);
+        const metadata = await tokenRegistryContract.getTokenMetaData.callAsync(address);
         const token = this._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.call(symbol);
+        const addressIfExists = await tokenRegistryContract.getTokenAddressBySymbol.callAsync(symbol);
         if (addressIfExists === constants.NULL_ADDRESS) {
             return undefined;
         }
@@ -62,7 +62,7 @@ export class TokenRegistryWrapper extends ContractWrapper {
     public async getTokenAddressByNameIfExistsAsync(name: string): Promise<string|undefined> {
         assert.isString('name', name);
         const tokenRegistryContract = await this._getTokenRegistryContractAsync();
-        const addressIfExists = await tokenRegistryContract.getTokenAddressByName.call(name);
+        const addressIfExists = await tokenRegistryContract.getTokenAddressByName.callAsync(name);
         if (addressIfExists === constants.NULL_ADDRESS) {
             return undefined;
         }
@@ -71,14 +71,14 @@ export class TokenRegistryWrapper extends ContractWrapper {
     public async getTokenBySymbolIfExistsAsync(symbol: string): Promise<Token|undefined> {
         assert.isString('symbol', symbol);
         const tokenRegistryContract = await this._getTokenRegistryContractAsync();
-        const metadata = await tokenRegistryContract.getTokenBySymbol.call(symbol);
+        const metadata = await tokenRegistryContract.getTokenBySymbol.callAsync(symbol);
         const token = this._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.call(name);
+        const metadata = await tokenRegistryContract.getTokenByName.callAsync(name);
         const token = this._createTokenFromMetadata(metadata);
         return token;
     }
@@ -101,7 +101,9 @@ export class TokenRegistryWrapper extends ContractWrapper {
         if (!_.isUndefined(this._tokenRegistryContractIfExists)) {
             return this._tokenRegistryContractIfExists;
         }
-        const contractInstance = await this._instantiateContractIfExistsAsync((TokenRegistryArtifacts as any));
+        const contractInstance = await this._instantiateContractIfExistsAsync<TokenRegistryContract>(
+            artifacts.TokenRegistryArtifact,
+        );
         this._tokenRegistryContractIfExists = contractInstance as TokenRegistryContract;
         return this._tokenRegistryContractIfExists;
     }
diff --git a/src/contract_wrappers/token_transfer_proxy_wrapper.ts b/src/contract_wrappers/token_transfer_proxy_wrapper.ts
index da17d79ff..528d661d1 100644
--- a/src/contract_wrappers/token_transfer_proxy_wrapper.ts
+++ b/src/contract_wrappers/token_transfer_proxy_wrapper.ts
@@ -1,6 +1,6 @@
 import * as _ from 'lodash';
 import {ContractWrapper} from './contract_wrapper';
-import * as TokenTransferProxyArtifacts from '../artifacts/TokenTransferProxy.json';
+import {artifacts} from '../artifacts';
 import {TokenTransferProxyContract} from '../types';
 
