refactored types and market sell operation

packages/asset-buyer/src/quote_consumers/exchange_swap_quote_consumer.ts

@@ -7,13 +7,10 @@ import * as _ from 'lodash';
 import { constants } from '../constants';
 import {
     CalldataInfo,
-    ExchangeMarketBuySmartContractParams,
+    ExchangeSmartContractParams,
-    ExchangeMarketSellSmartContractParams,
-    MarketBuySwapQuote,
-    MarketSellSwapQuote,
     SmartContractParamsInfo,
     SwapQuote,
-    SwapQuoteConsumer,
+    SwapQuoteConsumerBase,
     SwapQuoteConsumerError,
     SwapQuoteConsumerOpts,
     SwapQuoteExecutionOpts,
@@ -23,8 +20,7 @@ import { assert } from '../utils/assert';
 import { swapQuoteConsumerUtils } from '../utils/swap_quote_consumer_utils';
 import { utils } from '../utils/utils';
 
-export class ExchangeSwapQuoteConsumer
+export class ExchangeSwapQuoteConsumer implements SwapQuoteConsumerBase<ExchangeSmartContractParams> {
-    implements SwapQuoteConsumer<ExchangeMarketBuySmartContractParams | ExchangeMarketSellSmartContractParams> {
     public readonly provider: ZeroExProvider;
     public readonly networkId: number;
 
@@ -48,19 +44,18 @@ export class ExchangeSwapQuoteConsumer
     ): Promise<CalldataInfo> {
         assert.isValidSwapQuote('quote', quote);
 
-        const consumableQuote = (quote as any) as (MarketBuySwapQuote | MarketSellSwapQuote);
+        const { to, methodAbi, ethAmount, params } = await this.getSmartContractParamsOrThrowAsync(quote, opts);
-        const smartContractParamsInfo = await this.getSmartContractParamsOrThrowAsync(consumableQuote, opts);
-        const { to, methodAbi, ethAmount } = smartContractParamsInfo;
 
         const abiEncoder = new AbiEncoder.Method(methodAbi);
 
+        const { orders, signatures } = params;
         let args: any[];
-        if (utils.isSwapQuoteMarketBuy(consumableQuote)) {
+        if (params.type === 'marketBuy') {
-            const marketBuyParams = (smartContractParamsInfo.params as any) as ExchangeMarketBuySmartContractParams;
+            const { makerAssetFillAmount } = params;
-            args = [marketBuyParams.orders, marketBuyParams.makerAssetFillAmount, marketBuyParams.signatures];
+            args = [orders, makerAssetFillAmount, signatures];
         } else {
-            const marketSellParams = (smartContractParamsInfo.params as any) as ExchangeMarketSellSmartContractParams;
+            const { takerAssetFillAmount } = params;
-            args = [marketSellParams.orders, marketSellParams.takerAssetFillAmount, marketSellParams.signatures];
+            args = [orders, takerAssetFillAmount, signatures];
         }
         const calldataHexString = abiEncoder.encode(args);
         return {
@@ -73,36 +68,36 @@ export class ExchangeSwapQuoteConsumer
 
     public async getSmartContractParamsOrThrowAsync(
         quote: SwapQuote,
-        opts: Partial<SwapQuoteGetOutputOpts>,
+        _opts: Partial<SwapQuoteGetOutputOpts>,
-    ): Promise<SmartContractParamsInfo<ExchangeMarketBuySmartContractParams | ExchangeMarketSellSmartContractParams>> {
+    ): Promise<SmartContractParamsInfo<ExchangeSmartContractParams>> {
         assert.isValidSwapQuote('quote', quote);
 
-        const consumableQuote = (quote as any) as (MarketBuySwapQuote | MarketSellSwapQuote);
+        const { orders } = quote;
-
-        const { orders } = consumableQuote;
 
         const signatures = _.map(orders, o => o.signature);
 
-        let params: ExchangeMarketBuySmartContractParams | ExchangeMarketSellSmartContractParams;
+        let params: ExchangeSmartContractParams;
         let methodName: string;
 
-        if (utils.isSwapQuoteMarketBuy(consumableQuote)) {
+        if (quote.type === 'marketBuy') {
-            const { makerAssetFillAmount } = consumableQuote;
+            const { makerAssetFillAmount } = quote;
 
             params = {
                 orders,
                 signatures,
                 makerAssetFillAmount,
+                type: 'marketBuy',
             };
 
             methodName = 'marketBuyOrders';
         } else {
-            const { takerAssetFillAmount } = consumableQuote;
+            const { takerAssetFillAmount } = quote;
 
             params = {
                 orders,
                 signatures,
                 takerAssetFillAmount,
+                type: 'marketSell',
             };
 
             methodName = 'marketSellOrders';
@@ -138,16 +133,14 @@ export class ExchangeSwapQuoteConsumer
             assert.isBigNumber('gasPrice', gasPrice);
         }
 
-        const consumableQuote = (quote as any) as (MarketBuySwapQuote | MarketSellSwapQuote);
+        const { orders } = quote;
-
-        const { orders } = consumableQuote;
 
         const finalTakerAddress = await swapQuoteConsumerUtils.getTakerAddressOrThrowAsync(this.provider, opts);
 
         try {
             let txHash: string;
-            if (utils.isSwapQuoteMarketBuy(consumableQuote)) {
+            if (quote.type === 'marketBuy') {
-                const { makerAssetFillAmount } = consumableQuote;
+                const { makerAssetFillAmount } = quote;
                 txHash = await this._contractWrappers.exchange.marketBuyOrdersNoThrowAsync(
                     orders,
                     makerAssetFillAmount,
@@ -159,7 +152,7 @@ export class ExchangeSwapQuoteConsumer
                     },
                 );
             } else {
-                const { takerAssetFillAmount } = consumableQuote;
+                const { takerAssetFillAmount } = quote;
                 txHash = await this._contractWrappers.exchange.marketSellOrdersNoThrowAsync(
                     orders,
                     takerAssetFillAmount,

packages/asset-buyer/src/quote_consumers/forwarder_swap_quote_consumer.ts

@@ -7,15 +7,12 @@ import * as _ from 'lodash';
 import { constants } from '../constants';
 import {
     CalldataInfo,
-    ForwarderMarketBuySmartContractParams,
+    ForwarderSmartContractParams,
-    ForwarderMarketSellSmartContractParams,
     ForwarderSwapQuoteExecutionOpts,
     ForwarderSwapQuoteGetOutputOpts,
-    MarketBuySwapQuote,
-    MarketSellSwapQuote,
     SmartContractParamsInfo,
     SwapQuote,
-    SwapQuoteConsumer,
+    SwapQuoteConsumerBase,
     SwapQuoteConsumerError,
     SwapQuoteConsumerOpts,
 } from '../types';
@@ -25,8 +22,7 @@ import { assetDataUtils } from '../utils/asset_data_utils';
 import { swapQuoteConsumerUtils } from '../utils/swap_quote_consumer_utils';
 import { utils } from '../utils/utils';
 
