Switch over to Lerna + Yarn Workspaces setup for a mono-repo approach

11 files changed, 789 insertions, 0 deletions

diff --git a/packages/0x.js/src/utils/abi_decoder.ts b/packages/0x.js/src/utils/abi_decoder.ts
new file mode 100644
index 000000000..840ad9be0
--- /dev/null
+++ b/packages/0x.js/src/utils/abi_decoder.ts
@@ -0,0 +1,68 @@
+import * as Web3 from 'web3';
+import * as _ from 'lodash';
+import BigNumber from 'bignumber.js';
+import {AbiType, DecodedLogArgs, LogWithDecodedArgs, RawLog, SolidityTypes, ContractEventArgs} from '../types';
+import * as SolidityCoder from 'web3/lib/solidity/coder';
+
+export class AbiDecoder {
+    private savedABIs: Web3.AbiDefinition[] = [];
+    private methodIds: {[signatureHash: string]: Web3.EventAbi} = {};
+    constructor(abiArrays: Web3.AbiDefinition[][]) {
+        _.map(abiArrays, this.addABI.bind(this));
+    }
+    // This method can only decode logs from the 0x & ERC20 smart contracts
+    public tryToDecodeLogOrNoop<ArgsType extends ContractEventArgs>(
+        log: Web3.LogEntry): LogWithDecodedArgs<ArgsType>|RawLog {
+        const methodId = log.topics[0];
+        const event = this.methodIds[methodId];
+        if (_.isUndefined(event)) {
+            return log;
+        }
+        const logData = log.data;
+        const decodedParams: DecodedLogArgs = {};
+        let dataIndex = 0;
+        let topicsIndex = 1;
+
+        const nonIndexedInputs = _.filter(event.inputs, input => !input.indexed);
+        const dataTypes = _.map(nonIndexedInputs, input => input.type);
+        const decodedData = SolidityCoder.decodeParams(dataTypes, logData.slice('0x'.length));
+
+        _.map(event.inputs, (param: Web3.EventParameter) => {
+            // Indexed parameters are stored in topics. Non-indexed ones in decodedData
+            let value = param.indexed ? log.topics[topicsIndex++] : decodedData[dataIndex++];
+            if (param.type === SolidityTypes.Address) {
+                value = this.padZeros(new BigNumber(value).toString(16));
+            } else if (param.type === SolidityTypes.Uint256 ||
+                       param.type === SolidityTypes.Uint8 ||
+                       param.type === SolidityTypes.Uint ) {
+                value = new BigNumber(value);
+            }
+            decodedParams[param.name] = value;
+        });
+
+        return {
+            ...log,
+            event: event.name,
+            args: decodedParams,
+        };
+    }
+    private addABI(abiArray: Web3.AbiDefinition[]): void {
+        _.map(abiArray, (abi: Web3.AbiDefinition) => {
+            if (abi.type === AbiType.Event) {
+                const signature = `${abi.name}(${_.map(abi.inputs, input => input.type).join(',')})`;
+                const signatureHash = new Web3().sha3(signature);
+                this.methodIds[signatureHash] = abi;
+            }
+        });
+        this.savedABIs = this.savedABIs.concat(abiArray);
+    }
+    private padZeros(address: string) {
+        let formatted = address;
+        if (_.startsWith(formatted, '0x')) {
+            formatted = formatted.slice(2);
+        }
+
+        formatted = _.padStart(formatted, 40, '0');
+        return `0x${formatted}`;
+    }
+}
diff --git a/packages/0x.js/src/utils/assert.ts b/packages/0x.js/src/utils/assert.ts
new file mode 100644
index 000000000..e5c9439f3
--- /dev/null
+++ b/packages/0x.js/src/utils/assert.ts
@@ -0,0 +1,101 @@
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+import {SchemaValidator, Schema} from '0x-json-schemas';
+import {Web3Wrapper} from '../web3_wrapper';
+import {signatureUtils} from '../utils/signature_utils';
+import {ECSignature} from '../types';