 /**
@@ -15,7 +15,7 @@ export class TokenTransferProxyWrapper extends ContractWrapper {
      */
     public async isAuthorizedAsync(exchangeContractAddress: string): Promise<boolean> {
         const tokenTransferProxyContractInstance = await this._getTokenTransferProxyContractAsync();
-        const isAuthorized = await tokenTransferProxyContractInstance.authorized.call(exchangeContractAddress);
+        const isAuthorized = await tokenTransferProxyContractInstance.authorized.callAsync(exchangeContractAddress);
         return isAuthorized;
     }
     /**
@@ -24,7 +24,7 @@ export class TokenTransferProxyWrapper extends ContractWrapper {
      */
     public async getAuthorizedAddressesAsync(): Promise<string[]> {
         const tokenTransferProxyContractInstance = await this._getTokenTransferProxyContractAsync();
-        const authorizedAddresses = await tokenTransferProxyContractInstance.getAuthorizedAddresses.call();
+        const authorizedAddresses = await tokenTransferProxyContractInstance.getAuthorizedAddresses.callAsync();
         return authorizedAddresses;
     }
     /**
@@ -44,7 +44,9 @@ export class TokenTransferProxyWrapper extends ContractWrapper {
         if (!_.isUndefined(this._tokenTransferProxyContractIfExists)) {
             return this._tokenTransferProxyContractIfExists;
         }
-        const contractInstance = await this._instantiateContractIfExistsAsync((TokenTransferProxyArtifacts as any));
+        const contractInstance = await this._instantiateContractIfExistsAsync<TokenTransferProxyContract>(
+            artifacts.TokenTransferProxyArtifact,
+        );
         this._tokenTransferProxyContractIfExists = contractInstance as TokenTransferProxyContract;
         return this._tokenTransferProxyContractIfExists;
     }
diff --git a/src/contract_wrappers/token_wrapper.ts b/src/contract_wrappers/token_wrapper.ts
index f7070f1f4..f1f967286 100644
--- a/src/contract_wrappers/token_wrapper.ts
+++ b/src/contract_wrappers/token_wrapper.ts
@@ -7,8 +7,7 @@ import {utils} from '../utils/utils';
 import {eventUtils} from '../utils/event_utils';
 import {constants} from '../utils/constants';
 import {ContractWrapper} from './contract_wrapper';
-import * as TokenArtifacts from '../artifacts/Token.json';
-import * as TokenTransferProxyArtifacts from '../artifacts/TokenTransferProxy.json';
+import {artifacts} from '../artifacts';
 import {
     TokenContract,
     ZeroExError,
@@ -31,8 +30,8 @@ export class TokenWrapper extends ContractWrapper {
     public UNLIMITED_ALLOWANCE_IN_BASE_UNITS = constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
     private _tokenContractsByAddress: {[address: string]: TokenContract};
     private _tokenLogEventEmitters: ContractEventEmitter[];
-    constructor(web3Wrapper: Web3Wrapper, gasPrice?: BigNumber.BigNumber) {
-        super(web3Wrapper, gasPrice);
+    constructor(web3Wrapper: Web3Wrapper) {
+        super(web3Wrapper);
         this._tokenContractsByAddress = {};
         this._tokenLogEventEmitters = [];
     }
@@ -47,7 +46,7 @@ export class TokenWrapper extends ContractWrapper {
         assert.isETHAddressHex('tokenAddress', tokenAddress);
 
         const tokenContract = await this._getTokenContractAsync(tokenAddress);
-        let balance = await tokenContract.balanceOf.call(ownerAddress);
+        let balance = await tokenContract.balanceOf.callAsync(ownerAddress);
         // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
         balance = new BigNumber(balance);
         return balance;
@@ -60,9 +59,10 @@ export class TokenWrapper extends ContractWrapper {
      *                              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.
+     * @return Transaction hash.
      */
     public async setAllowanceAsync(tokenAddress: string, ownerAddress: string, spenderAddress: string,
-                                   amountInBaseUnits: BigNumber.BigNumber): Promise<void> {
+                                   amountInBaseUnits: BigNumber.BigNumber): Promise<string> {
         await assert.isSenderAddressAsync('ownerAddress', ownerAddress, this._web3Wrapper);
         assert.isETHAddressHex('spenderAddress', spenderAddress);
         assert.isETHAddressHex('tokenAddress', tokenAddress);
@@ -74,10 +74,11 @@ export class TokenWrapper extends ContractWrapper {
         // TODO: Debug issue in testrpc and submit a PR, then remove this hack
         const networkIdIfExists = await this._web3Wrapper.getNetworkIdIfExistsAsync();
         const gas = networkIdIfExists === constants.TESTRPC_NETWORK_ID ? ALLOWANCE_TO_ZERO_GAS_AMOUNT : undefined;
-        await tokenContract.approve(spenderAddress, amountInBaseUnits, {
+        const txHash = await tokenContract.approve.sendTransactionAsync(spenderAddress, amountInBaseUnits, {
             from: ownerAddress,
             gas,
         });
+        return txHash;
     }
     /**
      * Sets the spender's allowance to an unlimited number of baseUnits on behalf of the owner address.
@@ -88,12 +89,14 @@ export class TokenWrapper extends ContractWrapper {
      * @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.
+     * @return Transaction hash.
      */
     public async setUnlimitedAllowanceAsync(tokenAddress: string, ownerAddress: string,
-                                            spenderAddress: string): Promise<void> {
-        await this.setAllowanceAsync(
+                                            spenderAddress: string): Promise<string> {
+        const txHash = await this.setAllowanceAsync(
             tokenAddress, ownerAddress, spenderAddress, this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
         );
+        return txHash;
     }
     /**
      * Retrieves the owners allowance in baseUnits set to the spender's address.
@@ -102,12 +105,13 @@ export class TokenWrapper extends ContractWrapper {
      *                          you would like to retrieve.
      * @param   spenderAddress  The hex encoded user Ethereum address who can spend the allowance you are fetching.
      */
-    public async getAllowanceAsync(tokenAddress: string, ownerAddress: string, spenderAddress: string) {
+    public async getAllowanceAsync(tokenAddress: string, ownerAddress: string,
+                                   spenderAddress: string): Promise<BigNumber.BigNumber> {
         assert.isETHAddressHex('ownerAddress', ownerAddress);
         assert.isETHAddressHex('tokenAddress', tokenAddress);
 