-export class ForwarderSwapQuoteConsumer
+export class ForwarderSwapQuoteConsumer implements SwapQuoteConsumerBase<ForwarderSmartContractParams> {
-    implements SwapQuoteConsumer<ForwarderMarketBuySmartContractParams | ForwarderMarketSellSmartContractParams> {
     public readonly provider: ZeroExProvider;
     public readonly networkId: number;
 
@@ -55,34 +51,18 @@ export class ForwarderSwapQuoteConsumer
     ): Promise<CalldataInfo> {
         assert.isValidForwarderSwapQuote('quote', quote, this._getEtherTokenAssetDataOrThrow());
 
-        const consumableQuote = (quote as any) as (MarketBuySwapQuote | MarketSellSwapQuote);
+        const { to, methodAbi, ethAmount, params } = await this.getSmartContractParamsOrThrowAsync(quote, opts);
-        const smartContractParamsInfo = await this.getSmartContractParamsOrThrowAsync(consumableQuote, opts);
-        const { to, methodAbi, ethAmount } = smartContractParamsInfo;
 
         const abiEncoder = new AbiEncoder.Method(methodAbi);
 
+        const { orders, signatures, feeOrders, feeSignatures, feePercentage, feeRecipient } = params;
+
         let args: any[];
-        if (utils.isSwapQuoteMarketBuy(consumableQuote)) {
+        if (params.type === 'marketBuy') {
-            const marketBuyParams = (smartContractParamsInfo.params as any) as ForwarderMarketBuySmartContractParams;
+            const { makerAssetFillAmount } = params;
-            args = [
+            args = [orders, makerAssetFillAmount, signatures, feeOrders, feeSignatures, feePercentage, feeRecipient];
-                marketBuyParams.orders,
-                marketBuyParams.makerAssetFillAmount,
-                marketBuyParams.signatures,
-                marketBuyParams.feeOrders,
-                marketBuyParams.feeSignatures,
-                marketBuyParams.feePercentage,
-                marketBuyParams.feeRecipient,
-            ];
         } else {
-            const marketSellParams = (smartContractParamsInfo.params as any) as ForwarderMarketSellSmartContractParams;
+            args = [orders, signatures, feeOrders, feeSignatures, feePercentage, feeRecipient];
-            args = [
-                marketSellParams.orders,
-                marketSellParams.signatures,
-                marketSellParams.feeOrders,
-                marketSellParams.feeSignatures,
-                marketSellParams.feePercentage,
-                marketSellParams.feeRecipient,
-            ];
         }
         const calldataHexString = abiEncoder.encode(args);
         return {
@@ -101,9 +81,7 @@ export class ForwarderSwapQuoteConsumer
     public async getSmartContractParamsOrThrowAsync(
         quote: SwapQuote,
         opts: Partial<ForwarderSwapQuoteGetOutputOpts>,
-    ): Promise<
+    ): Promise<SmartContractParamsInfo<ForwarderSmartContractParams>> {
-        SmartContractParamsInfo<ForwarderMarketBuySmartContractParams | ForwarderMarketSellSmartContractParams>
-    > {
         assert.isValidForwarderSwapQuote('quote', quote, this._getEtherTokenAssetDataOrThrow());
 
         const { ethAmount, feeRecipient, feePercentage: unFormattedFeePercentage } = _.merge(
@@ -118,27 +96,20 @@ export class ForwarderSwapQuoteConsumer
             assert.isBigNumber('ethAmount', ethAmount);
         }
 
-        const swapQuoteWithAffiliateFee = affiliateFeeUtils.getSwapQuoteWithAffiliateFee(
+        const quoteWithAffiliateFee = affiliateFeeUtils.getSwapQuoteWithAffiliateFee(quote, unFormattedFeePercentage);
-            quote,
-            unFormattedFeePercentage,
-        );
 
-        const consumableQuoteWithAffiliateFee = (swapQuoteWithAffiliateFee as any) as (
+        const { orders, feeOrders, worstCaseQuoteInfo } = quoteWithAffiliateFee;
-            | MarketBuySwapQuote
-            | MarketSellSwapQuote);
-
-        const { orders, feeOrders, worstCaseQuoteInfo } = swapQuoteWithAffiliateFee;
 
         const signatures = _.map(orders, o => o.signature);
         const feeSignatures = _.map(feeOrders, o => o.signature);
 
         const feePercentage = utils.numberPercentageToEtherTokenAmountPercentage(unFormattedFeePercentage);
 
-        let params: ForwarderMarketBuySmartContractParams | ForwarderMarketSellSmartContractParams;
+        let params: ForwarderSmartContractParams;
         let methodName: string;
 
-        if (utils.isSwapQuoteMarketBuy(consumableQuoteWithAffiliateFee)) {
+        if (quoteWithAffiliateFee.type === 'marketBuy') {
-            const { makerAssetFillAmount } = consumableQuoteWithAffiliateFee;
+            const { makerAssetFillAmount } = quoteWithAffiliateFee;
 
             params = {
                 orders,
@@ -148,20 +119,19 @@ export class ForwarderSwapQuoteConsumer
                 feeSignatures,
                 feePercentage,
                 feeRecipient,
+                type: 'marketBuy',
             };
 
             methodName = 'marketBuyOrdersWithEth';
         } else {
-            const { takerAssetFillAmount } = consumableQuoteWithAffiliateFee;
-
             params = {
                 orders,
-                takerAssetFillAmount,
                 signatures,
                 feeOrders,
                 feeSignatures,
                 feePercentage,
                 feeRecipient,
+                type: 'marketSell',
             };
             methodName = 'marketSellOrdersWithEth';
         }
@@ -210,20 +180,16 @@ export class ForwarderSwapQuoteConsumer
             assert.isBigNumber('gasPrice', gasPrice);
         }
 