+
+const HEX_REGEX = /^0x[0-9A-F]*$/i;
+
+export const assert = {
+    isBigNumber(variableName: string, value: BigNumber): void {
+        const isBigNumber = _.isObject(value) && (value as any).isBigNumber;
+        this.assert(isBigNumber, this.typeAssertionMessage(variableName, 'BigNumber', value));
+    },
+    isValidBaseUnitAmount(variableName: string, value: BigNumber) {
+        assert.isBigNumber(variableName, value);
+        const hasDecimals = value.decimalPlaces() !== 0;
+        this.assert(
+            !hasDecimals, `${variableName} should be in baseUnits (no decimals), found value: ${value.toNumber()}`,
+        );
+    },
+    isValidSignature(orderHash: string, ecSignature: ECSignature, signerAddress: string) {
+        const isValidSignature = signatureUtils.isValidSignature(orderHash, ecSignature, signerAddress);
+        this.assert(isValidSignature, `Expected order with hash '${orderHash}' to have a valid signature`);
+    },
+    isUndefined(value: any, variableName?: string): void {
+        this.assert(_.isUndefined(value), this.typeAssertionMessage(variableName, 'undefined', value));
+    },
+    isString(variableName: string, value: string): void {
+        this.assert(_.isString(value), this.typeAssertionMessage(variableName, 'string', value));
+    },
+    isFunction(variableName: string, value: any): void {
+        this.assert(_.isFunction(value), this.typeAssertionMessage(variableName, 'function', value));
+    },
+    isHexString(variableName: string, value: string): void {
+        this.assert(_.isString(value) && HEX_REGEX.test(value),
+            this.typeAssertionMessage(variableName, 'HexString', value));
+    },
+    isETHAddressHex(variableName: string, value: string): void {
+        const web3 = new Web3();
+        this.assert(web3.isAddress(value), this.typeAssertionMessage(variableName, 'ETHAddressHex', value));
+        this.assert(
+            web3.isAddress(value) && value.toLowerCase() === value,
+            `Checksummed addresses are not supported. Convert ${variableName} to lower case before passing`,
+        );
+    },
+    doesBelongToStringEnum(variableName: string, value: string,
+                           stringEnum: any /* There is no base type for every string enum */): void {
+        const doesBelongToStringEnum = !_.isUndefined(stringEnum[value]);
+        const enumValues = _.keys(stringEnum);
+        const enumValuesAsStrings = _.map(enumValues, enumValue => `'${enumValue}'`);
+        const enumValuesAsString = enumValuesAsStrings.join(', ');
+        assert.assert(
+            doesBelongToStringEnum,
+            `Expected ${variableName} to be one of: ${enumValuesAsString}, encountered: ${value}`,
+        );
+    },
+    async isSenderAddressAsync(variableName: string, senderAddressHex: string,
+                               web3Wrapper: Web3Wrapper): Promise<void> {
+        assert.isETHAddressHex(variableName, senderAddressHex);
+        const isSenderAddressAvailable = await web3Wrapper.isSenderAddressAvailableAsync(senderAddressHex);
+        assert.assert(isSenderAddressAvailable,
+            `Specified ${variableName} ${senderAddressHex} isn't available through the supplied web3 provider`,
+        );
+    },
+    async isUserAddressAvailableAsync(web3Wrapper: Web3Wrapper): Promise<void> {
+        const availableAddresses = await web3Wrapper.getAvailableAddressesAsync();
+        this.assert(!_.isEmpty(availableAddresses), 'No addresses were available on the provided web3 provider');
+    },
+    hasAtMostOneUniqueValue(value: any[], errMsg: string): void {
+        this.assert(_.uniq(value).length <= 1, errMsg);
+    },
