Merge branch 'development' into feature/forwarder-helper/init

* development: (187 commits)
  Remove trailing slash
  Fix linter
  Stop nesting interfaces and add necessary type exports
  Remove duplicate type and remove nested interface
  Add support for rending the Tuple type
  Add missing keyu
  Remove excessive timestamp
  Improve doc commebnt
  Remove docs catch-all endpoint
  Fix comments
  Look for all TS mapped types
  Add catch and exit with non-zero
  Remove superfluous dep
  Fix CHANGELOG entry
  Fix double assignment
  Upgrade Typedoc to 0.12.0, which works with TS 3.x
  Fix prettier issues
  Enable dry run of release publishing and handle git tags existing
  update yarn.lock
  Missing/superfluous type exports from connect
  ...

17 files changed, 635 insertions, 392 deletions

diff --git a/packages/order-utils/src/abstract/abstract_balance_and_proxy_allowance_fetcher.ts b/packages/order-utils/src/abstract/abstract_balance_and_proxy_allowance_fetcher.ts
index b2760d98e..c7f06abad 100644
--- a/packages/order-utils/src/abstract/abstract_balance_and_proxy_allowance_fetcher.ts
+++ b/packages/order-utils/src/abstract/abstract_balance_and_proxy_allowance_fetcher.ts
@@ -1,6 +1,23 @@
 import { BigNumber } from '@0xproject/utils';
 
+/**
+ * An abstract class to be implemented in order to use OrderStateUtils. The class that
+ * implements this interface must be capable of fetching the balance and proxyAllowance
+ * for an Ethereum address and assetData
+ */
 export abstract class AbstractBalanceAndProxyAllowanceFetcher {
+    /**
+     * Get balance of assetData for userAddress
+     * @param assetData AssetData for which to fetch the balance
+     * @param userAddress Ethereum address for which to fetch the balance
+     * @return Balance amount in base units
+     */
     public abstract async getBalanceAsync(assetData: string, userAddress: string): Promise<BigNumber>;
+    /**
+     * Get the 0x asset proxy allowance of assetData for userAddress
+     * @param assetData AssetData for which to fetch the allowance
+     * @param userAddress Ethereum address for which to fetch the allowance
+     * @return Allowance amount in base units
+     */
     public abstract async getProxyAllowanceAsync(assetData: string, userAddress: string): Promise<BigNumber>;
 }
diff --git a/packages/order-utils/src/abstract/abstract_order_filled_cancelled_fetcher.ts b/packages/order-utils/src/abstract/abstract_order_filled_cancelled_fetcher.ts
index 865ea4e43..fbc1c4718 100644
--- a/packages/order-utils/src/abstract/abstract_order_filled_cancelled_fetcher.ts
+++ b/packages/order-utils/src/abstract/abstract_order_filled_cancelled_fetcher.ts
@@ -1,7 +1,22 @@
 import { BigNumber } from '@0xproject/utils';
 
+/**
+ * An abstract class to be implemented in order to use OrderStateUtils. The class that
+ * implements this interface must be capable of fetching the amount filled of an order
+ * and whether it's been cancelled.
+ */
 export abstract class AbstractOrderFilledCancelledFetcher {
+    /**
+     * Get the amount of the order's takerToken amount already filled
+     * @param orderHash OrderHash of order we are interested in
+     * @return FilledTakerAmount
+     */
     public abstract async getFilledTakerAmountAsync(orderHash: string): Promise<BigNumber>;
+    /**
+     * Whether an order is cancelled
+     * @param orderHash OrderHash of order we are interested in
+     * @return Whether or not the order is cancelled
+     */
     public abstract async isOrderCancelledAsync(orderHash: string): Promise<boolean>;
     public abstract getZRXAssetData(): string;
 }
diff --git a/packages/order-utils/src/artifacts.ts b/packages/order-utils/src/artifacts.ts
index 3d2d1e953..735cc2403 100644
--- a/packages/order-utils/src/artifacts.ts
+++ b/packages/order-utils/src/artifacts.ts
@@ -1,4 +1,4 @@
-import { ContractArtifact } from '@0xproject/sol-compiler';
+import { ContractArtifact } from 'ethereum-types';
 
 import * as DummyERC20Token from './artifacts/DummyERC20Token.json';
 import * as ERC20Proxy from './artifacts/ERC20Proxy.json';
diff --git a/packages/order-utils/src/eip712_utils.ts b/packages/order-utils/src/eip712_utils.ts
index 2594e6d6d..b303c93dc 100644
--- a/packages/order-utils/src/eip712_utils.ts
+++ b/packages/order-utils/src/eip712_utils.ts
@@ -18,14 +18,14 @@ const EIP712_DOMAIN_SCHEMA: EIP712Schema = {
     ],
 };
 
-export const EIP712Utils = {
+export const eip712Utils = {
     /**
      * Compiles the EIP712Schema and returns the hash of the schema.
      * @param   schema The EIP712 schema.
      * @return  The hash of the compiled schema
      */
     compileSchema(schema: EIP712Schema): Buffer {
-        const eip712Schema = EIP712Utils._encodeType(schema);
+        const eip712Schema = eip712Utils._encodeType(schema);
         const eip712SchemaHashBuffer = crypto.solSHA3([eip712Schema]);
         return eip712SchemaHashBuffer;
     },
@@ -36,25 +36,47 @@ export const EIP712Utils = {
      * @return  The hash of an EIP712 message with domain separator prefixed
      */
     createEIP712Message(hashStruct: Buffer, contractAddress: string): Buffer {
-        const domainSeparatorHashBuffer = EIP712Utils._getDomainSeparatorHashBuffer(contractAddress);
+        const domainSeparatorHashBuffer = eip712Utils._getDomainSeparatorHashBuffer(contractAddress);
         const messageBuff = crypto.solSHA3([EIP191_PREFIX, domainSeparatorHashBuffer, hashStruct]);
         return messageBuff;
     },
+    /**
+     * Pad an address to 32 bytes
+     * @param address Address to pad
+     * @return padded address
+     */
     pad32Address(address: string): Buffer {
         const addressBuffer = ethUtil.toBuffer(address);
-        const addressPadded = EIP712Utils.pad32Buffer(addressBuffer);
+        const addressPadded = eip712Utils.pad32Buffer(addressBuffer);
         return addressPadded;
     },
+    /**
+     * Pad an buffer to 32 bytes
+     * @param buffer Address to pad
+     * @return padded buffer
+     */
     pad32Buffer(buffer: Buffer): Buffer {
         const bufferPadded = ethUtil.setLengthLeft(buffer, EIP712_VALUE_LENGTH);
         return bufferPadded;
     },
+    /**
+     * Hash together a EIP712 schema with the corresponding data
+     * @param schema EIP712-compliant schema
+     * @param data Data the complies to the schema
+     * @return A buffer containing the SHA256 hash of the schema and encoded data
+     */
+    structHash(schema: EIP712Schema, data: { [key: string]: any }): Buffer {
+        const encodedData = eip712Utils._encodeData(schema, data);
+        const schemaHash = eip712Utils.compileSchema(schema);
+        const hashBuffer = crypto.solSHA3([schemaHash, ...encodedData]);
+        return hashBuffer;
+    },
     _getDomainSeparatorSchemaBuffer(): Buffer {
-        return EIP712Utils.compileSchema(EIP712_DOMAIN_SCHEMA);
+        return eip712Utils.compileSchema(EIP712_DOMAIN_SCHEMA);
     },
     _getDomainSeparatorHashBuffer(exchangeAddress: string): Buffer {
-        const domainSeparatorSchemaBuffer = EIP712Utils._getDomainSeparatorSchemaBuffer();
-        const encodedData = EIP712Utils._encodeData(EIP712_DOMAIN_SCHEMA, {
+        const domainSeparatorSchemaBuffer = eip712Utils._getDomainSeparatorSchemaBuffer();
+        const encodedData = eip712Utils._encodeData(EIP712_DOMAIN_SCHEMA, {
             name: EIP712_DOMAIN_NAME,
             version: EIP712_DOMAIN_VERSION,
             verifyingContract: exchangeAddress,
@@ -77,17 +99,11 @@ export const EIP712Utils = {
             } else if (parameter.type === EIP712Types.Uint256) {
                 encodedValues.push(value);
             } else if (parameter.type === EIP712Types.Address) {
-                encodedValues.push(EIP712Utils.pad32Address(value));
+                encodedValues.push(eip712Utils.pad32Address(value));
             } else {
                 throw new Error(`Unable to encode ${parameter.type}`);
             }
         }
         return encodedValues;
     },
-    structHash(schema: EIP712Schema, data: { [key: string]: any }): Buffer {
-        const encodedData = EIP712Utils._encodeData(schema, data);
-        const schemaHash = EIP712Utils.compileSchema(schema);
-        const hashBuffer = crypto.solSHA3([schemaHash, ...encodedData]);
-        return hashBuffer;
-    },
 };
diff --git a/packages/order-utils/src/exchange_transfer_simulator.ts b/packages/order-utils/src/exchange_transfer_simulator.ts
index c3a4f9c2a..81c849c64 100644
--- a/packages/order-utils/src/exchange_transfer_simulator.ts
+++ b/packages/order-utils/src/exchange_transfer_simulator.ts
@@ -33,6 +33,10 @@ const ERR_MSG_MAPPING = {
     },
 };
 