         const tokenContract = await this._getTokenContractAsync(tokenAddress);
-        let allowanceInBaseUnits = await tokenContract.allowance.call(ownerAddress, spenderAddress);
+        let allowanceInBaseUnits = await tokenContract.allowance.callAsync(ownerAddress, spenderAddress);
         // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
         allowanceInBaseUnits = new BigNumber(allowanceInBaseUnits);
         return allowanceInBaseUnits;
@@ -117,7 +121,7 @@ export class TokenWrapper extends ContractWrapper {
      * @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.
      */
-    public async getProxyAllowanceAsync(tokenAddress: string, ownerAddress: string) {
+    public async getProxyAllowanceAsync(tokenAddress: string, ownerAddress: string): Promise<BigNumber.BigNumber> {
         assert.isETHAddressHex('ownerAddress', ownerAddress);
         assert.isETHAddressHex('tokenAddress', tokenAddress);
 
@@ -132,15 +136,17 @@ export class TokenWrapper extends ContractWrapper {
      * @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.
+     * @return Transaction hash.
      */
     public async setProxyAllowanceAsync(tokenAddress: string, ownerAddress: string,
-                                        amountInBaseUnits: BigNumber.BigNumber): Promise<void> {
+                                        amountInBaseUnits: BigNumber.BigNumber): Promise<string> {
         assert.isETHAddressHex('ownerAddress', ownerAddress);
         assert.isETHAddressHex('tokenAddress', tokenAddress);
         assert.isBigNumber('amountInBaseUnits', amountInBaseUnits);
 
         const proxyAddress = await this._getProxyAddressAsync();
-        await this.setAllowanceAsync(tokenAddress, ownerAddress, proxyAddress, amountInBaseUnits);
+        const txHash = await this.setAllowanceAsync(tokenAddress, ownerAddress, proxyAddress, amountInBaseUnits);
+        return txHash;
     }
     /**
      * Sets the 0x proxy contract's allowance to a unlimited number of a tokens' baseUnits on behalf
@@ -150,9 +156,13 @@ export class TokenWrapper extends ContractWrapper {
      * @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.
+     * @return Transaction hash.
      */
-    public async setUnlimitedProxyAllowanceAsync(tokenAddress: string, ownerAddress: string): Promise<void> {
-        await this.setProxyAllowanceAsync(tokenAddress, ownerAddress, this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS);
+    public async setUnlimitedProxyAllowanceAsync(tokenAddress: string, ownerAddress: string): Promise<string> {
+        const txHash = await this.setProxyAllowanceAsync(
+            tokenAddress, ownerAddress, this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
+        );
+        return txHash;
     }
     /**
      * Transfers `amountInBaseUnits` ERC20 tokens from `fromAddress` to `toAddress`.
@@ -160,9 +170,10 @@ export class TokenWrapper extends ContractWrapper {
      * @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.
+     * @return Transaction hash.
      */
     public async transferAsync(tokenAddress: string, fromAddress: string, toAddress: string,
-                               amountInBaseUnits: BigNumber.BigNumber): Promise<void> {
+                               amountInBaseUnits: BigNumber.BigNumber): Promise<string> {
         assert.isETHAddressHex('tokenAddress', tokenAddress);
         await assert.isSenderAddressAsync('fromAddress', fromAddress, this._web3Wrapper);
         assert.isETHAddressHex('toAddress', toAddress);
@@ -175,9 +186,10 @@ export class TokenWrapper extends ContractWrapper {
             throw new Error(ZeroExError.InsufficientBalanceForTransfer);
         }
 