+    isNumber(variableName: string, value: number): void {
+        this.assert(_.isFinite(value), this.typeAssertionMessage(variableName, 'number', value));
+    },
+    isBoolean(variableName: string, value: boolean): void {
+        this.assert(_.isBoolean(value), this.typeAssertionMessage(variableName, 'boolean', value));
+    },
+    isWeb3Provider(variableName: string, value: Web3.Provider): void {
+        const isWeb3Provider = _.isFunction((value as any).send) || _.isFunction((value as any).sendAsync);
+        this.assert(isWeb3Provider, this.typeAssertionMessage(variableName, 'Web3.Provider', value));
+    },
+    doesConformToSchema(variableName: string, value: any, schema: Schema): void {
+        const schemaValidator = new SchemaValidator();
+        const validationResult = schemaValidator.validate(value, schema);
+        const hasValidationErrors = validationResult.errors.length > 0;
+        const msg = `Expected ${variableName} to conform to schema ${schema.id}
+Encountered: ${JSON.stringify(value, null, '\t')}
+Validation errors: ${validationResult.errors.join(', ')}`;
+        this.assert(!hasValidationErrors, msg);
+    },
+    assert(condition: boolean, message: string): void {
+        if (!condition) {
+            throw new Error(message);
+        }
+    },
+    typeAssertionMessage(variableName: string, type: string, value: any): string {
+        return `Expected ${variableName} to be of type ${type}, encountered: ${value}`;
+    },
+};
diff --git a/packages/0x.js/src/utils/constants.ts b/packages/0x.js/src/utils/constants.ts
new file mode 100644
index 000000000..3de3f5bc1
--- /dev/null
+++ b/packages/0x.js/src/utils/constants.ts
@@ -0,0 +1,11 @@
+import BigNumber from 'bignumber.js';
+
+export const constants = {
+    NULL_ADDRESS: '0x0000000000000000000000000000000000000000',
+    TESTRPC_NETWORK_ID: 50,
+    MAX_DIGITS_IN_UNSIGNED_256_INT: 78,
+    INVALID_JUMP_PATTERN: 'invalid JUMP at',
+    OUT_OF_GAS_PATTERN: 'out of gas',
+    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
new file mode 100644
index 000000000..ec750b891
--- /dev/null
+++ b/packages/0x.js/src/utils/decorators.ts
@@ -0,0 +1,35 @@
+import * as _ from 'lodash';
+import {constants} from './constants';
+import {AsyncMethod, ZeroExError} from '../types';
+
+export const decorators = {
+    /**
+     * Source: https://stackoverflow.com/a/29837695/3546986
+     */
+    contractCallErrorHandler(target: object,
+                             key: string|symbol,
+                             descriptor: TypedPropertyDescriptor<AsyncMethod>,
+    ): 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) {
+                if (_.includes(error.message, constants.INVALID_JUMP_PATTERN)) {
+                    throw new Error(ZeroExError.InvalidJump);
+                }
+                if (_.includes(error.message, constants.OUT_OF_GAS_PATTERN)) {
+                    throw new Error(ZeroExError.OutOfGas);
+                }
+                throw error;
+            }
+        };
+
+        return descriptor;
+    },
+};
diff --git a/packages/0x.js/src/utils/exchange_transfer_simulator.ts b/packages/0x.js/src/utils/exchange_transfer_simulator.ts
new file mode 100644
index 000000000..308ef06db
--- /dev/null
+++ b/packages/0x.js/src/utils/exchange_transfer_simulator.ts
@@ -0,0 +1,88 @@
+import * as _ from 'lodash';
+import BigNumber from 'bignumber.js';
+import {ExchangeContractErrs, TradeSide, TransferType, BlockParamLiteral} from '../types';
+import {TokenWrapper} from '../contract_wrappers/token_wrapper';
+import {BalanceAndProxyAllowanceLazyStore} from '../stores/balance_proxy_allowance_lazy_store';
+