+/**
+ * An exchange transfer simulator which simulates asset transfers exactly how the
+ * 0x exchange contract would do them.
+ */
 export class ExchangeTransferSimulator {
     private readonly _store: AbstractBalanceAndProxyAllowanceLazyStore;
     private static _throwValidationError(
@@ -43,6 +47,11 @@ export class ExchangeTransferSimulator {
         const errMsg = ERR_MSG_MAPPING[failureReason][tradeSide][transferType];
         throw new Error(errMsg);
     }
+    /**
+     * Instantiate a ExchangeTransferSimulator
+     * @param store A class that implements AbstractBalanceAndProxyAllowanceLazyStore
+     * @return an instance of ExchangeTransferSimulator
+     */
     constructor(store: AbstractBalanceAndProxyAllowanceLazyStore) {
         this._store = store;
     }
diff --git a/packages/order-utils/src/index.ts b/packages/order-utils/src/index.ts
index 2b1c92973..354299304 100644
--- a/packages/order-utils/src/index.ts
+++ b/packages/order-utils/src/index.ts
@@ -1,29 +1,48 @@
 export { orderHashUtils } from './order_hash';
-export {
-    isValidSignatureAsync,
-    isValidPresignedSignatureAsync,
-    isValidWalletSignatureAsync,
-    isValidValidatorSignatureAsync,
-    isValidECSignature,
-    ecSignOrderHashAsync,
-    addSignedMessagePrefix,
-    parseECSignature,
-} from './signature_utils';
-export { orderFactory } from './order_factory';
-export { constants } from './constants';
-export { crypto } from './crypto';
+export { signatureUtils } from './signature_utils';
 export { generatePseudoRandomSalt } from './salt';
-export { CreateOrderOpts, OrderError, EIP712Parameter, EIP712Schema, EIP712Types } from './types';
-export { AbstractBalanceAndProxyAllowanceFetcher } from './abstract/abstract_balance_and_proxy_allowance_fetcher';
-export { AbstractOrderFilledCancelledFetcher } from './abstract/abstract_order_filled_cancelled_fetcher';
-export { BalanceAndProxyAllowanceLazyStore } from './store/balance_and_proxy_allowance_lazy_store';
-export { OrderFilledCancelledLazyStore } from './store/order_filled_cancelled_lazy_store';
-export { RemainingFillableCalculator } from './remaining_fillable_calculator';
-export { OrderStateUtils } from './order_state_utils';
 export { assetDataUtils } from './asset_data_utils';
-export { EIP712Utils } from './eip712_utils';
-export { OrderValidationUtils } from './order_validation_utils';
-export { ExchangeTransferSimulator } from './exchange_transfer_simulator';
+export { eip712Utils } from './eip712_utils';
 export { marketUtils } from './market_utils';
 export { rateUtils } from './rate_utils';
 export { sortingUtils } from './sorting_utils';
+
+export { OrderStateUtils } from './order_state_utils';
+export { AbstractBalanceAndProxyAllowanceFetcher } from './abstract/abstract_balance_and_proxy_allowance_fetcher';
+export { AbstractBalanceAndProxyAllowanceLazyStore } from './abstract/abstract_balance_and_proxy_allowance_lazy_store';
+export { AbstractOrderFilledCancelledFetcher } from './abstract/abstract_order_filled_cancelled_fetcher';
+export { AbstractOrderFilledCancelledLazyStore } from './abstract/abstract_order_filled_cancelled_lazy_store';
+
+export { OrderValidationUtils } from './order_validation_utils';
+export { ExchangeTransferSimulator } from './exchange_transfer_simulator';
+export { BalanceAndProxyAllowanceLazyStore } from './store/balance_and_proxy_allowance_lazy_store';
+export { OrderFilledCancelledLazyStore } from './store/order_filled_cancelled_lazy_store';
+
+export { Provider, JSONRPCRequestPayload, JSONRPCErrorCallback, JSONRPCResponsePayload } from 'ethereum-types';
+export {
+    SignedOrder,
+    Order,
+    OrderRelevantState,
+    OrderState,
+    ECSignature,
+    ERC20AssetData,
+    ERC721AssetData,
+    AssetProxyId,
+    SignerType,
+    SignatureType,
+    OrderStateValid,
+    OrderStateInvalid,
+    ExchangeContractErrs,
+} from '@0xproject/types';
+export {
+    OrderError,
+    EIP712Parameter,
+    EIP712Schema,
+    EIP712Types,
+    TradeSide,
+    TransferType,
+    FindFeeOrdersThatCoverFeesForTargetOrdersOpts,
+    FindOrdersThatCoverMakerAssetFillAmountOpts,
+    FeeOrdersAndRemainingFeeAmount,
+    OrdersAndRemainingFillAmount,
+} from './types';
diff --git a/packages/order-utils/src/market_utils.ts b/packages/order-utils/src/market_utils.ts
index b31a2b135..4a664cb14 100644
--- a/packages/order-utils/src/market_utils.ts
+++ b/packages/order-utils/src/market_utils.ts
@@ -5,7 +5,12 @@ import * as _ from 'lodash';
 
 import { assert } from './assert';
 import { constants } from './constants';
-import { FindFeeOrdersThatCoverFeesForTargetOrdersOpts, FindOrdersThatCoverMakerAssetFillAmountOpts } from './types';
+import {
+    FeeOrdersAndRemainingFeeAmount,
+    FindFeeOrdersThatCoverFeesForTargetOrdersOpts,
+    FindOrdersThatCoverMakerAssetFillAmountOpts,
+    OrdersAndRemainingFillAmount,
+} from './types';
 
 export const marketUtils = {
     /**
@@ -22,7 +27,7 @@ export const marketUtils = {
         orders: T[],
         makerAssetFillAmount: BigNumber,
         opts?: FindOrdersThatCoverMakerAssetFillAmountOpts,
-    ): { resultOrders: T[]; remainingFillAmount: BigNumber } {
+    ): OrdersAndRemainingFillAmount<T> {
         assert.doesConformToSchema('orders', orders, schemas.ordersSchema);
         assert.isValidBaseUnitAmount('makerAssetFillAmount', makerAssetFillAmount);
         // try to get remainingFillableMakerAssetAmounts from opts, if it's not there, use makerAssetAmount values from orders
@@ -84,7 +89,7 @@ export const marketUtils = {
         orders: T[],
         feeOrders: T[],
         opts?: FindFeeOrdersThatCoverFeesForTargetOrdersOpts,
-    ): { resultFeeOrders: T[]; remainingFeeAmount: BigNumber } {
+    ): FeeOrdersAndRemainingFeeAmount<T> {
         assert.doesConformToSchema('orders', orders, schemas.ordersSchema);
         assert.doesConformToSchema('feeOrders', feeOrders, schemas.ordersSchema);
         // try to get remainingFillableMakerAssetAmounts from opts, if it's not there, use makerAssetAmount values from orders
diff --git a/packages/order-utils/src/monorepo_scripts/postpublish.ts b/packages/order-utils/src/monorepo_scripts/postpublish.ts
deleted file mode 100644
index dcb99d0f7..000000000
--- a/packages/order-utils/src/monorepo_scripts/postpublish.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-import { postpublishUtils } from '@0xproject/monorepo-scripts';
-
-import * as packageJSON from '../package.json';
-import * as tsConfigJSON from '../tsconfig.json';
-
-const cwd = `${__dirname}/..`;
-// tslint:disable-next-line:no-floating-promises
-postpublishUtils.runAsync(packageJSON, tsConfigJSON, cwd);
diff --git a/packages/order-utils/src/monorepo_scripts/stage_docs.ts b/packages/order-utils/src/monorepo_scripts/stage_docs.ts
deleted file mode 100644
index e732ac8eb..000000000
--- a/packages/order-utils/src/monorepo_scripts/stage_docs.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-import { postpublishUtils } from '@0xproject/monorepo-scripts';
-
-import * as packageJSON from '../package.json';
-import * as tsConfigJSON from '../tsconfig.json';
-
-const cwd = `${__dirname}/..`;
-// tslint:disable-next-line:no-floating-promises
-postpublishUtils.publishDocsToStagingAsync(packageJSON, tsConfigJSON, cwd);
diff --git a/packages/order-utils/src/order_factory.ts b/packages/order-utils/src/order_factory.ts
index 4a6f3924b..46a69ae4d 100644
--- a/packages/order-utils/src/order_factory.ts
+++ b/packages/order-utils/src/order_factory.ts
@@ -6,7 +6,7 @@ import * as _ from 'lodash';
 import { constants } from './constants';
 import { orderHashUtils } from './order_hash';
 import { generatePseudoRandomSalt } from './salt';
-import { ecSignOrderHashAsync } from './signature_utils';
+import { signatureUtils } from './signature_utils';
 import { CreateOrderOpts } from './types';
 