-        await tokenContract.transfer(toAddress, amountInBaseUnits, {
+        const txHash = await tokenContract.transfer.sendTransactionAsync(toAddress, amountInBaseUnits, {
             from: fromAddress,
         });
+        return txHash;
     }
     /**
      * Transfers `amountInBaseUnits` ERC20 tokens from `fromAddress` to `toAddress`.
@@ -190,10 +202,11 @@ export class TokenWrapper extends ContractWrapper {
      *                              `fromAddress` must have set an allowance to the `senderAddress`
      *                              before this call.
      * @param   amountInBaseUnits   The amount (specified in baseUnits) of the token to transfer.
+     * @return Transaction hash.
      */
     public async transferFromAsync(tokenAddress: string, fromAddress: string, toAddress: string,
                                    senderAddress: string, amountInBaseUnits: BigNumber.BigNumber):
-                                   Promise<void> {
+                                   Promise<string> {
         assert.isETHAddressHex('tokenAddress', tokenAddress);
         assert.isETHAddressHex('fromAddress', fromAddress);
         assert.isETHAddressHex('toAddress', toAddress);
@@ -212,9 +225,13 @@ export class TokenWrapper extends ContractWrapper {
             throw new Error(ZeroExError.InsufficientBalanceForTransfer);
         }
 
-        await tokenContract.transferFrom(fromAddress, toAddress, amountInBaseUnits, {
-            from: senderAddress,
-        });
+        const txHash = await tokenContract.transferFrom.sendTransactionAsync(
+            fromAddress, toAddress, amountInBaseUnits,
+            {
+                from: senderAddress,
+            },
+        );
+        return txHash;
     }
     /**
      * Subscribe to an event type emitted by the Token contract.
@@ -267,7 +284,9 @@ export class TokenWrapper extends ContractWrapper {
         if (!_.isUndefined(tokenContract)) {
             return tokenContract;
         }
-        const contractInstance = await this._instantiateContractIfExistsAsync((TokenArtifacts as any), tokenAddress);
+        const contractInstance = await this._instantiateContractIfExistsAsync<TokenContract>(
+            artifacts.TokenArtifact, tokenAddress,
+        );
         tokenContract = contractInstance as TokenContract;
         this._tokenContractsByAddress[tokenAddress] = tokenContract;
         return tokenContract;
@@ -276,7 +295,7 @@ export class TokenWrapper extends ContractWrapper {
         const networkIdIfExists = await this._web3Wrapper.getNetworkIdIfExistsAsync();
         const proxyNetworkConfigsIfExists = _.isUndefined(networkIdIfExists) ?
                                        undefined :
-                                       (TokenTransferProxyArtifacts as any).networks[networkIdIfExists];
+                                       artifacts.TokenTransferProxyArtifact.networks[networkIdIfExists];
         if (_.isUndefined(proxyNetworkConfigsIfExists)) {
             throw new Error(ZeroExError.ContractNotDeployedOnNetwork);
         }
diff --git a/src/globals.d.ts b/src/globals.d.ts
index 9230ab02d..39d0860eb 100644
--- a/src/globals.d.ts
+++ b/src/globals.d.ts
@@ -33,23 +33,11 @@ declare module '*.json' {
     /* tslint:enable */
 }
 
-// truffle-contract declarations
-declare interface ContractInstance {
-    address: string;
-}
-declare interface ContractFactory {
-    setProvider: (providerObj: any) => void;
-    deployed: () => ContractInstance;
-    // Both any's are Web3.CallData, but I was unable to import it in this file
-    defaults: (config: any) => any;
-    at: (address: string) => ContractInstance;
-}
 declare interface Artifact {
-    networks: {[networkId: number]: any};
-}
-declare function contract(artifacts: Artifact): ContractFactory;
-declare module 'truffle-contract' {
-    export = contract;
+    abi: any;
+    networks: {[networkId: number]: {
+        address: string;
+    }};
 }
 
 // find-version declarations
@@ -81,3 +69,18 @@ declare class HDWalletProvider {
 declare module 'truffle-hdwallet-provider' {
     export = HDWalletProvider;
 }
+
+// abi-decoder declarations
+interface DecodedLogArg {
+    name: string;
+    value: string|BigNumber.BigNumber;
+}
+interface DecodedLog {
+    name: string;
+    events: DecodedLogArg[];
+}
+declare module 'abi-decoder' {
+    import * as Web3 from 'web3';
+    const addABI: (abi: Web3.AbiDefinition) => void;
+    const decodeLogs: (logs: Web3.LogEntry[]) => DecodedLog[];
+}
diff --git a/src/index.ts b/src/index.ts
index 6d6e4484c..00d4730da 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -30,4 +30,7 @@ export {
     ContractEventArgs,
     Web3Provider,
     ZeroExConfig,
+    TransactionReceiptWithDecodedLogs,
+    LogWithDecodedArgs,
+    DecodedLogArgs,
 } from './types';
diff --git a/src/types.ts b/src/types.ts
index 2400a9a60..9d3f77127 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -14,6 +14,7 @@ export enum ZeroExError {
     InsufficientWEthBalanceForWithdrawal = 'INSUFFICIENT_WETH_BALANCE_FOR_WITHDRAWAL',
     InvalidJump = 'INVALID_JUMP',
     OutOfGas = 'OUT_OF_GAS',
+    NoNetworkId = 'NO_NETWORK_ID',
 }
 