+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;
+    constructor(token: TokenWrapper) {
+        this.store = new BalanceAndProxyAllowanceLazyStore(token);
+        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> {
+        const balance = await this.store.getBalanceAsync(tokenAddress, from);
+        const proxyAllowance = await this.store.getProxyAllowanceAsync(tokenAddress, from);
+        if (proxyAllowance.lessThan(amountInBaseUnits)) {
+            this.throwValidationError(FailureReason.ProxyAllowance, tradeSide, transferType);
+        }
+        if (balance.lessThan(amountInBaseUnits)) {
+            this.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));
+    }
+    private throwValidationError(failureReason: FailureReason, tradeSide: TradeSide,
+                                 transferType: TransferType): Promise<never> {
+        const errMsg = ERR_MSG_MAPPING[failureReason][tradeSide][transferType];
+        throw new Error(errMsg);
+    }
+}
diff --git a/packages/0x.js/src/utils/filter_utils.ts b/packages/0x.js/src/utils/filter_utils.ts
new file mode 100644
index 000000000..e09a95a6e
--- /dev/null
+++ b/packages/0x.js/src/utils/filter_utils.ts
@@ -0,0 +1,82 @@
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+import * as uuid from 'uuid/v4';
+import * as ethUtil from 'ethereumjs-util';
+import * as jsSHA3 from 'js-sha3';
+import {ContractEvents, IndexedFilterValues, SubscriptionOpts} from '../types';
+
+const TOPIC_LENGTH = 32;
+
+export const filterUtils = {
+    generateUUID(): string {
+        return uuid();
+    },
+    getFilter(address: string, eventName: ContractEvents,
+              indexFilterValues: IndexedFilterValues, abi: Web3.ContractAbi,
+              subscriptionOpts?: SubscriptionOpts): Web3.FilterObject {
+        const eventAbi = _.find(abi, {name: eventName}) as Web3.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: Web3.FilterObject = {
+            address,
+            topics,
+        };
+        if (!_.isUndefined(subscriptionOpts)) {
+            filter = {
+                ...subscriptionOpts,
+                ...filter,
+            };
+        }
+        return filter;
+    },
+    getEventSignatureFromAbiByName(eventAbi: Web3.EventAbi, eventName: ContractEvents): string {
+        const types = _.map(eventAbi.inputs, 'type');
+        const signature = `${eventAbi.name}(${types.join(',')})`;
+        return signature;
+    },
+    getTopicsForIndexedArgs(abi: Web3.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: Web3.LogEntry, filter: Web3.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/interval_utils.ts b/packages/0x.js/src/utils/interval_utils.ts
new file mode 100644
index 000000000..62b79f2f5
--- /dev/null
+++ b/packages/0x.js/src/utils/interval_utils.ts
@@ -0,0 +1,20 @@
+import * as _ from 'lodash';
+
+export const intervalUtils = {
+    setAsyncExcludingInterval(fn: () => Promise<void>, intervalMs: number) {
+        let locked = false;
+        const intervalId = setInterval(async () => {
+            if (locked) {
+                return;
+            } else {
+                locked = true;
+                await fn();
+                locked = false;
+            }
+        }, intervalMs);
+        return intervalId;
+    },
+    clearAsyncExcludingInterval(intervalId: NodeJS.Timer): void {
+        clearInterval(intervalId);
+    },
+};
diff --git a/packages/0x.js/src/utils/order_state_utils.ts b/packages/0x.js/src/utils/order_state_utils.ts
new file mode 100644
index 000000000..f82601cae
--- /dev/null
+++ b/packages/0x.js/src/utils/order_state_utils.ts
@@ -0,0 +1,119 @@
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+import {