-        const swapQuoteWithAffiliateFee = affiliateFeeUtils.getSwapQuoteWithAffiliateFee(quote, feePercentage);
+        const quoteWithAffiliateFee = affiliateFeeUtils.getSwapQuoteWithAffiliateFee(quote, feePercentage);
 
-        const consumableQuoteWithAffiliateFee = (swapQuoteWithAffiliateFee as any) as (
+        const { orders, feeOrders, worstCaseQuoteInfo } = quoteWithAffiliateFee;
-            | MarketBuySwapQuote
-            | MarketSellSwapQuote);
-
-        const { orders, feeOrders, worstCaseQuoteInfo } = consumableQuoteWithAffiliateFee;
 
         const finalTakerAddress = await swapQuoteConsumerUtils.getTakerAddressOrThrowAsync(this.provider, opts);
 
         try {
             let txHash: string;
-            if (utils.isSwapQuoteMarketBuy(consumableQuoteWithAffiliateFee)) {
+            if (quoteWithAffiliateFee.type === 'marketBuy') {
-                const { makerAssetFillAmount } = consumableQuoteWithAffiliateFee;
+                const { makerAssetFillAmount } = quoteWithAffiliateFee;
                 txHash = await this._contractWrappers.forwarder.marketBuyOrdersWithEthAsync(
                     orders,
                     makerAssetFillAmount,

packages/asset-buyer/src/types.ts

@@ -66,46 +66,48 @@ export interface SmartContractParamsInfo<T> {
     methodAbi: MethodAbi;
 }
 
+export interface SmartContractParamsBase {
+    orders: SignedOrder[];
+    signatures: string[];
+}
+
+export type MarketOperation = 'marketBuy' | 'marketSell';
+
 /**
  * orders: An array of objects conforming to SignedOrder. These orders can be used to cover the requested assetBuyAmount plus slippage.
  * makerAssetFillAmount: The amount of makerAsset to swap for.
  * signatures: An array of signatures that attest that the maker of the orders in fact made the orders.
  */
-export interface ExchangeMarketBuySmartContractParams {
+export interface ExchangeMarketBuySmartContractParams extends SmartContractParamsBase {
-    orders: SignedOrder[];
     makerAssetFillAmount: BigNumber;
-    signatures: string[];
+    type: 'marketBuy';
 }
 
-export interface ExchangeMarketSellSmartContractParams {
+export interface ExchangeMarketSellSmartContractParams extends SmartContractParamsBase {
-    orders: SignedOrder[];
     takerAssetFillAmount: BigNumber;
-    signatures: string[];
+    type: 'marketSell';
 }
 
-/**
+export type ExchangeSmartContractParams = ExchangeMarketBuySmartContractParams | ExchangeMarketSellSmartContractParams;
- * orders: An array of objects conforming to SignedOrder. These orders can be used to cover the requested assetBuyAmount plus slippage.
+
- * makerAssetFillAmount: The amount of makerAsset to swap for.
+export interface ForwarderSmartContractParamsBase {
- * feeOrders: An array of objects conforming to SignedOrder. These orders can be used to cover the fees for the orders param above.
- * signatures: An array of signatures that attest that the maker of the orders in fact made the orders.
- * feeOrders: An array of objects conforming to SignedOrder. These orders can be used to cover the fees for the orders param above.
- * feeSignatures: An array of signatures that attest that the maker of the fee orders in fact made the orders.
- * feePercentage: percentage (up to 5%) of the taker asset paid to feeRecipient
- * feeRecipient: address of the receiver of the feePercentage of taker asset
- */
-export interface ForwarderMarketBuySmartContractParams extends ExchangeMarketBuySmartContractParams {
     feeOrders: SignedOrder[];
     feeSignatures: string[];
     feePercentage: BigNumber;
     feeRecipient: string;
 }
 
-export interface ForwarderMarketSellSmartContractParams extends ExchangeMarketSellSmartContractParams {
+export interface ForwarderMarketBuySmartContractParams
-    feeOrders: SignedOrder[];
+    extends ExchangeMarketBuySmartContractParams,
-    feeSignatures: string[];
+        ForwarderSmartContractParamsBase {}
-    feePercentage: BigNumber;
+
-    feeRecipient: string;
+export interface ForwarderMarketSellSmartContractParams
-}
+    extends Omit<ExchangeMarketSellSmartContractParams, 'takerAssetFillAmount'>,
+        ForwarderSmartContractParamsBase {}
+
+export type ForwarderSmartContractParams =
+    | ForwarderMarketBuySmartContractParams
+    | ForwarderMarketSellSmartContractParams;
 
 /**
  * Interface that varying SwapQuoteConsumers adhere to (exchange consumer, router consumer, forwarder consumer, coordinator consumer)
@@ -113,7 +115,7 @@ export interface ForwarderMarketSellSmartContractParams extends ExchangeMarketSe
  * getSmartContractParamsOrThrow: Get SmartContractParamsInfo to swap for tokens with provided SwapQuote. Throws if invalid SwapQuote is provided.
  * executeSwapQuoteOrThrowAsync: Executes a web3 transaction to swap for tokens with provided SwapQuote. Throws if invalid SwapQuote is provided.
  */
-export interface SwapQuoteConsumer<T> {
+export interface SwapQuoteConsumerBase<T> {
     getCalldataOrThrowAsync(quote: SwapQuote, opts: Partial<SwapQuoteGetOutputOpts>): Promise<CalldataInfo>;
     getSmartContractParamsOrThrowAsync(
         quote: SwapQuote,
@@ -161,6 +163,8 @@ export interface ForwarderSwapQuoteGetOutputOpts extends SwapQuoteGetOutputOpts
  */
 export interface ForwarderSwapQuoteExecutionOpts extends ForwarderSwapQuoteGetOutputOpts, SwapQuoteExecutionOpts {}
 
+export type SwapQuote = MarketBuySwapQuote | MarketSellSwapQuote;
+
 /**
  * takerAssetData: String that represents a specific taker asset (for more info: https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md).
  * makerAssetData: String that represents a specific maker asset (for more info: https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md).
@@ -170,7 +174,7 @@ export interface ForwarderSwapQuoteExecutionOpts extends ForwarderSwapQuoteGetOu
  * bestCaseQuoteInfo: Info about the best case price for the asset.
  * worstCaseQuoteInfo: Info about the worst case price for the asset.
  */
-export interface SwapQuote {
+export interface SwapQuoteBase {
     takerAssetData: string;
     makerAssetData: string;
     orders: SignedOrder[];
@@ -179,22 +183,25 @@ export interface SwapQuote {
     worstCaseQuoteInfo: SwapQuoteInfo;
 }
 