 /**
@@ -39,137 +40,154 @@ export interface ContractEventObj {
 }
 export type CreateContractEvent = (indexFilterValues: IndexedFilterValues,
                                    subscriptionOpts: SubscriptionOpts) => ContractEventObj;
-export interface ExchangeContract extends ContractInstance {
+export interface ExchangeContract extends Web3.ContractInstance {
     isValidSignature: {
-        call: (signerAddressHex: string, dataHex: string, v: number, r: string, s: string,
-               txOpts?: TxOpts) => Promise<boolean>;
+        callAsync: (signerAddressHex: string, dataHex: string, v: number, r: string, s: string,
+                    txOpts?: TxOpts) => Promise<boolean>;
     };
     LogFill: CreateContractEvent;
     LogCancel: CreateContractEvent;
     LogError: CreateContractEvent;
     ZRX_TOKEN_CONTRACT: {
-        call: () => Promise<string>;
+        callAsync: () => Promise<string>;
     };
     getUnavailableTakerTokenAmount: {
-        call: (orderHash: string) => Promise<BigNumber.BigNumber>;
+        callAsync: (orderHash: string) => Promise<BigNumber.BigNumber>;
     };
     isRoundingError: {
-        call: (fillTakerAmount: BigNumber.BigNumber, takerTokenAmount: BigNumber.BigNumber,
-               makerTokenAmount: BigNumber.BigNumber, txOpts?: TxOpts) => Promise<boolean>;
+        callAsync: (fillTakerAmount: BigNumber.BigNumber, takerTokenAmount: BigNumber.BigNumber,
+                    makerTokenAmount: BigNumber.BigNumber, txOpts?: TxOpts) => Promise<boolean>;
     };
     fillOrder: {
-        (orderAddresses: OrderAddresses, orderValues: OrderValues, fillTakerTokenAmount: BigNumber.BigNumber,
-         shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-         v: number, r: string, s: string, txOpts?: TxOpts): Promise<ContractResponse>;
-        estimateGas: (orderAddresses: OrderAddresses, orderValues: OrderValues,
-                      fillTakerTokenAmount: BigNumber.BigNumber,
-                      shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-                      v: number, r: string, s: string, txOpts?: TxOpts) => Promise<number>;
+        sendTransactionAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
+                               fillTakerTokenAmount: BigNumber.BigNumber,
+                               shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                               v: number, r: string, s: string, txOpts?: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
+                           fillTakerTokenAmount: BigNumber.BigNumber,
+                           shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                           v: number, r: string, s: string, txOpts?: TxOpts) => Promise<number>;
     };
     batchFillOrders: {
-        (orderAddresses: OrderAddresses[], orderValues: OrderValues[], fillTakerTokenAmounts: BigNumber.BigNumber[],
-         shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-         v: number[], r: string[], s: string[], txOpts?: TxOpts): Promise<ContractResponse>;
-        estimateGas: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
-                      fillTakerTokenAmounts: BigNumber.BigNumber[],
-                      shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-                      v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<number>;
+        sendTransactionAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                               fillTakerTokenAmounts: BigNumber.BigNumber[],
+                               shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                               v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                           fillTakerTokenAmounts: BigNumber.BigNumber[],
+                           shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                           v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<number>;
     };
     fillOrdersUpTo: {
-        (orderAddresses: OrderAddresses[], orderValues: OrderValues[], fillTakerTokenAmount: BigNumber.BigNumber,
-         shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-         v: number[], r: string[], s: string[], txOpts?: TxOpts): Promise<ContractResponse>;
-        estimateGas: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
-                      fillTakerTokenAmount: BigNumber.BigNumber,
-                      shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-                      v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<number>;
+        sendTransactionAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                               fillTakerTokenAmount: BigNumber.BigNumber,
+                               shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                               v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                           fillTakerTokenAmount: BigNumber.BigNumber,
+                           shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                           v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<number>;
     };
     cancelOrder: {
-        (orderAddresses: OrderAddresses, orderValues: OrderValues, cancelTakerTokenAmount: BigNumber.BigNumber,
-         txOpts?: TxOpts): Promise<ContractResponse>;
-        estimateGas: (orderAddresses: OrderAddresses, orderValues: OrderValues,
-                      cancelTakerTokenAmount: BigNumber.BigNumber,
-                      txOpts?: TxOpts) => Promise<number>;
+        sendTransactionAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
+                               cancelTakerTokenAmount: BigNumber.BigNumber, txOpts?: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
+                           cancelTakerTokenAmount: BigNumber.BigNumber,
+                           txOpts?: TxOpts) => Promise<number>;
     };
     batchCancelOrders: {
-        (orderAddresses: OrderAddresses[], orderValues: OrderValues[], cancelTakerTokenAmounts: BigNumber.BigNumber[],
-         txOpts?: TxOpts): Promise<ContractResponse>;
-        estimateGas: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
-                      cancelTakerTokenAmounts: BigNumber.BigNumber[],
-                      txOpts?: TxOpts) => Promise<number>;
+        sendTransactionAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                               cancelTakerTokenAmounts: BigNumber.BigNumber[], txOpts?: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                           cancelTakerTokenAmounts: BigNumber.BigNumber[],
+                           txOpts?: TxOpts) => Promise<number>;
     };
     fillOrKillOrder: {
-        (orderAddresses: OrderAddresses, orderValues: OrderValues, fillTakerTokenAmount: BigNumber.BigNumber,
-         v: number, r: string, s: string, txOpts?: TxOpts): Promise<ContractResponse>;
-        estimateGas: (orderAddresses: OrderAddresses, orderValues: OrderValues,
-                      fillTakerTokenAmount: BigNumber.BigNumber,
-                      v: number, r: string, s: string, txOpts?: TxOpts) => Promise<number>;
+        sendTransactionAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
+                               fillTakerTokenAmount: BigNumber.BigNumber,
+                               v: number, r: string, s: string, txOpts?: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
+                           fillTakerTokenAmount: BigNumber.BigNumber,
+                           v: number, r: string, s: string, txOpts?: TxOpts) => Promise<number>;
     };
     batchFillOrKillOrders: {
-        (orderAddresses: OrderAddresses[], orderValues: OrderValues[], fillTakerTokenAmounts: BigNumber.BigNumber[],
-         v: number[], r: string[], s: string[], txOpts: TxOpts): Promise<ContractResponse>;
-        estimateGas: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
-                      fillTakerTokenAmounts: BigNumber.BigNumber[],
-                      v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<number>;
+        sendTransactionAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                               fillTakerTokenAmounts: BigNumber.BigNumber[],
+                               v: number[], r: string[], s: string[], txOpts: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                           fillTakerTokenAmounts: BigNumber.BigNumber[],
+                           v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<number>;
     };
     filled: {
-        call: (orderHash: string) => Promise<BigNumber.BigNumber>;
+        callAsync: (orderHash: string) => Promise<BigNumber.BigNumber>;
     };
     cancelled: {
-        call: (orderHash: string) => Promise<BigNumber.BigNumber>;
+        callAsync: (orderHash: string) => Promise<BigNumber.BigNumber>;
     };
     getOrderHash: {
-        call: (orderAddresses: OrderAddresses, orderValues: OrderValues) => Promise<string>;
+        callAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues) => Promise<string>;
     };
 }
 