 export const orderFactory = {
@@ -58,7 +58,12 @@ export const orderFactory = {
             createOrderOpts,
         );
         const orderHash = orderHashUtils.getOrderHashHex(order);
-        const signature = await ecSignOrderHashAsync(provider, orderHash, makerAddress, SignerType.Default);
+        const signature = await signatureUtils.ecSignOrderHashAsync(
+            provider,
+            orderHash,
+            makerAddress,
+            SignerType.Default,
+        );
         const signedOrder: SignedOrder = _.assign(order, { signature });
         return signedOrder;
     },
diff --git a/packages/order-utils/src/order_hash.ts b/packages/order-utils/src/order_hash.ts
index 54c500653..8e98f8767 100644
--- a/packages/order-utils/src/order_hash.ts
+++ b/packages/order-utils/src/order_hash.ts
@@ -3,7 +3,7 @@ import { Order, SignedOrder } from '@0xproject/types';
 import * as _ from 'lodash';
 
 import { assert } from './assert';
-import { EIP712Utils } from './eip712_utils';
+import { eip712Utils } from './eip712_utils';
 import { EIP712Schema, EIP712Types } from './types';
 
 const INVALID_TAKER_FORMAT = 'instance.takerAddress is not of a type(s) string';
@@ -69,11 +69,11 @@ export const orderHashUtils = {
      * @return  The resulting orderHash from hashing the supplied order as a Buffer
      */
     getOrderHashBuffer(order: SignedOrder | Order): Buffer {
-        const orderParamsHashBuff = EIP712Utils.structHash(EIP712_ORDER_SCHEMA, order);
-        const orderHashBuff = EIP712Utils.createEIP712Message(orderParamsHashBuff, order.exchangeAddress);
+        const orderParamsHashBuff = eip712Utils.structHash(EIP712_ORDER_SCHEMA, order);
+        const orderHashBuff = eip712Utils.createEIP712Message(orderParamsHashBuff, order.exchangeAddress);
         return orderHashBuff;
     },
     _getOrderSchemaBuffer(): Buffer {
-        return EIP712Utils.compileSchema(EIP712_ORDER_SCHEMA);
+        return eip712Utils.compileSchema(EIP712_ORDER_SCHEMA);
     },
 };
diff --git a/packages/order-utils/src/order_state_utils.ts b/packages/order-utils/src/order_state_utils.ts
index 18fc18bf6..a0e24acf0 100644
--- a/packages/order-utils/src/order_state_utils.ts
+++ b/packages/order-utils/src/order_state_utils.ts
@@ -91,6 +91,14 @@ export class OrderStateUtils {
         }
         return { isValid: true };
     }
+    /**
+     * Instantiate OrderStateUtils
+     * @param balanceAndProxyAllowanceFetcher A class that is capable of fetching balances
+     * and proxyAllowances for Ethereum addresses. It must implement AbstractBalanceAndProxyAllowanceFetcher
+     * @param orderFilledCancelledFetcher A class that is capable of fetching whether an order
+     * is cancelled and how much of it has been filled. It must implement AbstractOrderFilledCancelledFetcher
+     * @return Instance of OrderStateUtils
+     */
     constructor(
         balanceAndProxyAllowanceFetcher: AbstractBalanceAndProxyAllowanceFetcher,
         orderFilledCancelledFetcher: AbstractOrderFilledCancelledFetcher,
@@ -98,6 +106,14 @@ export class OrderStateUtils {
         this._balanceAndProxyAllowanceFetcher = balanceAndProxyAllowanceFetcher;
         this._orderFilledCancelledFetcher = orderFilledCancelledFetcher;
     }
+    /**
+     * Get the orderState for an "open" order (i.e where takerAddress=NULL_ADDRESS)
+     * This method will only check the maker's balance/allowance to calculate the
+     * OrderState.
+     * @param signedOrder The order of interest
+     * @return State relevant to the signedOrder, as well as whether the signedOrder is "valid".
+     * Validity is defined as a non-zero amount of the order can still be filled.
+     */
     public async getOpenOrderStateAsync(signedOrder: SignedOrder): Promise<OrderState> {
         const orderRelevantState = await this.getOpenOrderRelevantStateAsync(signedOrder);
         const orderHash = orderHashUtils.getOrderHashHex(signedOrder);
@@ -129,6 +145,11 @@ export class OrderStateUtils {
             return orderState;
         }
     }
+    /**
+     * Get state relevant to an order (i.e makerBalance, makerAllowance, filledTakerAssetAmount, etc...
+     * @param signedOrder Order of interest
+     * @return An instance of OrderRelevantState
+     */
     public async getOpenOrderRelevantStateAsync(signedOrder: SignedOrder): Promise<OrderRelevantState> {
         const isMaker = true;
         const sidedOrderRelevantState = await this._getSidedOrderRelevantStateAsync(
@@ -151,6 +172,12 @@ export class OrderStateUtils {
         };
         return orderRelevantState;
     }
+    /**
+     * Get the max amount of the supplied order's takerAmount that could still be filled
+     * @param signedOrder Order of interest
+     * @param takerAddress Hypothetical taker of the order
+     * @return fillableTakerAssetAmount
+     */
     public async getMaxFillableTakerAssetAmountAsync(
         signedOrder: SignedOrder,
         takerAddress: string,
@@ -183,32 +210,6 @@ export class OrderStateUtils {
 
         return fillableTakerAssetAmount;
     }
-    public async getMaxFillableTakerAssetAmountForFailingOrderAsync(
-        signedOrder: SignedOrder,
-        takerAddress: string,
-    ): Promise<BigNumber> {
-        // Get min of taker balance & allowance
-        const takerAssetBalanceOfTaker = await this._balanceAndProxyAllowanceFetcher.getBalanceAsync(
-            signedOrder.takerAssetData,
-            takerAddress,
-        );
-        const takerAssetAllowanceOfTaker = await this._balanceAndProxyAllowanceFetcher.getProxyAllowanceAsync(
-            signedOrder.takerAssetData,
-            takerAddress,
-        );
-        const minTakerAssetAmount = BigNumber.min([takerAssetBalanceOfTaker, takerAssetAllowanceOfTaker]);
-
-        // get remainingFillAmount
-        const orderHash = orderHashUtils.getOrderHashHex(signedOrder);
-        const filledTakerAssetAmount = await this._orderFilledCancelledFetcher.getFilledTakerAmountAsync(orderHash);
-        const remainingFillTakerAssetAmount = signedOrder.takerAssetAmount.minus(filledTakerAssetAmount);
-
-        if (minTakerAssetAmount.gte(remainingFillTakerAssetAmount)) {
-            return remainingFillTakerAssetAmount;
-        } else {
-            return minTakerAssetAmount;
-        }
-    }
     private async _getSidedOrderRelevantStateAsync(
         isMakerSide: boolean,
         signedOrder: SignedOrder,
diff --git a/packages/order-utils/src/order_validation_utils.ts b/packages/order-utils/src/order_validation_utils.ts
index 67d747081..972e6f6d6 100644
--- a/packages/order-utils/src/order_validation_utils.ts
+++ b/packages/order-utils/src/order_validation_utils.ts
@@ -9,11 +9,21 @@ import { AbstractOrderFilledCancelledFetcher } from './abstract/abstract_order_f
 import { constants } from './constants';
 import { ExchangeTransferSimulator } from './exchange_transfer_simulator';
 import { orderHashUtils } from './order_hash';
-import { isValidSignatureAsync } from './signature_utils';
+import { signatureUtils } from './signature_utils';
 import { utils } from './utils';
 