-export interface MarketSellSwapQuote extends SwapQuote {
+export interface MarketSellSwapQuote extends SwapQuoteBase {
     takerAssetFillAmount: BigNumber;
-    bestCaseQuoteInfo: SwapQuoteInfo;
+    type: 'marketSell';
-    worstCaseQuoteInfo: SwapQuoteInfo;
 }
 
-export interface MarketBuySwapQuote extends SwapQuote {
+export interface MarketBuySwapQuote extends SwapQuoteBase {
     makerAssetFillAmount: BigNumber;
-    bestCaseQuoteInfo: SwapQuoteInfo;
+    type: 'marketBuy';
-    worstCaseQuoteInfo: SwapQuoteInfo;
 }
 
-export interface SwapQuoteWithAffiliateFee extends SwapQuote {
+export interface SwapQuoteWithAffiliateFeeBase {
     feePercentage: number;
 }
 
+export interface MarketSellSwapQuoteWithAffiliateFee extends SwapQuoteWithAffiliateFeeBase, MarketSellSwapQuote {}
+
+export interface MarketBuySwapQuoteWithAffiliateFee extends SwapQuoteWithAffiliateFeeBase, MarketBuySwapQuote {}
+
+export type SwapQuoteWithAffiliateFee = MarketBuySwapQuoteWithAffiliateFee | MarketSellSwapQuoteWithAffiliateFee;
 /**
  * assetEthAmount: The amount of eth required to pay for the requested asset.
  * feeEthAmount: The amount of eth required to pay any fee concerned with completing the swap.

packages/asset-buyer/src/utils/assert.ts

@@ -3,8 +3,7 @@ import { schemas } from '@0x/json-schemas';
 import { SignedOrder } from '@0x/types';
 import * as _ from 'lodash';
 
-import { OrderProvider, OrderProviderRequest, SwapQuote, SwapQuoteConsumerError, SwapQuoteInfo } from '../types';
+import { OrderProvider, OrderProviderRequest, SwapQuote, SwapQuoteInfo } from '../types';
-import { utils } from '../utils/utils';
 
 export const assert = {
     ...sharedAssert,
@@ -15,12 +14,10 @@ export const assert = {
         sharedAssert.doesConformToSchema(`${variableName}.feeOrders`, swapQuote.feeOrders, schemas.signedOrdersSchema);
         assert.isValidSwapQuoteInfo(`${variableName}.bestCaseQuoteInfo`, swapQuote.bestCaseQuoteInfo);
         assert.isValidSwapQuoteInfo(`${variableName}.worstCaseQuoteInfo`, swapQuote.worstCaseQuoteInfo);
-        if (utils.isSwapQuoteMarketBuy(swapQuote)) {
+        if (swapQuote.type === 'marketBuy') {
             sharedAssert.isBigNumber(`${variableName}.makerAssetFillAmount`, swapQuote.makerAssetFillAmount);
-        } else if (utils.isSwapQuoteMarketSell(swapQuote)) {
-            sharedAssert.isBigNumber(`${variableName}.takerAssetFillAmount`, swapQuote.takerAssetFillAmount);
         } else {
-            throw new Error(SwapQuoteConsumerError.InvalidMarketSellOrMarketBuySwapQuote);
+            sharedAssert.isBigNumber(`${variableName}.takerAssetFillAmount`, swapQuote.takerAssetFillAmount);
         }
     },
     isValidForwarderSwapQuote(variableName: string, swapQuote: SwapQuote, wethAssetData: string): void {