+    ExchangeContractErrs,
+    SignedOrder,
+    OrderRelevantState,
+    MethodOpts,
+    OrderState,
+    OrderStateValid,
+    OrderStateInvalid,
+} from '../types';
+import {ZeroEx} from '../0x';
+import {TokenWrapper} from '../contract_wrappers/token_wrapper';
+import {ExchangeWrapper} from '../contract_wrappers/exchange_wrapper';
+import {utils} from '../utils/utils';
+import {constants} from '../utils/constants';
+import {OrderFilledCancelledLazyStore} from '../stores/order_filled_cancelled_lazy_store';
+import {BalanceAndProxyAllowanceLazyStore} from '../stores/balance_proxy_allowance_lazy_store';
+
+export class OrderStateUtils {
+    private balanceAndProxyAllowanceLazyStore: BalanceAndProxyAllowanceLazyStore;
+    private orderFilledCancelledLazyStore: OrderFilledCancelledLazyStore;
+    constructor(balanceAndProxyAllowanceLazyStore: BalanceAndProxyAllowanceLazyStore,
+                orderFilledCancelledLazyStore: OrderFilledCancelledLazyStore) {
+        this.balanceAndProxyAllowanceLazyStore = balanceAndProxyAllowanceLazyStore;
+        this.orderFilledCancelledLazyStore = orderFilledCancelledLazyStore;
+    }
+    public async getOrderStateAsync(signedOrder: SignedOrder): Promise<OrderState> {
+        const orderRelevantState = await this.getOrderRelevantStateAsync(signedOrder);
+        const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+        try {
+            this.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.orderFilledCancelledLazyStore as any).exchange as ExchangeWrapper;
+        const zrxTokenAddress = await exchange.getZRXTokenAddressAsync();
+        const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+        const makerBalance = await this.balanceAndProxyAllowanceLazyStore.getBalanceAsync(
+            signedOrder.makerTokenAddress, signedOrder.maker,
+        );
+        const makerProxyAllowance = await this.balanceAndProxyAllowanceLazyStore.getProxyAllowanceAsync(
+            signedOrder.makerTokenAddress, signedOrder.maker,
+        );
+        const makerFeeBalance = await this.balanceAndProxyAllowanceLazyStore.getBalanceAsync(
+            zrxTokenAddress, signedOrder.maker,
+        );
+        const makerFeeProxyAllowance = await this.balanceAndProxyAllowanceLazyStore.getProxyAllowanceAsync(
+            zrxTokenAddress, signedOrder.maker,
+        );
+        const filledTakerTokenAmount = await this.orderFilledCancelledLazyStore.getFilledTakerAmountAsync(orderHash);
+        const canceledTakerTokenAmount = await this.orderFilledCancelledLazyStore.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 fillableMakerTokenAmount = BigNumber.min([makerProxyAllowance, makerBalance]);
+        const remainingFillableMakerTokenAmount = BigNumber.min(fillableMakerTokenAmount, remainingMakerTokenAmount);
+        // TODO: Handle edge case where maker token is ZRX with fee
+        const orderRelevantState = {
+            makerBalance,
+            makerProxyAllowance,
+            makerFeeBalance,
+            makerFeeProxyAllowance,
+            filledTakerTokenAmount,
+            canceledTakerTokenAmount,
+            remainingFillableMakerTokenAmount,
+        };
+        return orderRelevantState;
+    }
+    private validateIfOrderIsValid(signedOrder: SignedOrder, orderRelevantState: OrderRelevantState): void {
+        const unavailableTakerTokenAmount = orderRelevantState.canceledTakerTokenAmount.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);
+            }
+        }
+        // TODO Add linear function solver when maker token is ZRX #badass
+        // Return the max amount that's fillable
+    }
+}