+/**
+ * A utility class for validating orders
+ */
 export class OrderValidationUtils {
     private readonly _orderFilledCancelledFetcher: AbstractOrderFilledCancelledFetcher;
+    /**
+     * A Typescript implementation mirroring the implementation of isRoundingError in the
+     * Exchange smart contract
+     * @param numerator Numerator value. When used to check an order, pass in `takerAssetFilledAmount`
+     * @param denominator Denominator value.  When used to check an order, pass in `order.takerAssetAmount`
+     * @param target Target value. When used to check an order, pass in `order.makerAssetAmount`
+     */
     public static isRoundingError(numerator: BigNumber, denominator: BigNumber, target: BigNumber): boolean {
         // Solidity's mulmod() in JS
         // Source: https://solidity.readthedocs.io/en/latest/units-and-global-variables.html#mathematical-and-cryptographic-functions
@@ -31,6 +41,15 @@ export class OrderValidationUtils {
         const isError = errPercentageTimes1000000.gt(1000);
         return isError;
     }
+    /**
+     * Validate that the maker & taker have sufficient balances/allowances
+     * to fill the supplied order to the fillTakerAssetAmount amount
+     * @param exchangeTradeEmulator ExchangeTradeEmulator to use
+     * @param signedOrder SignedOrder to test
+     * @param fillTakerAssetAmount Amount of takerAsset to fill the signedOrder
+     * @param senderAddress Sender of the fillOrder tx
+     * @param zrxAssetData AssetData for the ZRX token
+     */
     public static async validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
         exchangeTradeEmulator: ExchangeTransferSimulator,
         signedOrder: SignedOrder,
@@ -104,9 +123,22 @@ export class OrderValidationUtils {
             throw new Error(RevertReason.OrderUnfillable);
         }
     }
+    /**
+     * Instantiate OrderValidationUtils
+     * @param orderFilledCancelledFetcher A module that implements the AbstractOrderFilledCancelledFetcher
+     * @return An instance of OrderValidationUtils
+     */
     constructor(orderFilledCancelledFetcher: AbstractOrderFilledCancelledFetcher) {
         this._orderFilledCancelledFetcher = orderFilledCancelledFetcher;
     }
+    /**
+     * Validate if the supplied order is fillable, and throw if it isn't
+     * @param exchangeTradeEmulator ExchangeTradeEmulator instance
+     * @param signedOrder SignedOrder of interest
+     * @param zrxAssetData ZRX assetData
+     * @param expectedFillTakerTokenAmount If supplied, this call will make sure this amount is fillable.
+     * If it isn't supplied, we check if the order is fillable for a non-zero amount
+     */
     public async validateOrderFillableOrThrowAsync(
         exchangeTradeEmulator: ExchangeTransferSimulator,
         signedOrder: SignedOrder,
@@ -132,6 +164,15 @@ export class OrderValidationUtils {
             zrxAssetData,
         );
     }
+    /**
+     * Validate a call to FillOrder and throw if it wouldn't succeed
+     * @param exchangeTradeEmulator ExchangeTradeEmulator to use
+     * @param provider Web3 provider to use for JSON RPC requests
+     * @param signedOrder SignedOrder of interest
+     * @param fillTakerAssetAmount Amount we'd like to fill the order for
+     * @param takerAddress The taker of the order
+     * @param zrxAssetData ZRX asset data
+     */
     public async validateFillOrderThrowIfInvalidAsync(
         exchangeTradeEmulator: ExchangeTransferSimulator,
         provider: Provider,
@@ -147,7 +188,7 @@ export class OrderValidationUtils {
             throw new Error(RevertReason.InvalidTakerAmount);
         }
         const orderHash = orderHashUtils.getOrderHashHex(signedOrder);
-        const isValid = await isValidSignatureAsync(
+        const isValid = await signatureUtils.isValidSignatureAsync(
             provider,
             orderHash,
             signedOrder.signature,
@@ -187,6 +228,15 @@ export class OrderValidationUtils {
         }
         return filledTakerTokenAmount;
     }
+    /**
+     * Validate a call to fillOrKillOrder and throw if it would fail
+     * @param exchangeTradeEmulator ExchangeTradeEmulator to use
+     * @param provider Web3 provider to use for JSON RPC requests
+     * @param signedOrder SignedOrder of interest
+     * @param fillTakerAssetAmount Amount we'd like to fill the order for
+     * @param takerAddress The taker of the order
+     * @param zrxAssetData ZRX asset data
+     */
     public async validateFillOrKillOrderThrowIfInvalidAsync(
         exchangeTradeEmulator: ExchangeTransferSimulator,
         provider: Provider,
diff --git a/packages/order-utils/src/signature_utils.ts b/packages/order-utils/src/signature_utils.ts
index 870aef2ed..40bbcef98 100644
--- a/packages/order-utils/src/signature_utils.ts
+++ b/packages/order-utils/src/signature_utils.ts
@@ -13,329 +13,353 @@ import { IWalletContract } from './generated_contract_wrappers/i_wallet';
 import { OrderError } from './types';
 import { utils } from './utils';
 
-/**
- * Verifies that the provided signature is valid according to the 0x Protocol smart contracts
- * @param   data          The hex encoded data signed by the supplied signature.
- * @param   signature     A hex encoded 0x Protocol signature made up of: [TypeSpecificData][SignatureType].
- *          E.g [vrs][SignatureType.EIP712]
- * @param   signerAddress The hex encoded address that signed the data, producing the supplied signature.
- * @return  Whether the signature is valid for the supplied signerAddress and data.
- */
-export async function isValidSignatureAsync(
-    provider: Provider,
-    data: string,
-    signature: string,
-    signerAddress: string,
-): Promise<boolean> {
-    assert.isWeb3Provider('provider', provider);
-    assert.isHexString('data', data);
-    assert.isHexString('signature', signature);
-    assert.isETHAddressHex('signerAddress', signerAddress);
-    const signatureTypeIndexIfExists = utils.getSignatureTypeIndexIfExists(signature);
-    if (_.isUndefined(signatureTypeIndexIfExists)) {
-        throw new Error(`Unrecognized signatureType in signature: ${signature}`);
-    }
-
-    switch (signatureTypeIndexIfExists) {
-        case SignatureType.Illegal:
-        case SignatureType.Invalid:
-            return false;
-
-        case SignatureType.EIP712: {
-            const ecSignature = parseECSignature(signature);
-            return isValidECSignature(data, ecSignature, signerAddress);
+export const signatureUtils = {
+    /**
+     * Verifies that the provided signature is valid according to the 0x Protocol smart contracts
+     * @param   data          The hex encoded data signed by the supplied signature.
+     * @param   signature     A hex encoded 0x Protocol signature made up of: [TypeSpecificData][SignatureType].
+     *          E.g [vrs][SignatureType.EIP712]
+     * @param   signerAddress The hex encoded address that signed the data, producing the supplied signature.
+     * @return  Whether the signature is valid for the supplied signerAddress and data.
+     */
+    async isValidSignatureAsync(
+        provider: Provider,
+        data: string,
+        signature: string,
+        signerAddress: string,
+    ): Promise<boolean> {
+        assert.isWeb3Provider('provider', provider);
+        assert.isHexString('data', data);
+        assert.isHexString('signature', signature);
+        assert.isETHAddressHex('signerAddress', signerAddress);
+        const signatureTypeIndexIfExists = utils.getSignatureTypeIndexIfExists(signature);
+        if (_.isUndefined(signatureTypeIndexIfExists)) {
+            throw new Error(`Unrecognized signatureType in signature: ${signature}`);
         }
 
-        case SignatureType.EthSign: {
-            const ecSignature = parseECSignature(signature);
-            const prefixedMessageHex = addSignedMessagePrefix(data, SignerType.Default);
-            return isValidECSignature(prefixedMessageHex, ecSignature, signerAddress);
-        }
+        switch (signatureTypeIndexIfExists) {
+            case SignatureType.Illegal:
+            case SignatureType.Invalid:
+                return false;
 
-        case SignatureType.Caller:
-            // HACK: We currently do not "validate" the caller signature type.
-            // It can only be validated during Exchange contract execution.
-            throw new Error('Caller signature type cannot be validated off-chain');
+            case SignatureType.EIP712: {
+                const ecSignature = signatureUtils.parseECSignature(signature);
+                return signatureUtils.isValidECSignature(data, ecSignature, signerAddress);
+            }
 
-        case SignatureType.Wallet: {
-            const isValid = await isValidWalletSignatureAsync(provider, data, signature, signerAddress);
-            return isValid;
-        }
+            case SignatureType.EthSign: {
+                const ecSignature = signatureUtils.parseECSignature(signature);
+                const prefixedMessageHex = signatureUtils.addSignedMessagePrefix(data, SignerType.Default);
+                return signatureUtils.isValidECSignature(prefixedMessageHex, ecSignature, signerAddress);
+            }
 
-        case SignatureType.Validator: {
-            const isValid = await isValidValidatorSignatureAsync(provider, data, signature, signerAddress);
-            return isValid;
-        }
+            case SignatureType.Caller:
+                // HACK: We currently do not "validate" the caller signature type.
+                // It can only be validated during Exchange contract execution.
+                throw new Error('Caller signature type cannot be validated off-chain');
 
-        case SignatureType.PreSigned: {
-            return isValidPresignedSignatureAsync(provider, data, signerAddress);
-        }
+            case SignatureType.Wallet: {
+                const isValid = await signatureUtils.isValidWalletSignatureAsync(
+                    provider,
+                    data,
+                    signature,
+                    signerAddress,
+                );
+                return isValid;
+            }
 