packages/asset-buyer/src/utils/swap_quote_calculator.ts

@@ -6,8 +6,10 @@ import { constants } from '../constants';
 import { InsufficientAssetLiquidityError } from '../errors';
 import {
     MarketBuySwapQuote,
+    MarketOperation,
     MarketSellSwapQuote,
     OrdersAndFillableAmounts,
+    SwapQuote,
     SwapQuoteInfo,
     SwapQuoterError,
 } from '../types';
@@ -21,6 +23,41 @@ export const swapQuoteCalculator = {
         slippagePercentage: number,
         isMakerAssetZrxToken: boolean,
     ): MarketSellSwapQuote {
+        return calculateSwapQuote(
+            ordersAndFillableAmounts,
+            feeOrdersAndFillableAmounts,
+            takerAssetFillAmount,
+            slippagePercentage,
+            isMakerAssetZrxToken,
+            'marketSell',
+        ) as MarketSellSwapQuote;
+    },
+    calculateMarketBuySwapQuote(
+        ordersAndFillableAmounts: OrdersAndFillableAmounts,
+        feeOrdersAndFillableAmounts: OrdersAndFillableAmounts,
+        makerAssetFillAmount: BigNumber,
+        slippagePercentage: number,
+        isMakerAssetZrxToken: boolean,
+    ): MarketBuySwapQuote {
+        return calculateSwapQuote(
+            ordersAndFillableAmounts,
+            feeOrdersAndFillableAmounts,
+            makerAssetFillAmount,
+            slippagePercentage,
+            isMakerAssetZrxToken,
+            'marketBuy',
+        ) as MarketBuySwapQuote;
+    },
+};
+
+function calculateSwapQuote(
+    ordersAndFillableAmounts: OrdersAndFillableAmounts,
+    feeOrdersAndFillableAmounts: OrdersAndFillableAmounts,
+    assetFillAmount: BigNumber,
+    slippagePercentage: number,
+    isMakerAssetZrxToken: boolean,
+    marketOperation: MarketOperation,
+): SwapQuote {
     const orders = ordersAndFillableAmounts.orders;
     const remainingFillableMakerAssetAmounts = ordersAndFillableAmounts.remainingFillableMakerAssetAmounts;
     const remainingFillableTakerAssetAmounts = remainingFillableMakerAssetAmounts.map(
@@ -30,26 +67,47 @@ export const swapQuoteCalculator = {
     );
     const feeOrders = feeOrdersAndFillableAmounts.orders;
     const remainingFillableFeeAmounts = feeOrdersAndFillableAmounts.remainingFillableMakerAssetAmounts;
-        const slippageBufferAmount = takerAssetFillAmount.multipliedBy(slippagePercentage).integerValue();
+
+    const slippageBufferAmount = assetFillAmount.multipliedBy(slippagePercentage).integerValue();
+
+    let resultOrders: SignedOrder[];
+    let remainingFillAmount: BigNumber;
+    let ordersRemainingFillableMakerAssetAmounts: BigNumber[];
+
+    if (marketOperation === 'marketBuy') {
         // find the orders that cover the desired assetBuyAmount (with slippage)
-        const {
+        ({
+            resultOrders,
+            remainingFillAmount,
+            ordersRemainingFillableMakerAssetAmounts,
+        } = marketUtils.findOrdersThatCoverMakerAssetFillAmount(orders, assetFillAmount, {
+            remainingFillableMakerAssetAmounts,
+            slippageBufferAmount,
+        }));
+    } else {
+        let ordersRemainingFillableTakerAssetAmounts: BigNumber[];
+        // find the orders that cover the desired assetBuyAmount (with slippage)
+        ({
             resultOrders,
             remainingFillAmount,
             ordersRemainingFillableTakerAssetAmounts,
-        } = marketUtils.findOrdersThatCoverTakerAssetFillAmount(orders, takerAssetFillAmount, {
+        } = marketUtils.findOrdersThatCoverTakerAssetFillAmount(orders, assetFillAmount, {
             remainingFillableTakerAssetAmounts,
             slippageBufferAmount,
-        });
+        }));
-        const ordersRemainingFillableMakerAssetAmounts = _.map(
+
+        ordersRemainingFillableMakerAssetAmounts = _.map(
             ordersRemainingFillableTakerAssetAmounts,
             (takerAssetAmount: BigNumber, index: number) => {
                 return orderCalculationUtils.getMakerFillAmount(resultOrders[index], takerAssetAmount);
             },
         );
+    }
+
     // if we do not have enough orders to cover the desired assetBuyAmount, throw
     if (remainingFillAmount.gt(constants.ZERO_AMOUNT)) {
         // We needed the amount they requested to buy, plus the amount for slippage
-            const totalAmountRequested = takerAssetFillAmount.plus(slippageBufferAmount);
+        const totalAmountRequested = assetFillAmount.plus(slippageBufferAmount);
         const amountAbleToFill = totalAmountRequested.minus(remainingFillAmount);
         // multiplierNeededWithSlippage represents what we need to multiply the assetBuyAmount by
         // in order to get the total amount needed considering slippage
@@ -101,151 +159,81 @@ export const swapQuoteCalculator = {
         orders: resultFeeOrders,
         remainingFillableMakerAssetAmounts: feeOrdersRemainingFillableMakerAssetAmounts,
     };
-        const bestCaseQuoteInfo = calculateMarketSellQuoteInfo(
+
+    const bestCaseQuoteInfo = calculateQuoteInfo(
         trimmedOrdersAndFillableAmounts,
         trimmedFeeOrdersAndFillableAmounts,
-            takerAssetFillAmount,
+        assetFillAmount,
         isMakerAssetZrxToken,
+        marketOperation,
     );
     // in order to calculate the maxRate, reverse the ordersAndFillableAmounts such that they are sorted from worst rate to best rate
-        const worstCaseQuoteInfo = calculateMarketSellQuoteInfo(
+    const worstCaseQuoteInfo = calculateQuoteInfo(
         reverseOrdersAndFillableAmounts(trimmedOrdersAndFillableAmounts),
         reverseOrdersAndFillableAmounts(trimmedFeeOrdersAndFillableAmounts),
-            takerAssetFillAmount,
+        assetFillAmount,
         isMakerAssetZrxToken,
+        marketOperation,
     );
 