-export interface TokenContract extends ContractInstance {
+export interface TokenContract extends Web3.ContractInstance {
     Transfer: CreateContractEvent;
     Approval: CreateContractEvent;
     balanceOf: {
-        call: (address: string) => Promise<BigNumber.BigNumber>;
+        callAsync: (address: string) => Promise<BigNumber.BigNumber>;
     };
     allowance: {
-        call: (ownerAddress: string, allowedAddress: string) => Promise<BigNumber.BigNumber>;
+        callAsync: (ownerAddress: string, allowedAddress: string) => Promise<BigNumber.BigNumber>;
+    };
+    transfer: {
+        sendTransactionAsync: (toAddress: string, amountInBaseUnits: BigNumber.BigNumber,
+                               txOpts?: TxOpts) => Promise<string>;
+    };
+    transferFrom: {
+        sendTransactionAsync: (fromAddress: string, toAddress: string, amountInBaseUnits: BigNumber.BigNumber,
+                               txOpts?: TxOpts) => Promise<string>;
+    };
+    approve: {
+        sendTransactionAsync: (proxyAddress: string, amountInBaseUnits: BigNumber.BigNumber,
+                               txOpts?: TxOpts) => Promise<string>;
     };
-    transfer: (toAddress: string, amountInBaseUnits: BigNumber.BigNumber, txOpts?: TxOpts) => Promise<boolean>;
-    transferFrom: (fromAddress: string, toAddress: string, amountInBaseUnits: BigNumber.BigNumber,
-                   txOpts?: TxOpts) => Promise<boolean>;
-    approve: (proxyAddress: string, amountInBaseUnits: BigNumber.BigNumber, txOpts?: TxOpts) => Promise<void>;
 }
 