-        case SignatureType.Trezor: {
-            const prefixedMessageHex = addSignedMessagePrefix(data, SignerType.Trezor);
-            const ecSignature = parseECSignature(signature);
-            return isValidECSignature(prefixedMessageHex, ecSignature, signerAddress);
-        }
+            case SignatureType.Validator: {
+                const isValid = await signatureUtils.isValidValidatorSignatureAsync(
+                    provider,
+                    data,
+                    signature,
+                    signerAddress,
+                );
+                return isValid;
+            }
 
-        default:
-            throw new Error(`Unhandled SignatureType: ${signatureTypeIndexIfExists}`);
-    }
-}
+            case SignatureType.PreSigned: {
+                return signatureUtils.isValidPresignedSignatureAsync(provider, data, signerAddress);
+            }
 
-/**
- * Verifies that the provided presigned signature is valid according to the 0x Protocol smart contracts
- * @param   data          The hex encoded data signed by the supplied signature.
- * @param   signature     A hex encoded presigned 0x Protocol signature made up of: [SignatureType.Presigned]
- * @param   signerAddress The hex encoded address that signed the data, producing the supplied signature.
- * @return  Whether the data was preSigned by the supplied signerAddress.
- */
-export async function isValidPresignedSignatureAsync(
-    provider: Provider,
-    data: string,
-    signerAddress: string,
-): Promise<boolean> {
-    assert.isWeb3Provider('provider', provider);
-    assert.isHexString('data', data);
-    assert.isETHAddressHex('signerAddress', signerAddress);
-    const exchangeContract = new ExchangeContract(artifacts.Exchange.compilerOutput.abi, signerAddress, provider);
-    const isValid = await exchangeContract.preSigned.callAsync(data, signerAddress);
-    return isValid;
-}
-
-/**
- * Verifies that the provided wallet signature is valid according to the 0x Protocol smart contracts
- * @param   data          The hex encoded data signed by the supplied signature.
- * @param   signature     A hex encoded presigned 0x Protocol signature made up of: [SignatureType.Presigned]
- * @param   signerAddress The hex encoded address that signed the data, producing the supplied signature.
- * @return  Whether the data was preSigned by the supplied signerAddress.
- */
-export async function isValidWalletSignatureAsync(
-    provider: Provider,
-    data: string,
-    signature: string,
-    signerAddress: string,
-): Promise<boolean> {
-    assert.isWeb3Provider('provider', provider);
-    assert.isHexString('data', data);
-    assert.isHexString('signature', signature);
-    assert.isETHAddressHex('signerAddress', signerAddress);
-    // tslint:disable-next-line:custom-no-magic-numbers
-    const signatureWithoutType = signature.slice(-2);
-    const walletContract = new IWalletContract(artifacts.IWallet.compilerOutput.abi, signerAddress, provider);
-    const isValid = await walletContract.isValidSignature.callAsync(data, signatureWithoutType);
-    return isValid;
-}
-
-/**
- * Verifies that the provided validator signature is valid according to the 0x Protocol smart contracts
- * @param   data          The hex encoded data signed by the supplied signature.
- * @param   signature     A hex encoded presigned 0x Protocol signature made up of: [SignatureType.Presigned]
- * @param   signerAddress The hex encoded address that signed the data, producing the supplied signature.
- * @return  Whether the data was preSigned by the supplied signerAddress.
- */
-export async function isValidValidatorSignatureAsync(
-    provider: Provider,
-    data: string,
-    signature: string,
-    signerAddress: string,
-): Promise<boolean> {
-    assert.isWeb3Provider('provider', provider);
-    assert.isHexString('data', data);
-    assert.isHexString('signature', signature);
-    assert.isETHAddressHex('signerAddress', signerAddress);
-    const validatorSignature = parseValidatorSignature(signature);
-    const exchangeContract = new ExchangeContract(artifacts.Exchange.compilerOutput.abi, signerAddress, provider);
-    const isValidatorApproved = await exchangeContract.allowedValidators.callAsync(
-        signerAddress,
-        validatorSignature.validatorAddress,
-    );
-    if (!isValidatorApproved) {
-        throw new Error(`Validator ${validatorSignature.validatorAddress} was not pre-approved by ${signerAddress}.`);
-    }
+            case SignatureType.Trezor: {
+                const prefixedMessageHex = signatureUtils.addSignedMessagePrefix(data, SignerType.Trezor);
+                const ecSignature = signatureUtils.parseECSignature(signature);
+                return signatureUtils.isValidECSignature(prefixedMessageHex, ecSignature, signerAddress);
+            }
 
-    const validatorContract = new IValidatorContract(artifacts.IValidator.compilerOutput.abi, signerAddress, provider);
-    const isValid = await validatorContract.isValidSignature.callAsync(
-        data,
-        signerAddress,
-        validatorSignature.signature,
-    );
-    return isValid;
-}
-
-/**
- * Checks if the supplied elliptic curve signature corresponds to signing `data` with
- * the private key corresponding to `signerAddress`
- * @param   data          The hex encoded data signed by the supplied signature.
- * @param   signature     An object containing the elliptic curve signature parameters.
- * @param   signerAddress The hex encoded address that signed the data, producing the supplied signature.
- * @return Whether the ECSignature is valid.
- */
-export function isValidECSignature(data: string, signature: ECSignature, signerAddress: string): boolean {
-    assert.isHexString('data', data);
-    assert.doesConformToSchema('signature', signature, schemas.ecSignatureSchema);
-    assert.isETHAddressHex('signerAddress', signerAddress);
-
-    const msgHashBuff = ethUtil.toBuffer(data);
-    try {
-        const pubKey = ethUtil.ecrecover(
-            msgHashBuff,
-            signature.v,
-            ethUtil.toBuffer(signature.r),
-            ethUtil.toBuffer(signature.s),
+            default:
+                throw new Error(`Unhandled SignatureType: ${signatureTypeIndexIfExists}`);
+        }
+    },
+    /**
+     * Verifies that the provided presigned signature is valid according to the 0x Protocol smart contracts
+     * @param   provider      Web3 provider to use for all JSON RPC requests
+     * @param   data          The hex encoded data signed by the supplied signature
+     * @param   signerAddress The hex encoded address that signed the data, producing the supplied signature.
+     * @return  Whether the data was preSigned by the supplied signerAddress
+     */
+    async isValidPresignedSignatureAsync(provider: Provider, data: string, signerAddress: string): Promise<boolean> {
+        assert.isWeb3Provider('provider', provider);
+        assert.isHexString('data', data);
+        assert.isETHAddressHex('signerAddress', signerAddress);
+        const exchangeContract = new ExchangeContract(artifacts.Exchange.compilerOutput.abi, signerAddress, provider);
+        const isValid = await exchangeContract.preSigned.callAsync(data, signerAddress);
+        return isValid;
+    },
+    /**
+     * Verifies that the provided wallet signature is valid according to the 0x Protocol smart contracts
+     * @param   provider      Web3 provider to use for all JSON RPC requests
+     * @param   data          The hex encoded data signed by the supplied signature.
+     * @param   signature     A hex encoded presigned 0x Protocol signature made up of: [SignatureType.Presigned]
+     * @param   signerAddress The hex encoded address that signed the data, producing the supplied signature.
+     * @return  Whether the data was preSigned by the supplied signerAddress.
+     */
+    async isValidWalletSignatureAsync(
+        provider: Provider,
+        data: string,
+        signature: string,
+        signerAddress: string,
+    ): Promise<boolean> {
+        assert.isWeb3Provider('provider', provider);
+        assert.isHexString('data', data);
+        assert.isHexString('signature', signature);
+        assert.isETHAddressHex('signerAddress', signerAddress);
+        // tslint:disable-next-line:custom-no-magic-numbers
+        const signatureWithoutType = signature.slice(-2);
+        const walletContract = new IWalletContract(artifacts.IWallet.compilerOutput.abi, signerAddress, provider);
+        const isValid = await walletContract.isValidSignature.callAsync(data, signatureWithoutType);
+        return isValid;
+    },
+    /**
+     * Verifies that the provided validator signature is valid according to the 0x Protocol smart contracts
+     * @param   provider      Web3 provider to use for all JSON RPC requests
+     * @param   data          The hex encoded data signed by the supplied signature.
+     * @param   signature     A hex encoded presigned 0x Protocol signature made up of: [SignatureType.Presigned]
+     * @param   signerAddress The hex encoded address that signed the data, producing the supplied signature.
+     * @return  Whether the data was preSigned by the supplied signerAddress.
+     */
+    async isValidValidatorSignatureAsync(
+        provider: Provider,
+        data: string,
+        signature: string,
+        signerAddress: string,
+    ): Promise<boolean> {
+        assert.isWeb3Provider('provider', provider);
+        assert.isHexString('data', data);
+        assert.isHexString('signature', signature);
+        assert.isETHAddressHex('signerAddress', signerAddress);
+        const validatorSignature = parseValidatorSignature(signature);
+        const exchangeContract = new ExchangeContract(artifacts.Exchange.compilerOutput.abi, signerAddress, provider);
+        const isValidatorApproved = await exchangeContract.allowedValidators.callAsync(
+            signerAddress,
+            validatorSignature.validatorAddress,
         );
-        const retrievedAddress = ethUtil.bufferToHex(ethUtil.pubToAddress(pubKey));
-        return retrievedAddress === signerAddress;
-    } catch (err) {
-        return false;
-    }
-}
-
-/**
- * Signs an orderHash and returns it's elliptic curve signature and signature type.
- * This method currently supports TestRPC, Geth and Parity above and below V1.6.6
- * @param   orderHash       Hex encoded orderHash to sign.
- * @param   signerAddress   The hex encoded Ethereum address you wish to sign it with. This address
- *          must be available via the Provider supplied to 0x.js.
- * @param   signerType Different signers add/require different prefixes to be prepended to the message being signed.
- *          Since we cannot know ahead of time which signer you are using, you must supply a SignerType.
- * @return  A hex encoded string containing the Elliptic curve signature generated by signing the orderHash and the Signature Type.
- */
-export async function ecSignOrderHashAsync(
-    provider: Provider,
-    orderHash: string,
-    signerAddress: string,
-    signerType: SignerType,
-): Promise<string> {
-    assert.isWeb3Provider('provider', provider);
-    assert.isHexString('orderHash', orderHash);
-    assert.isETHAddressHex('signerAddress', signerAddress);
-    const web3Wrapper = new Web3Wrapper(provider);
-    await assert.isSenderAddressAsync('signerAddress', signerAddress, web3Wrapper);
-    const normalizedSignerAddress = signerAddress.toLowerCase();
+        if (!isValidatorApproved) {
+            throw new Error(
+                `Validator ${validatorSignature.validatorAddress} was not pre-approved by ${signerAddress}.`,
+            );
+        }
 