-        return {
+    const quoteBase = {
         takerAssetData,
         makerAssetData,
-            takerAssetFillAmount,
         orders: resultOrders,
         feeOrders: resultFeeOrders,
         bestCaseQuoteInfo,
         worstCaseQuoteInfo,
     };
-    },
-    calculateMarketBuySwapQuote(
-        ordersAndFillableAmounts: OrdersAndFillableAmounts,
-        feeOrdersAndFillableAmounts: OrdersAndFillableAmounts,
-        makerAssetFillAmount: BigNumber,
-        slippagePercentage: number,
-        isMakerAssetZrxToken: boolean,
-    ): MarketBuySwapQuote {
-        const orders = ordersAndFillableAmounts.orders;
-        const remainingFillableMakerAssetAmounts = ordersAndFillableAmounts.remainingFillableMakerAssetAmounts;
-        const feeOrders = feeOrdersAndFillableAmounts.orders;
-        const remainingFillableFeeAmounts = feeOrdersAndFillableAmounts.remainingFillableMakerAssetAmounts;
-        const slippageBufferAmount = makerAssetFillAmount.multipliedBy(slippagePercentage).integerValue();
-        // find the orders that cover the desired assetBuyAmount (with slippage)
-        const {
-            resultOrders,
-            remainingFillAmount,
-            ordersRemainingFillableMakerAssetAmounts,
-        } = marketUtils.findOrdersThatCoverMakerAssetFillAmount(orders, makerAssetFillAmount, {
-            remainingFillableMakerAssetAmounts,
-            slippageBufferAmount,
-        });
-        // if we do not have enough orders to cover the desired assetBuyAmount, throw
-        if (remainingFillAmount.gt(constants.ZERO_AMOUNT)) {
-            // We needed the amount they requested to buy, plus the amount for slippage
-            const totalAmountRequested = makerAssetFillAmount.plus(slippageBufferAmount);
-            const amountAbleToFill = totalAmountRequested.minus(remainingFillAmount);
-            // multiplierNeededWithSlippage represents what we need to multiply the assetBuyAmount by
-            // in order to get the total amount needed considering slippage
-            // i.e. if slippagePercent was 0.2 (20%), multiplierNeededWithSlippage would be 1.2
-            const multiplierNeededWithSlippage = new BigNumber(1).plus(slippagePercentage);
-            // Given amountAvailableToFillConsideringSlippage * multiplierNeededWithSlippage = amountAbleToFill
-            // We divide amountUnableToFill by multiplierNeededWithSlippage to determine amountAvailableToFillConsideringSlippage
-            const amountAvailableToFillConsideringSlippage = amountAbleToFill
-                .div(multiplierNeededWithSlippage)
-                .integerValue(BigNumber.ROUND_FLOOR);
-
-            throw new InsufficientAssetLiquidityError(amountAvailableToFillConsideringSlippage);
-        }
-        // if we are not buying ZRX:
-        // given the orders calculated above, find the fee-orders that cover the desired assetBuyAmount (with slippage)
-        // TODO(bmillman): optimization
-        // update this logic to find the minimum amount of feeOrders to cover the worst case as opposed to
-        // finding order that cover all fees, this will help with estimating ETH and minimizing gas usage
-        let resultFeeOrders = [] as SignedOrder[];
-        let feeOrdersRemainingFillableMakerAssetAmounts = [] as BigNumber[];
-        if (!isMakerAssetZrxToken) {
-            const feeOrdersAndRemainingFeeAmount = marketUtils.findFeeOrdersThatCoverFeesForTargetOrders(
-                resultOrders,
-                feeOrders,
-                {
-                    remainingFillableMakerAssetAmounts: ordersRemainingFillableMakerAssetAmounts,
-                    remainingFillableFeeAmounts,
-                },
-            );
-            // if we do not have enough feeOrders to cover the fees, throw
-            if (feeOrdersAndRemainingFeeAmount.remainingFeeAmount.gt(constants.ZERO_AMOUNT)) {
-                throw new Error(SwapQuoterError.InsufficientZrxLiquidity);
-            }
-            resultFeeOrders = feeOrdersAndRemainingFeeAmount.resultFeeOrders;
-            feeOrdersRemainingFillableMakerAssetAmounts =
-                feeOrdersAndRemainingFeeAmount.feeOrdersRemainingFillableMakerAssetAmounts;
-        }
-
-        // assetData information for the result
-        const takerAssetData = orders[0].takerAssetData;
-        const makerAssetData = orders[0].makerAssetData;
-
-        // compile the resulting trimmed set of orders for makerAsset and feeOrders that are needed for assetBuyAmount
-        const trimmedOrdersAndFillableAmounts: OrdersAndFillableAmounts = {
-            orders: resultOrders,
-            remainingFillableMakerAssetAmounts: ordersRemainingFillableMakerAssetAmounts,
-        };
-        const trimmedFeeOrdersAndFillableAmounts: OrdersAndFillableAmounts = {
-            orders: resultFeeOrders,
-            remainingFillableMakerAssetAmounts: feeOrdersRemainingFillableMakerAssetAmounts,
-        };
-        const bestCaseQuoteInfo = calculateMarketBuyQuoteInfo(
-            trimmedOrdersAndFillableAmounts,
-            trimmedFeeOrdersAndFillableAmounts,
-            makerAssetFillAmount,
-            isMakerAssetZrxToken,
-        );
-        // in order to calculate the maxRate, reverse the ordersAndFillableAmounts such that they are sorted from worst rate to best rate
-        const worstCaseQuoteInfo = calculateMarketBuyQuoteInfo(
-            reverseOrdersAndFillableAmounts(trimmedOrdersAndFillableAmounts),
-            reverseOrdersAndFillableAmounts(trimmedFeeOrdersAndFillableAmounts),
-            makerAssetFillAmount,
-            isMakerAssetZrxToken,
-        );
 
+    if (marketOperation === 'marketBuy') {
         return {
-            takerAssetData,
+            ...quoteBase,
-            makerAssetData,
+            type: 'marketBuy',
-            makerAssetFillAmount,
+            makerAssetFillAmount: assetFillAmount,
-            orders: resultOrders,
-            feeOrders: resultFeeOrders,
-            bestCaseQuoteInfo,
-            worstCaseQuoteInfo,
         };
-    },
+    } else {
+        return {
+            ...quoteBase,
+            type: 'marketSell',
+            takerAssetFillAmount: assetFillAmount,
         };
+    }
+}
 
-function calculateMarketBuyQuoteInfo(
+function calculateQuoteInfo(
     ordersAndFillableAmounts: OrdersAndFillableAmounts,
     feeOrdersAndFillableAmounts: OrdersAndFillableAmounts,
-    makerTokenAmount: BigNumber,
+    tokenAmount: BigNumber,
     isMakerAssetZrxToken: boolean,
+    marketOperation: MarketOperation,
 ): SwapQuoteInfo {
     // find the total eth and zrx needed to buy assetAmount from the resultOrders from left to right
-    let takerTokenAmount = constants.ZERO_AMOUNT;
+    let makerTokenAmount = marketOperation === 'marketBuy' ? tokenAmount : constants.ZERO_AMOUNT;
+    let takerTokenAmount = marketOperation === 'marketSell' ? tokenAmount : constants.ZERO_AMOUNT;
     let zrxTakerTokenAmount = constants.ZERO_AMOUNT;
+
     if (isMakerAssetZrxToken) {
+        if (marketOperation === 'marketBuy') {
             takerTokenAmount = findTakerTokenAmountNeededToBuyZrx(ordersAndFillableAmounts, makerTokenAmount);
         } else {
-        // find eth and zrx amounts needed to buy
+            makerTokenAmount = findZrxTokenAmountFromSellingTakerTokenAmount(
-        const takerTokenAndZrxAmountToBuyAsset = findTakerTokenAndZrxAmountNeededToBuyAsset(
                 ordersAndFillableAmounts,
-            makerTokenAmount,
+                takerTokenAmount,
             );
-        takerTokenAmount = takerTokenAndZrxAmountToBuyAsset[0];
+        }
-        const zrxAmountToBuyAsset = takerTokenAndZrxAmountToBuyAsset[1];
+    } else {
+        const findTokenAndZrxAmount =
+            marketOperation === 'marketBuy'
+                ? findTakerTokenAndZrxAmountNeededToBuyAsset
+                : findMakerTokenAmountReceivedAndZrxAmountNeededToSellAsset;
+        // find eth and zrx amounts needed to buy
+        const tokenAndZrxAmountToBuyAsset = findTokenAndZrxAmount(ordersAndFillableAmounts, makerTokenAmount);
+        if (marketOperation === 'marketBuy') {
+            takerTokenAmount = tokenAndZrxAmountToBuyAsset[0];
+        } else {
+            makerTokenAmount = tokenAndZrxAmountToBuyAsset[0];
+        }
+        const zrxAmountToBuyAsset = tokenAndZrxAmountToBuyAsset[1];
         // find eth amount needed to buy zrx
         zrxTakerTokenAmount = findTakerTokenAmountNeededToBuyZrx(feeOrdersAndFillableAmounts, zrxAmountToBuyAsset);
     }
@@ -261,42 +249,6 @@ function calculateMarketBuyQuoteInfo(
         totalTakerTokenAmount,
     };
 }
-
-function calculateMarketSellQuoteInfo(
-    ordersAndFillableAmounts: OrdersAndFillableAmounts,
-    feeOrdersAndFillableAmounts: OrdersAndFillableAmounts,
-    takerTokenAmount: BigNumber,
-    isMakerAssetZrxToken: boolean,
-): SwapQuoteInfo {
-    // find the total eth and zrx needed to buy assetAmount from the resultOrders from left to right
-    let makerTokenAmount = constants.ZERO_AMOUNT;
-    let zrxTakerTokenAmount = constants.ZERO_AMOUNT;
-    if (isMakerAssetZrxToken) {
-        makerTokenAmount = findZrxTokenAmountFromSellingTakerTokenAmount(ordersAndFillableAmounts, takerTokenAmount);
-    } else {
-        // find eth and zrx amounts needed to buy
-        const takerTokenAndZrxAmountToBuyAsset = findMakerTokenAmountReceivedAndZrxAmountNeededToSellAsset(
-            ordersAndFillableAmounts,
-            takerTokenAmount,
-        );
-        makerTokenAmount = takerTokenAndZrxAmountToBuyAsset[0];
-        const zrxAmountToSellAsset = takerTokenAndZrxAmountToBuyAsset[1];
-        // find eth amount needed to buy zrx
-        zrxTakerTokenAmount = findTakerTokenAmountNeededToBuyZrx(feeOrdersAndFillableAmounts, zrxAmountToSellAsset);
-    }
-
-    const feeTakerTokenAmount = zrxTakerTokenAmount;
-
-    // eth amount needed in total is the sum of the amount needed for the asset and the amount needed for fees
-    const totalTakerTokenAmount = takerTokenAmount.plus(feeTakerTokenAmount);
-    return {
-        makerTokenAmount,
-        takerTokenAmount,
-        feeTakerTokenAmount,
-        totalTakerTokenAmount,
-    };
-}
-
 // given an OrdersAndFillableAmounts, reverse the orders and remainingFillableMakerAssetAmounts properties
 function reverseOrdersAndFillableAmounts(ordersAndFillableAmounts: OrdersAndFillableAmounts): OrdersAndFillableAmounts {
     const ordersCopy = _.clone(ordersAndFillableAmounts.orders);