-export interface TokenRegistryContract extends ContractInstance {
+export interface TokenRegistryContract extends Web3.ContractInstance {
     getTokenMetaData: {
-        call: (address: string) => Promise<TokenMetadata>;
+        callAsync: (address: string) => Promise<TokenMetadata>;
     };
     getTokenAddresses: {
-        call: () => Promise<string[]>;
+        callAsync: () => Promise<string[]>;
     };
     getTokenAddressBySymbol: {
-        call: (symbol: string) => Promise<string>;
+        callAsync: (symbol: string) => Promise<string>;
     };
     getTokenAddressByName: {
-        call: (name: string) => Promise<string>;
+        callAsync: (name: string) => Promise<string>;
     };
     getTokenBySymbol: {
-        call: (symbol: string) => Promise<TokenMetadata>;
+        callAsync: (symbol: string) => Promise<TokenMetadata>;
     };
     getTokenByName: {
-        call: (name: string) => Promise<TokenMetadata>;
+        callAsync: (name: string) => Promise<TokenMetadata>;
     };
 }
 
-export interface EtherTokenContract extends ContractInstance {
-    deposit: (txOpts: TxOpts) => Promise<void>;
-    withdraw: (amount: BigNumber.BigNumber, txOpts: TxOpts) => Promise<void>;
+export interface EtherTokenContract extends Web3.ContractInstance {
+    deposit: {
+        sendTransactionAsync: (txOpts: TxOpts) => Promise<string>;
+    };
+    withdraw: {
+        sendTransactionAsync: (amount: BigNumber.BigNumber, txOpts: TxOpts) => Promise<string>;
+    };
 }
 
-export interface TokenTransferProxyContract extends ContractInstance {
+export interface TokenTransferProxyContract extends Web3.ContractInstance {
     getAuthorizedAddresses: {
-        call: () => Promise<string[]>;
+        callAsync: () => Promise<string[]>;
     };
     authorized: {
-        call: (address: string) => Promise<boolean>;
+        callAsync: (address: string) => Promise<boolean>;
     };
 }
 
@@ -209,10 +227,7 @@ export enum ExchangeContractErrs {
     InsufficientRemainingFillAmount = 'INSUFFICIENT_REMAINING_FILL_AMOUNT',
     MultipleTakerTokensInFillUpToDisallowed = 'MULTIPLE_TAKER_TOKENS_IN_FILL_UP_TO_DISALLOWED',
     BatchOrdersMustHaveSameExchangeAddress = 'BATCH_ORDERS_MUST_HAVE_SAME_EXCHANGE_ADDRESS',
-}
-
-export interface ContractResponse {
-    logs: ContractEvent[];
+    BatchOrdersMustHaveAtLeastOneItem = 'BATCH_ORDERS_MUST_HAVE_AT_LEAST_ONE_ITEM',
 }
 
 export interface ContractEvent {
@@ -349,14 +364,6 @@ export interface OrderFillRequest {
 
 export type AsyncMethod = (...args: any[]) => Promise<any>;
 
-export interface ContractInstance {
-    address: string;
-}
-
-export interface Artifact {
-    networks: {[networkId: number]: any};
-}
-
 export interface ContractEventEmitter {
     watch: (eventCallback: EventCallback) => void;
     stopWatchingAsync: () => Promise<void>;
@@ -373,14 +380,6 @@ export interface ExchangeContractByAddress {
     [address: string]: ExchangeContract;
 }
 