-    let msgHashHex = orderHash;
-    const prefixedMsgHashHex = addSignedMessagePrefix(orderHash, signerType);
-    // Metamask incorrectly implements eth_sign and does not prefix the message as per the spec
-    // Source: https://github.com/MetaMask/metamask-extension/commit/a9d36860bec424dcee8db043d3e7da6a5ff5672e
-    if (signerType === SignerType.Metamask) {
-        msgHashHex = prefixedMsgHashHex;
-    }
-    const signature = await web3Wrapper.signMessageAsync(normalizedSignerAddress, msgHashHex);
+        const validatorContract = new IValidatorContract(
+            artifacts.IValidator.compilerOutput.abi,
+            signerAddress,
+            provider,
+        );
+        const isValid = await validatorContract.isValidSignature.callAsync(
+            data,
+            signerAddress,
+            validatorSignature.signature,
+        );
+        return isValid;
+    },
+    /**
+     * Checks if the supplied elliptic curve signature corresponds to signing `data` with
+     * the private key corresponding to `signerAddress`
+     * @param   data          The hex encoded data signed by the supplied signature.
+     * @param   signature     An object containing the elliptic curve signature parameters.
+     * @param   signerAddress The hex encoded address that signed the data, producing the supplied signature.
+     * @return Whether the ECSignature is valid.
+     */
+    isValidECSignature(data: string, signature: ECSignature, signerAddress: string): boolean {
+        assert.isHexString('data', data);
+        assert.doesConformToSchema('signature', signature, schemas.ecSignatureSchema);
+        assert.isETHAddressHex('signerAddress', signerAddress);
 
-    // HACK: There is no consensus on whether the signatureHex string should be formatted as
-    // v + r + s OR r + s + v, and different clients (even different versions of the same client)
-    // return the signature params in different orders. In order to support all client implementations,
-    // we parse the signature in both ways, and evaluate if either one is a valid signature.
-    // r + s + v is the most prevalent format from eth_sign, so we attempt this first.
-    // tslint:disable-next-line:custom-no-magic-numbers
-    const validVParamValues = [27, 28];
-    const ecSignatureRSV = parseSignatureHexAsRSV(signature);
-    if (_.includes(validVParamValues, ecSignatureRSV.v)) {
-        const isValidRSVSignature = isValidECSignature(prefixedMsgHashHex, ecSignatureRSV, normalizedSignerAddress);
-        if (isValidRSVSignature) {
-            const convertedSignatureHex = convertECSignatureToSignatureHex(ecSignatureRSV, signerType);
-            return convertedSignatureHex;
+        const msgHashBuff = ethUtil.toBuffer(data);
+        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;
         }
-    }
-    const ecSignatureVRS = parseSignatureHexAsVRS(signature);
-    if (_.includes(validVParamValues, ecSignatureVRS.v)) {
-        const isValidVRSSignature = isValidECSignature(prefixedMsgHashHex, ecSignatureVRS, normalizedSignerAddress);
-        if (isValidVRSSignature) {
-            const convertedSignatureHex = convertECSignatureToSignatureHex(ecSignatureVRS, signerType);
-            return convertedSignatureHex;
+    },
+    /**
+     * Signs an orderHash and returns it's elliptic curve signature and signature type.
+     * This method currently supports TestRPC, Geth and Parity above and below V1.6.6
+     * @param   orderHash       Hex encoded orderHash to sign.
+     * @param   signerAddress   The hex encoded Ethereum address you wish to sign it with. This address
+     *          must be available via the Provider supplied to 0x.js.
+     * @param   signerType Different signers add/require different prefixes to be prepended to the message being signed.
+     *          Since we cannot know ahead of time which signer you are using, you must supply a SignerType.
+     * @return  A hex encoded string containing the Elliptic curve signature generated by signing the orderHash and the Signature Type.
+     */
+    async ecSignOrderHashAsync(
+        provider: Provider,
+        orderHash: string,
+        signerAddress: string,
+        signerType: SignerType,
+    ): Promise<string> {
+        assert.isWeb3Provider('provider', provider);
+        assert.isHexString('orderHash', orderHash);
+        assert.isETHAddressHex('signerAddress', signerAddress);
+        const web3Wrapper = new Web3Wrapper(provider);
+        await assert.isSenderAddressAsync('signerAddress', signerAddress, web3Wrapper);
+        const normalizedSignerAddress = signerAddress.toLowerCase();
+
+        let msgHashHex = orderHash;
+        const prefixedMsgHashHex = signatureUtils.addSignedMessagePrefix(orderHash, signerType);
+        // Metamask incorrectly implements eth_sign and does not prefix the message as per the spec
+        // Source: https://github.com/MetaMask/metamask-extension/commit/a9d36860bec424dcee8db043d3e7da6a5ff5672e
+        if (signerType === SignerType.Metamask) {
+            msgHashHex = prefixedMsgHashHex;
         }
-    }
+        const signature = await web3Wrapper.signMessageAsync(normalizedSignerAddress, msgHashHex);
 