diff --git a/packages/0x.js/src/utils/order_validation_utils.ts b/packages/0x.js/src/utils/order_validation_utils.ts
new file mode 100644
index 000000000..f03703c4e
--- /dev/null
+++ b/packages/0x.js/src/utils/order_validation_utils.ts
@@ -0,0 +1,166 @@
+import * as _ from 'lodash';
+import BigNumber from 'bignumber.js';
+import {ExchangeContractErrs, SignedOrder, Order, ZeroExError, TradeSide, TransferType} from '../types';
+import {ZeroEx} from '../0x';
+import {TokenWrapper} from '../contract_wrappers/token_wrapper';
+import {ExchangeWrapper} from '../contract_wrappers/exchange_wrapper';
+import {utils} from '../utils/utils';
+import {constants} from '../utils/constants';
+import {ExchangeTransferSimulator} from './exchange_transfer_simulator';
+
+export class OrderValidationUtils {
+    private tokenWrapper: TokenWrapper;
+    private exchangeWrapper: ExchangeWrapper;
+    constructor(tokenWrapper: TokenWrapper, exchangeWrapper: ExchangeWrapper) {
+        this.tokenWrapper = tokenWrapper;
+        this.exchangeWrapper = exchangeWrapper;
+    }
+    public async validateOrderFillableOrThrowAsync(
+        exchangeTradeEmulator: ExchangeTransferSimulator, signedOrder: SignedOrder, zrxTokenAddress: string,
+        expectedFillTakerTokenAmount?: BigNumber): Promise<void> {
+        const orderHash = utils.getOrderHashHex(signedOrder);
+        const unavailableTakerTokenAmount = await this.exchangeWrapper.getUnavailableTakerAmountAsync(orderHash);
+        this.validateRemainingFillAmountNotZeroOrThrow(
+            signedOrder.takerTokenAmount, unavailableTakerTokenAmount,
+        );
+        this.validateOrderNotExpiredOrThrow(signedOrder.expirationUnixTimestampSec);
+        let fillTakerTokenAmount = signedOrder.takerTokenAmount.minus(unavailableTakerTokenAmount);
+        if (!_.isUndefined(expectedFillTakerTokenAmount)) {
+            fillTakerTokenAmount = expectedFillTakerTokenAmount;
+        }
+        const fillMakerTokenAmount = this.getPartialAmount(
+            fillTakerTokenAmount,
+            signedOrder.takerTokenAmount,
+            signedOrder.makerTokenAmount,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            signedOrder.makerTokenAddress, signedOrder.maker, signedOrder.taker, fillMakerTokenAmount,
+            TradeSide.Maker, TransferType.Trade,
+        );
+        const makerFeeAmount = this.getPartialAmount(
+            fillTakerTokenAmount,
+            signedOrder.takerTokenAmount,
+            signedOrder.makerFee,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            zrxTokenAddress, signedOrder.maker, signedOrder.feeRecipient, makerFeeAmount,
+            TradeSide.Maker, TransferType.Fee,
+        );
+    }
+    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 = utils.getOrderHashHex(signedOrder);
+        if (!ZeroEx.isValidSignature(orderHash, signedOrder.ecSignature, signedOrder.maker)) {
+            throw new Error(ZeroExError.InvalidSignature);
+        }
+        const unavailableTakerTokenAmount = await this.exchangeWrapper.getUnavailableTakerAmountAsync(orderHash);
+        this.validateRemainingFillAmountNotZeroOrThrow(
+            signedOrder.takerTokenAmount, unavailableTakerTokenAmount,
+        );
+        if (signedOrder.taker !== constants.NULL_ADDRESS && signedOrder.taker !== takerAddress) {
+            throw new Error(ExchangeContractErrs.TransactionSenderIsNotFillOrderTaker);
+        }
+        this.validateOrderNotExpiredOrThrow(signedOrder.expirationUnixTimestampSec);
+        const remainingTakerTokenAmount = signedOrder.takerTokenAmount.minus(unavailableTakerTokenAmount);
+        const filledTakerTokenAmount = remainingTakerTokenAmount.lessThan(fillTakerTokenAmount) ?