-export interface ContractArtifact {
-    networks: {
-        [networkId: number]: {
-            address: string;
-        };
-    };
-}
-
 export interface JSONRPCPayload {
     params: any[];
     method: string;
@@ -389,3 +388,25 @@ export interface JSONRPCPayload {
 export interface ZeroExConfig {
     gasPrice?: BigNumber.BigNumber; // Gas price to use with every transaction
 }
+
+export type TransactionReceipt = Web3.TransactionReceipt;
+
+export enum AbiType {
+    Function = 'function',
+    Constructor = 'constructor',
+    Event = 'event',
+    Fallback = 'fallback',
+}
+
+export interface DecodedLogArgs {
+    [argName: string]: ContractEventArg;
+}
+
+export interface LogWithDecodedArgs extends Web3.LogEntry {
+    args: DecodedLogArgs;
+    event: string;
+}
+
+export interface TransactionReceiptWithDecodedLogs extends Web3.TransactionReceipt {
+    logs: LogWithDecodedArgs[];
+}
diff --git a/src/web3_wrapper.ts b/src/web3_wrapper.ts
index 61bac45c9..7b9a28a7d 100644
--- a/src/web3_wrapper.ts
+++ b/src/web3_wrapper.ts
@@ -2,13 +2,17 @@ import * as _ from 'lodash';
 import * as Web3 from 'web3';
 import * as BigNumber from 'bignumber.js';
 import promisify = require('es6-promisify');
+import {ZeroExError} from './types';
+import {Contract} from './contract';
 
 export class Web3Wrapper {
     private web3: Web3;
+    private defaults: Partial<Web3.TxData>;
     private networkIdIfExists?: number;
-    constructor(provider: Web3.Provider) {
+    constructor(provider: Web3.Provider, defaults: Partial<Web3.TxData>) {
         this.web3 = new Web3();
         this.web3.setProvider(provider);
+        this.defaults = defaults;
     }
     public setProvider(provider: Web3.Provider) {
         delete this.networkIdIfExists;
@@ -25,6 +29,10 @@ export class Web3Wrapper {
         const nodeVersion = await promisify(this.web3.version.getNode)();
         return nodeVersion;
     }
+    public async getTransactionReceiptAsync(txHash: string): Promise<Web3.TransactionReceipt> {
+        const transactionReceipt = await promisify(this.web3.eth.getTransactionReceipt)(txHash);
+        return transactionReceipt;
+    }
     public getCurrentProvider(): Web3.Provider {
         return this.web3.currentProvider;
     }
@@ -41,6 +49,30 @@ export class Web3Wrapper {
             return undefined;
         }
     }
+    public async getContractInstanceFromArtifactAsync<A extends Web3.ContractInstance>(artifact: Artifact,
+                                                                                       address?: string): Promise<A> {
+        let contractAddress: string;
+        if (_.isUndefined(address)) {
+            const networkIdIfExists = await this.getNetworkIdIfExistsAsync();
+            if (_.isUndefined(networkIdIfExists)) {
+                throw new Error(ZeroExError.NoNetworkId);
+            }
+            if (_.isUndefined(artifact.networks[networkIdIfExists])) {
+                throw new Error(ZeroExError.ContractNotDeployedOnNetwork);
+            }
+            contractAddress = artifact.networks[networkIdIfExists].address.toLowerCase();
+        } else {
+            contractAddress = address;
+        }
+        const doesContractExist = await this.doesContractExistAtAddressAsync(contractAddress);
+        if (!doesContractExist) {
+            throw new Error(ZeroExError.ContractDoesNotExist);
+        }
+        const contractInstance = this.getContractInstance<A>(
+            artifact.abi, contractAddress,
+        );
+        return contractInstance;
+    }
     public toWei(ethAmount: BigNumber.BigNumber): BigNumber.BigNumber {
         const balanceWei = this.web3.toWei(ethAmount, 'ether');
         return balanceWei;
@@ -68,6 +100,11 @@ export class Web3Wrapper {
         const addresses: string[] = await promisify(this.web3.eth.getAccounts)();
         return addresses;
     }
+    private getContractInstance<A extends Web3.ContractInstance>(abi: Web3.ContractAbi, address: string): A {
+        const web3ContractInstance = this.web3.eth.contract(abi).at(address);
+        const contractInstance = new Contract(web3ContractInstance, this.defaults) as any as A;
+        return contractInstance;
+    }
     private async getNetworkAsync(): Promise<number> {
         const networkId = await promisify(this.web3.version.getNetwork)();
         return networkId;