-    throw new Error(OrderError.InvalidSignature);
-}
-/**
- * Combines ECSignature with V,R,S and the relevant signature type for use in 0x protocol
- * @param ecSignature The ECSignature of the signed data
- * @param signerType The SignerType of the signed data
- * @return Hex encoded string of signature (v,r,s) with Signature Type
- */
-export function convertECSignatureToSignatureHex(ecSignature: ECSignature, signerType: SignerType): string {
-    const signatureBuffer = Buffer.concat([
-        ethUtil.toBuffer(ecSignature.v),
-        ethUtil.toBuffer(ecSignature.r),
-        ethUtil.toBuffer(ecSignature.s),
-    ]);
-    const signatureHex = `0x${signatureBuffer.toString('hex')}`;
-    let signatureType;
-    switch (signerType) {
-        case SignerType.Metamask:
-        case SignerType.Ledger:
-        case SignerType.Default: {
-            signatureType = SignatureType.EthSign;
-            break;
+        // HACK: There is no consensus on whether the signatureHex string should be formatted as
+        // v + r + s OR r + s + v, and different clients (even different versions of the same client)
+        // return the signature params in different orders. In order to support all client implementations,
+        // we parse the signature in both ways, and evaluate if either one is a valid signature.
+        // r + s + v is the most prevalent format from eth_sign, so we attempt this first.
+        // tslint:disable-next-line:custom-no-magic-numbers
+        const validVParamValues = [27, 28];
+        const ecSignatureRSV = parseSignatureHexAsRSV(signature);
+        if (_.includes(validVParamValues, ecSignatureRSV.v)) {
+            const isValidRSVSignature = signatureUtils.isValidECSignature(
+                prefixedMsgHashHex,
+                ecSignatureRSV,
+                normalizedSignerAddress,
+            );
+            if (isValidRSVSignature) {
+                const convertedSignatureHex = signatureUtils.convertECSignatureToSignatureHex(
+                    ecSignatureRSV,
+                    signerType,
+                );
+                return convertedSignatureHex;
+            }
         }
-        case SignerType.Trezor: {
-            signatureType = SignatureType.Trezor;
-            break;
+        const ecSignatureVRS = parseSignatureHexAsVRS(signature);
+        if (_.includes(validVParamValues, ecSignatureVRS.v)) {
+            const isValidVRSSignature = signatureUtils.isValidECSignature(
+                prefixedMsgHashHex,
+                ecSignatureVRS,
+                normalizedSignerAddress,
+            );
+            if (isValidVRSSignature) {
+                const convertedSignatureHex = signatureUtils.convertECSignatureToSignatureHex(
+                    ecSignatureVRS,
+                    signerType,
+                );
+                return convertedSignatureHex;
+            }
         }
-        default:
-            throw new Error(`Unrecognized SignerType: ${signerType}`);
-    }
-    const signatureWithType = convertToSignatureWithType(signatureHex, signatureType);
-    return signatureWithType;
-}
-/**
- * Combines the signature proof and the Signature Type.
- * @param signature The hex encoded signature proof
- * @param signatureType The signature type, i.e EthSign, Trezor, Wallet etc.
- * @return Hex encoded string of signature proof with Signature Type
- */
-export function convertToSignatureWithType(signature: string, signatureType: SignatureType): string {
-    const signatureBuffer = Buffer.concat([ethUtil.toBuffer(signature), ethUtil.toBuffer(signatureType)]);
-    const signatureHex = `0x${signatureBuffer.toString('hex')}`;
-    return signatureHex;
-}
-/**
- * Adds the relevant prefix to the message being signed.
- * @param message Message to sign
- * @param signerType The type of message prefix to add for a given SignerType. Different signers expect
- *                          specific message prefixes.
- * @return Prefixed message
- */
-export function addSignedMessagePrefix(message: string, signerType: SignerType = SignerType.Default): string {
-    assert.isString('message', message);
-    assert.doesBelongToStringEnum('signerType', signerType, SignerType);
-    switch (signerType) {
-        case SignerType.Metamask:
-        case SignerType.Ledger:
-        case SignerType.Default: {
-            const msgBuff = ethUtil.toBuffer(message);
-            const prefixedMsgBuff = ethUtil.hashPersonalMessage(msgBuff);
-            const prefixedMsgHex = ethUtil.bufferToHex(prefixedMsgBuff);
-            return prefixedMsgHex;
+
+        throw new Error(OrderError.InvalidSignature);
+    },
+    /**
+     * Combines ECSignature with V,R,S and the relevant signature type for use in 0x protocol
+     * @param ecSignature The ECSignature of the signed data
+     * @param signerType The SignerType of the signed data
+     * @return Hex encoded string of signature (v,r,s) with Signature Type
+     */
+    convertECSignatureToSignatureHex(ecSignature: ECSignature, signerType: SignerType): string {
+        const signatureBuffer = Buffer.concat([
+            ethUtil.toBuffer(ecSignature.v),
+            ethUtil.toBuffer(ecSignature.r),
+            ethUtil.toBuffer(ecSignature.s),
+        ]);
+        const signatureHex = `0x${signatureBuffer.toString('hex')}`;
+        let signatureType;
+        switch (signerType) {
+            case SignerType.Metamask:
+            case SignerType.Ledger:
+            case SignerType.Default: {
+                signatureType = SignatureType.EthSign;
+                break;
+            }
+            case SignerType.Trezor: {
+                signatureType = SignatureType.Trezor;
+                break;
+            }
+            default:
+                throw new Error(`Unrecognized SignerType: ${signerType}`);
         }
-        case SignerType.Trezor: {
-            const msgBuff = ethUtil.toBuffer(message);
-            const prefixedMsgBuff = hashTrezorPersonalMessage(msgBuff);
-            const prefixedMsgHex = ethUtil.bufferToHex(prefixedMsgBuff);
-            return prefixedMsgHex;
+        const signatureWithType = signatureUtils.convertToSignatureWithType(signatureHex, signatureType);
+        return signatureWithType;
+    },
+    /**
+     * Combines the signature proof and the Signature Type.
+     * @param signature The hex encoded signature proof
+     * @param signatureType The signature type, i.e EthSign, Trezor, Wallet etc.
+     * @return Hex encoded string of signature proof with Signature Type
+     */
+    convertToSignatureWithType(signature: string, signatureType: SignatureType): string {
+        const signatureBuffer = Buffer.concat([ethUtil.toBuffer(signature), ethUtil.toBuffer(signatureType)]);
+        const signatureHex = `0x${signatureBuffer.toString('hex')}`;
+        return signatureHex;
+    },
+    /**
+     * Adds the relevant prefix to the message being signed.
+     * @param message Message to sign
+     * @param signerType The type of message prefix to add for a given SignerType. Different signers expect
+     *                          specific message prefixes.
+     * @return Prefixed message
+     */
+    addSignedMessagePrefix(message: string, signerType: SignerType = SignerType.Default): string {
+        assert.isString('message', message);
+        assert.doesBelongToStringEnum('signerType', signerType, SignerType);
+        switch (signerType) {
+            case SignerType.Metamask:
+            case SignerType.Ledger:
+            case SignerType.Default: {
+                const msgBuff = ethUtil.toBuffer(message);
+                const prefixedMsgBuff = ethUtil.hashPersonalMessage(msgBuff);
+                const prefixedMsgHex = ethUtil.bufferToHex(prefixedMsgBuff);
+                return prefixedMsgHex;
+            }
+            case SignerType.Trezor: {
+                const msgBuff = ethUtil.toBuffer(message);
+                const prefixedMsgBuff = hashTrezorPersonalMessage(msgBuff);
+                const prefixedMsgHex = ethUtil.bufferToHex(prefixedMsgBuff);
+                return prefixedMsgHex;
+            }
+            default:
+                throw new Error(`Unrecognized SignerType: ${signerType}`);
         }
-        default:
-            throw new Error(`Unrecognized SignerType: ${signerType}`);
-    }
-}
-
-/**
- * Parse a 0x protocol hex-encoded signature string into it's ECSignature components
- * @param signature A hex encoded ecSignature 0x Protocol signature
- * @return An ECSignature object with r,s,v parameters
- */
-export function parseECSignature(signature: string): ECSignature {
-    assert.isHexString('signature', signature);
-    const ecSignatureTypes = [SignatureType.EthSign, SignatureType.EIP712, SignatureType.Trezor];
-    assert.isOneOfExpectedSignatureTypes(signature, ecSignatureTypes);
+    },
+    /**
+     * Parse a 0x protocol hex-encoded signature string into it's ECSignature components
+     * @param signature A hex encoded ecSignature 0x Protocol signature
+     * @return An ECSignature object with r,s,v parameters
+     */
+    parseECSignature(signature: string): ECSignature {
+        assert.isHexString('signature', signature);
+        const ecSignatureTypes = [SignatureType.EthSign, SignatureType.EIP712, SignatureType.Trezor];
+        assert.isOneOfExpectedSignatureTypes(signature, ecSignatureTypes);
 
-    // tslint:disable-next-line:custom-no-magic-numbers
-    const vrsHex = signature.slice(0, -2);
-    const ecSignature = parseSignatureHexAsVRS(vrsHex);
+        // tslint:disable-next-line:custom-no-magic-numbers
+        const vrsHex = signature.slice(0, -2);
+        const ecSignature = parseSignatureHexAsVRS(vrsHex);
 
-    return ecSignature;
-}
+        return ecSignature;
+    },
+};
 