+                                       remainingTakerTokenAmount :
+                                       fillTakerTokenAmount;
+        await this.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);
+        }
+    }
+    public async validateCancelOrderThrowIfInvalidAsync(order: Order,
+                                                        cancelTakerTokenAmount: BigNumber,
+                                                        unavailableTakerTokenAmount: BigNumber,
+    ): Promise<void> {
+        if (cancelTakerTokenAmount.eq(0)) {
+            throw new Error(ExchangeContractErrs.OrderCancelAmountZero);
+        }
+        if (order.takerTokenAmount.eq(unavailableTakerTokenAmount)) {
+            throw new Error(ExchangeContractErrs.OrderAlreadyCancelledOrFilled);
+        }
+        const currentUnixTimestampSec = utils.getCurrentUnixTimestamp();
+        if (order.expirationUnixTimestampSec.lessThan(currentUnixTimestampSec)) {
+            throw new Error(ExchangeContractErrs.OrderCancelExpired);
+        }
+    }
+    public async validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+        exchangeTradeEmulator: ExchangeTransferSimulator, signedOrder: SignedOrder,
+        fillTakerTokenAmount: BigNumber, senderAddress: string, zrxTokenAddress: string): Promise<void> {
+        const fillMakerTokenAmount = this.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 = this.getPartialAmount(
+            fillTakerTokenAmount,
+            signedOrder.takerTokenAmount,
+            signedOrder.makerFee,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            zrxTokenAddress, signedOrder.maker, signedOrder.feeRecipient, makerFeeAmount, TradeSide.Maker,
+            TransferType.Fee,
+        );
+        const takerFeeAmount = this.getPartialAmount(
+            fillTakerTokenAmount,
+            signedOrder.takerTokenAmount,
+            signedOrder.takerFee,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            zrxTokenAddress, senderAddress, signedOrder.feeRecipient, takerFeeAmount, TradeSide.Taker,
+            TransferType.Fee,
+        );
+    }
+    private validateRemainingFillAmountNotZeroOrThrow(
+        takerTokenAmount: BigNumber, unavailableTakerTokenAmount: BigNumber,
+    ) {
+        if (takerTokenAmount.eq(unavailableTakerTokenAmount)) {
+            throw new Error(ExchangeContractErrs.OrderRemainingFillAmountZero);
+        }
+    }
+    private validateOrderNotExpiredOrThrow(expirationUnixTimestampSec: BigNumber) {
+        const currentUnixTimestampSec = utils.getCurrentUnixTimestamp();
+        if (expirationUnixTimestampSec.lessThan(currentUnixTimestampSec)) {
+            throw new Error(ExchangeContractErrs.OrderFillExpired);
+        }
+    }
+    private getPartialAmount(numerator: BigNumber, denominator: BigNumber,
+                             target: BigNumber): BigNumber {
+        const fillMakerTokenAmount = numerator
+                                     .mul(target)
+                                     .div(denominator)
+                                     .round(0);
+        return fillMakerTokenAmount;
+    }
+}
diff --git a/packages/0x.js/src/utils/signature_utils.ts b/packages/0x.js/src/utils/signature_utils.ts
new file mode 100644
index 000000000..d066f8bf0
--- /dev/null
+++ b/packages/0x.js/src/utils/signature_utils.ts
@@ -0,0 +1,44 @@
+import * as ethUtil from 'ethereumjs-util';
+import {ECSignature} from '../types';
+
+export const signatureUtils = {
+    isValidSignature(data: string, signature: ECSignature, signerAddress: string): boolean {
+        const dataBuff = ethUtil.toBuffer(data);
+        const msgHashBuff = ethUtil.hashPersonalMessage(dataBuff);
+        try {
+            const pubKey = ethUtil.ecrecover(
+                msgHashBuff,
+                signature.v,
+                ethUtil.toBuffer(signature.r),