packages/asset-buyer/src/utils/utils.ts

@@ -4,7 +4,6 @@ import { AbiDefinition, ContractAbi, MethodAbi } from 'ethereum-types';
 import * as _ from 'lodash';
 
 import { constants } from '../constants';
-import { MarketBuySwapQuote, MarketSellSwapQuote, SwapQuote } from '../types';
 
 // tslint:disable:no-unnecessary-type-assertion
 export const utils = {
@@ -26,10 +25,4 @@ export const utils = {
             },
         ) as MethodAbi | undefined;
     },
-    isSwapQuoteMarketBuy(quote: SwapQuote): quote is MarketBuySwapQuote {
-        return (quote as MarketSellSwapQuote).takerAssetFillAmount !== undefined;
-    },
-    isSwapQuoteMarketSell(quote: SwapQuote): quote is MarketSellSwapQuote {
-        return (quote as MarketBuySwapQuote).makerAssetFillAmount !== undefined;
-    },
 };

packages/asset-buyer/test/utils/swap_quote.ts

@@ -3,7 +3,7 @@ import { SignedOrder } from '@0x/types';
 import { BigNumber } from '@0x/utils';
 import * as _ from 'lodash';
 
-import { MarketBuySwapQuote, MarketSellSwapQuote } from '../../src';
+import { MarketOperation, SwapQuote } from '../../src/types';
 
 const ZERO_BIG_NUMBER = new BigNumber(0);
 
@@ -25,11 +25,12 @@ export const getSignedOrdersWithNoFees = (
     );
 };
 
-export const getFullyFillableMarketBuySwapQuoteWithNoFees = (
+export const getFullyFillableSwapQuoteWithNoFees = (
     makerAssetData: string,
     takerAssetData: string,
     orders: SignedOrder[],
-): MarketBuySwapQuote => {
+    operation: MarketOperation,
+): SwapQuote => {
     const makerAssetFillAmount = _.reduce(
         orders,
         (a: BigNumber, c: SignedOrder) => a.plus(c.makerAssetAmount),
@@ -47,46 +48,26 @@ export const getFullyFillableMarketBuySwapQuoteWithNoFees = (
         totalTakerTokenAmount,
     };
 
-    return {
+    const quoteBase = {
         makerAssetData,
         takerAssetData,
         orders,
         feeOrders: [],
+        bestCaseQuoteInfo: quoteInfo,
+        worstCaseQuoteInfo: quoteInfo,
+    };
+
+    if (operation === 'marketBuy') {
+        return {
+            ...quoteBase,
+            type: 'marketBuy',
             makerAssetFillAmount,
-        bestCaseQuoteInfo: quoteInfo,
-        worstCaseQuoteInfo: quoteInfo,
         };
-};
+    } else {
-
-export const getFullyFillableMarketSellSwapQuoteWithNoFees = (
-    makerAssetData: string,
-    takerAssetData: string,
-    orders: SignedOrder[],
-): MarketSellSwapQuote => {
-    const makerAssetFillAmount = _.reduce(
-        orders,
-        (a: BigNumber, c: SignedOrder) => a.plus(c.makerAssetAmount),
-        ZERO_BIG_NUMBER,
-    );
-    const totalTakerTokenAmount = _.reduce(
-        orders,
-        (a: BigNumber, c: SignedOrder) => a.plus(c.takerAssetAmount),
-        ZERO_BIG_NUMBER,
-    );
-    const quoteInfo = {
-        makerTokenAmount: makerAssetFillAmount,
-        takerTokenAmount: totalTakerTokenAmount,
-        feeTakerTokenAmount: ZERO_BIG_NUMBER,
-        totalTakerTokenAmount,
-    };
-
         return {
-        makerAssetData,
+            ...quoteBase,
-        takerAssetData,
+            type: 'marketSell',
-        orders,
-        feeOrders: [],
             takerAssetFillAmount: totalTakerTokenAmount,
-        bestCaseQuoteInfo: quoteInfo,
-        worstCaseQuoteInfo: quoteInfo,
         };
+    }
 };