 function hashTrezorPersonalMessage(message: Buffer): Buffer {
     const prefix = ethUtil.toBuffer('\x19Ethereum Signed Message:\n' + String.fromCharCode(message.byteLength));
diff --git a/packages/order-utils/src/store/balance_and_proxy_allowance_lazy_store.ts b/packages/order-utils/src/store/balance_and_proxy_allowance_lazy_store.ts
index 5a2c1d7ff..8a65178b0 100644
--- a/packages/order-utils/src/store/balance_and_proxy_allowance_lazy_store.ts
+++ b/packages/order-utils/src/store/balance_and_proxy_allowance_lazy_store.ts
@@ -21,11 +21,21 @@ export class BalanceAndProxyAllowanceLazyStore implements AbstractBalanceAndProx
             [userAddress: string]: BigNumber;
         };
     };
+    /**
+     * Instantiates a BalanceAndProxyAllowanceLazyStore
+     * @param balanceAndProxyAllowanceFetcher  Class the implements the AbstractBalanceAndProxyAllowanceFetcher
+     * @return Instance of BalanceAndProxyAllowanceLazyStore
+     */
     constructor(balanceAndProxyAllowanceFetcher: AbstractBalanceAndProxyAllowanceFetcher) {
         this._balanceAndProxyAllowanceFetcher = balanceAndProxyAllowanceFetcher;
         this._balance = {};
         this._proxyAllowance = {};
     }
+    /**
+     * Get a users balance of an asset
+     * @param assetData AssetData of interest
+     * @param userAddress Ethereum address of interest
+     */
     public async getBalanceAsync(assetData: string, userAddress: string): Promise<BigNumber> {
         if (_.isUndefined(this._balance[assetData]) || _.isUndefined(this._balance[assetData][userAddress])) {
             const balance = await this._balanceAndProxyAllowanceFetcher.getBalanceAsync(assetData, userAddress);
@@ -34,12 +44,22 @@ export class BalanceAndProxyAllowanceLazyStore implements AbstractBalanceAndProx
         const cachedBalance = this._balance[assetData][userAddress];
         return cachedBalance;
     }
+    /**
+     * Set the balance of an asset for a user
+     * @param assetData AssetData of interest
+     * @param userAddress Ethereum address of interest
+     */
     public setBalance(assetData: string, userAddress: string, balance: BigNumber): void {
         if (_.isUndefined(this._balance[assetData])) {
             this._balance[assetData] = {};
         }
         this._balance[assetData][userAddress] = balance;
     }
+    /**
+     * Clear the balance of an asset for a user
+     * @param assetData AssetData of interest
+     * @param userAddress Ethereum address of interest
+     */
     public deleteBalance(assetData: string, userAddress: string): void {
         if (!_.isUndefined(this._balance[assetData])) {
             delete this._balance[assetData][userAddress];
@@ -48,6 +68,11 @@ export class BalanceAndProxyAllowanceLazyStore implements AbstractBalanceAndProx
             }
         }
     }
+    /**
+     * Get the 0x asset proxy allowance
+     * @param assetData AssetData of interest
+     * @param userAddress Ethereum address of interest
+     */
     public async getProxyAllowanceAsync(assetData: string, userAddress: string): Promise<BigNumber> {
         if (
             _.isUndefined(this._proxyAllowance[assetData]) ||
@@ -62,12 +87,22 @@ export class BalanceAndProxyAllowanceLazyStore implements AbstractBalanceAndProx
         const cachedProxyAllowance = this._proxyAllowance[assetData][userAddress];
         return cachedProxyAllowance;
     }
+    /**
+     * Set the 0x asset proxy allowance
+     * @param assetData AssetData of interest
+     * @param userAddress Ethereum address of interest
+     */
     public setProxyAllowance(assetData: string, userAddress: string, proxyAllowance: BigNumber): void {
         if (_.isUndefined(this._proxyAllowance[assetData])) {
             this._proxyAllowance[assetData] = {};
         }
         this._proxyAllowance[assetData][userAddress] = proxyAllowance;
     }
+    /**
+     * Clear the 0x asset proxy allowance
+     * @param assetData AssetData of interest
+     * @param userAddress Ethereum address of interest
+     */
     public deleteProxyAllowance(assetData: string, userAddress: string): void {
         if (!_.isUndefined(this._proxyAllowance[assetData])) {
             delete this._proxyAllowance[assetData][userAddress];
@@ -76,6 +111,11 @@ export class BalanceAndProxyAllowanceLazyStore implements AbstractBalanceAndProx
             }
         }
     }
+    /**
+     * Clear all ERC721 0x proxy allowances a user has on all items of a specific ERC721 contract
+     * @param tokenAddress ERc721 token address
+     * @param userAddress Owner Ethereum address
+     */
     public deleteAllERC721ProxyAllowance(tokenAddress: string, userAddress: string): void {
         for (const assetData in this._proxyAllowance) {
             if (this._proxyAllowance.hasOwnProperty(assetData)) {
@@ -90,6 +130,9 @@ export class BalanceAndProxyAllowanceLazyStore implements AbstractBalanceAndProx
             }
         }
     }
+    /**
+     * Delete all balances & allowances
+     */
     public deleteAll(): void {
         this._balance = {};
         this._proxyAllowance = {};
diff --git a/packages/order-utils/src/store/order_filled_cancelled_lazy_store.ts b/packages/order-utils/src/store/order_filled_cancelled_lazy_store.ts
index 336c6d0ba..6155c2064 100644
--- a/packages/order-utils/src/store/order_filled_cancelled_lazy_store.ts
+++ b/packages/order-utils/src/store/order_filled_cancelled_lazy_store.ts
@@ -15,11 +15,21 @@ export class OrderFilledCancelledLazyStore implements AbstractOrderFilledCancell
     private _isCancelled: {
         [orderHash: string]: boolean;
     };
+    /**
+     * Instantiate a OrderFilledCancelledLazyStore
+     * @param orderFilledCancelledFetcher Class instance that implements the AbstractOrderFilledCancelledFetcher
+     * @returns An instance of OrderFilledCancelledLazyStore
+     */
     constructor(orderFilledCancelledFetcher: AbstractOrderFilledCancelledFetcher) {
         this._orderFilledCancelledFetcher = orderFilledCancelledFetcher;
         this._filledTakerAmount = {};
         this._isCancelled = {};
     }
+    /**
+     * Get the filledTakerAssetAmount of an order
+     * @param orderHash OrderHash from order of interest
+     * @return filledTakerAssetAmount
+     */
     public async getFilledTakerAmountAsync(orderHash: string): Promise<BigNumber> {
         if (_.isUndefined(this._filledTakerAmount[orderHash])) {
             const filledTakerAmount = await this._orderFilledCancelledFetcher.getFilledTakerAmountAsync(orderHash);
@@ -28,12 +38,26 @@ export class OrderFilledCancelledLazyStore implements AbstractOrderFilledCancell
         const cachedFilledTakerAmount = this._filledTakerAmount[orderHash];
         return cachedFilledTakerAmount;
     }
+    /**
+     * Set the filledTakerAssetAmount of an order
+     * @param orderHash OrderHash from order of interest
+     * @param filledTakerAmount Desired filledTakerAssetAmount
+     */
     public setFilledTakerAmount(orderHash: string, filledTakerAmount: BigNumber): void {
         this._filledTakerAmount[orderHash] = filledTakerAmount;
     }
+    /**
+     * Clear the filledTakerAssetAmount of an order
+     * @param orderHash OrderHash from order of interest
+     */
     public deleteFilledTakerAmount(orderHash: string): void {
         delete this._filledTakerAmount[orderHash];
     }
+    /**
+     * Check if an order has been cancelled
+     * @param orderHash OrderHash from order of interest
+     * @return Whether the order has been cancelled
+     */
     public async getIsCancelledAsync(orderHash: string): Promise<boolean> {
         if (_.isUndefined(this._isCancelled[orderHash])) {
             const isCancelled = await this._orderFilledCancelledFetcher.isOrderCancelledAsync(orderHash);
@@ -42,22 +66,43 @@ export class OrderFilledCancelledLazyStore implements AbstractOrderFilledCancell
         const cachedIsCancelled = this._isCancelled[orderHash]; // tslint:disable-line:boolean-naming
         return cachedIsCancelled;
     }
+    /**
+     * Set whether an order has been cancelled or not
+     * @param orderHash OrderHash from order of interest
+     * @param isCancelled Whether this order should be cancelled or not
+     */
     public setIsCancelled(orderHash: string, isCancelled: boolean): void {
         this._isCancelled[orderHash] = isCancelled;
     }
+    /**
+     * Clear whether the order has been cancelled if already set
+     * @param orderHash OrderHash from order of interest
+     */
     public deleteIsCancelled(orderHash: string): void {
         delete this._isCancelled[orderHash];
     }
+    /**
+     * Clear all filled/cancelled state
+     */
     public deleteAll(): void {
         this.deleteAllFilled();
         this.deleteAllIsCancelled();
     }
+    /**
+     * Clear all cancelled state
+     */
     public deleteAllIsCancelled(): void {
         this._isCancelled = {};
     }
+    /**
+     * Clear all filled state
+     */
     public deleteAllFilled(): void {
         this._filledTakerAmount = {};
     }
+    /**
+     * Get the ZRX assetData
+     */
     public getZRXAssetData(): string {
         const zrxAssetData = this._orderFilledCancelledFetcher.getZRXAssetData();
         return zrxAssetData;
diff --git a/packages/order-utils/src/types.ts b/packages/order-utils/src/types.ts
index 2e9c79d80..09292e557 100644
--- a/packages/order-utils/src/types.ts
+++ b/packages/order-utils/src/types.ts
@@ -69,3 +69,13 @@ export interface FindFeeOrdersThatCoverFeesForTargetOrdersOpts {
     remainingFillableFeeAmounts?: BigNumber[];
     slippageBufferAmount?: BigNumber;
 }
+
+export interface FeeOrdersAndRemainingFeeAmount<T> {
+    resultFeeOrders: T[];
+    remainingFeeAmount: BigNumber;
+}
+
+export interface OrdersAndRemainingFillAmount<T> {
+    resultOrders: T[];
+    remainingFillAmount: BigNumber;
+}