+                ethUtil.toBuffer(signature.s));
+            const retrievedAddress = ethUtil.bufferToHex(ethUtil.pubToAddress(pubKey));
+            return retrievedAddress === signerAddress;
+        } catch (err) {
+            return false;
+        }
+    },
+    parseSignatureHexAsVRS(signatureHex: string): ECSignature {
+        const signatureBuffer = ethUtil.toBuffer(signatureHex);
+        let v = signatureBuffer[0];
+        if (v < 27) {
+            v += 27;
+        }
+        const r = signatureBuffer.slice(1, 33);
+        const s = signatureBuffer.slice(33, 65);
+        const ecSignature: ECSignature = {
+            v,
+            r: ethUtil.bufferToHex(r),
+            s: ethUtil.bufferToHex(s),
+        };
+        return ecSignature;
+    },
+    parseSignatureHexAsRSV(signatureHex: string): ECSignature {
+        const {v, r, s} = ethUtil.fromRpcSig(signatureHex);
+        const ecSignature: ECSignature = {
+            v,
+            r: ethUtil.bufferToHex(r),
+            s: ethUtil.bufferToHex(s),
+        };
+        return ecSignature;
+    },
+};
diff --git a/packages/0x.js/src/utils/utils.ts b/packages/0x.js/src/utils/utils.ts
new file mode 100644
index 000000000..280f3e979
--- /dev/null
+++ b/packages/0x.js/src/utils/utils.ts
@@ -0,0 +1,55 @@
+import * as _ from 'lodash';
+import * as ethABI from 'ethereumjs-abi';
+import * as ethUtil from 'ethereumjs-util';
+import {Order, SignedOrder, SolidityTypes} from '../types';
+import BigNumber from 'bignumber.js';
+import BN = require('bn.js');
+
+export const utils = {
+    /**
+     * Converts BigNumber instance to BN
+     * The only reason we convert to BN is to remain compatible with `ethABI. soliditySHA3` that
+     * expects values of Solidity type `uint` to be passed as type `BN`.
+     * We do not use BN anywhere else in the codebase.
+     */
+    bigNumberToBN(value: BigNumber) {
+        return new BN(value.toString(), 10);
+    },
+    consoleLog(message: string): void {
+        // tslint:disable-next-line: no-console
+        console.log(message);
+    },
+    isParityNode(nodeVersion: string): boolean {
+        return _.includes(nodeVersion, 'Parity');
+    },
+    isTestRpc(nodeVersion: string): boolean {
+        return _.includes(nodeVersion, 'TestRPC');
+    },
+    spawnSwitchErr(name: string, value: any): Error {
+        return new Error(`Unexpected switch value: ${value} encountered for ${name}`);
+    },
+    getOrderHashHex(order: Order|SignedOrder): string {
+        const orderParts = [
+            {value: order.exchangeContractAddress, type: SolidityTypes.Address},
+            {value: order.maker, type: SolidityTypes.Address},
+            {value: order.taker, type: SolidityTypes.Address},
+            {value: order.makerTokenAddress, type: SolidityTypes.Address},
+            {value: order.takerTokenAddress, type: SolidityTypes.Address},
+            {value: order.feeRecipient, type: SolidityTypes.Address},
+            {value: utils.bigNumberToBN(order.makerTokenAmount), type: SolidityTypes.Uint256},
+            {value: utils.bigNumberToBN(order.takerTokenAmount), type: SolidityTypes.Uint256},
+            {value: utils.bigNumberToBN(order.makerFee), type: SolidityTypes.Uint256},
+            {value: utils.bigNumberToBN(order.takerFee), type: SolidityTypes.Uint256},
+            {value: utils.bigNumberToBN(order.expirationUnixTimestampSec), type: SolidityTypes.Uint256},
+            {value: utils.bigNumberToBN(order.salt), type: SolidityTypes.Uint256},
+        ];
+        const types = _.map(orderParts, o => o.type);
+        const values = _.map(orderParts, o => o.value);
+        const hashBuff = ethABI.soliditySHA3(types, values);
+        const hashHex = ethUtil.bufferToHex(hashBuff);
+        return hashHex;
+    },
+    getCurrentUnixTimestamp(): BigNumber {
+        return new BigNumber(Date.now() / 1000);
+    },
+};