packages/order-utils/src/market_utils.ts

@@ -10,6 +10,7 @@ import {
     FindFeeOrdersThatCoverFeesForTargetOrdersOpts,
     FindOrdersThatCoverMakerAssetFillAmountOpts,
     FindOrdersThatCoverTakerAssetFillAmountOpts,
+    MarketOperation,
     OrdersAndRemainingMakerFillAmount,
     OrdersAndRemainingTakerFillAmount,
 } from './types';
@@ -20,60 +21,12 @@ export const marketUtils = {
         takerAssetFillAmount: BigNumber,
         opts?: FindOrdersThatCoverTakerAssetFillAmountOpts,
     ): OrdersAndRemainingTakerFillAmount<T> {
-        assert.doesConformToSchema('orders', orders, schemas.ordersSchema);
+        return findOrdersThatCoverAssetFillAmount(
-        assert.isValidBaseUnitAmount('takerAssetFillAmount', takerAssetFillAmount);
-        // try to get remainingFillableTakerAssetAmounts from opts, if it's not there, use takerAssetAmount values from orders
-        const remainingFillableTakerAssetAmounts = _.get(
-            opts,
-            'remainingFillableTakerAssetAmounts',
-            _.map(orders, order => order.takerAssetAmount),
-        ) as BigNumber[];
-        _.forEach(remainingFillableTakerAssetAmounts, (amount, index) =>
-            assert.isValidBaseUnitAmount(`remainingFillableTakerAssetAmount[${index}]`, amount),
-        );
-        assert.assert(
-            orders.length === remainingFillableTakerAssetAmounts.length,
-            'Expected orders.length to equal opts.remainingFillableMakerAssetAmounts.length',
-        );
-        // try to get slippageBufferAmount from opts, if it's not there, default to 0
-        const slippageBufferAmount = _.get(opts, 'slippageBufferAmount', constants.ZERO_AMOUNT) as BigNumber;
-        assert.isValidBaseUnitAmount('opts.slippageBufferAmount', slippageBufferAmount);
-        // calculate total amount of makerAsset needed to be filled
-        const totalFillAmount = takerAssetFillAmount.plus(slippageBufferAmount);
-        // iterate through the orders input from left to right until we have enough makerAsset to fill totalFillAmount
-        const result = _.reduce(
             orders,
-            ({ resultOrders, remainingFillAmount, ordersRemainingFillableTakerAssetAmounts }, order, index) => {
+            takerAssetFillAmount,
-                if (remainingFillAmount.isLessThanOrEqualTo(constants.ZERO_AMOUNT)) {
+            'marketSell',
-                    return {
+            opts,
-                        resultOrders,
+        ) as OrdersAndRemainingTakerFillAmount<T>;
-                        remainingFillAmount: constants.ZERO_AMOUNT,
-                        ordersRemainingFillableTakerAssetAmounts,
-                    };
-                } else {
-                    const takerAssetAmountAvailable = remainingFillableTakerAssetAmounts[index];
-                    const shouldIncludeOrder = takerAssetAmountAvailable.gt(constants.ZERO_AMOUNT);
-                    // if there is no makerAssetAmountAvailable do not append order to resultOrders
-                    // if we have exceeded the total amount we want to fill set remainingFillAmount to 0
-                    return {
-                        resultOrders: shouldIncludeOrder ? _.concat(resultOrders, order) : resultOrders,
-                        ordersRemainingFillableTakerAssetAmounts: shouldIncludeOrder
-                            ? _.concat(ordersRemainingFillableTakerAssetAmounts, takerAssetAmountAvailable)
-                            : ordersRemainingFillableTakerAssetAmounts,
-                        remainingFillAmount: BigNumber.max(
-                            constants.ZERO_AMOUNT,
-                            remainingFillAmount.minus(takerAssetAmountAvailable),
-                        ),
-                    };
-                }
-            },
-            {
-                resultOrders: [] as T[],
-                remainingFillAmount: totalFillAmount,
-                ordersRemainingFillableTakerAssetAmounts: [] as BigNumber[],
-            },
-        );
-        return result;
     },
     /**
      * Takes an array of orders and returns a subset of those orders that has enough makerAssetAmount
@@ -90,60 +43,12 @@ export const marketUtils = {
         makerAssetFillAmount: BigNumber,
         opts?: FindOrdersThatCoverMakerAssetFillAmountOpts,
     ): OrdersAndRemainingMakerFillAmount<T> {
-        assert.doesConformToSchema('orders', orders, schemas.ordersSchema);
+        return findOrdersThatCoverAssetFillAmount(
-        assert.isValidBaseUnitAmount('makerAssetFillAmount', makerAssetFillAmount);
-        // try to get remainingFillableMakerAssetAmounts from opts, if it's not there, use makerAssetAmount values from orders
-        const remainingFillableMakerAssetAmounts = _.get(
-            opts,
-            'remainingFillableMakerAssetAmounts',
-            _.map(orders, order => order.makerAssetAmount),
-        ) as BigNumber[];
-        _.forEach(remainingFillableMakerAssetAmounts, (amount, index) =>
-            assert.isValidBaseUnitAmount(`remainingFillableMakerAssetAmount[${index}]`, amount),
-        );
-        assert.assert(
-            orders.length === remainingFillableMakerAssetAmounts.length,
-            'Expected orders.length to equal opts.remainingFillableMakerAssetAmounts.length',
-        );
-        // try to get slippageBufferAmount from opts, if it's not there, default to 0
-        const slippageBufferAmount = _.get(opts, 'slippageBufferAmount', constants.ZERO_AMOUNT) as BigNumber;
-        assert.isValidBaseUnitAmount('opts.slippageBufferAmount', slippageBufferAmount);
-        // calculate total amount of makerAsset needed to be filled
-        const totalFillAmount = makerAssetFillAmount.plus(slippageBufferAmount);
-        // iterate through the orders input from left to right until we have enough makerAsset to fill totalFillAmount
-        const result = _.reduce(
             orders,
-            ({ resultOrders, remainingFillAmount, ordersRemainingFillableMakerAssetAmounts }, order, index) => {
+            makerAssetFillAmount,
-                if (remainingFillAmount.isLessThanOrEqualTo(constants.ZERO_AMOUNT)) {
+            'marketBuy',
-                    return {
+            opts,
-                        resultOrders,
+        ) as OrdersAndRemainingMakerFillAmount<T>;
-                        remainingFillAmount: constants.ZERO_AMOUNT,
-                        ordersRemainingFillableMakerAssetAmounts,
-                    };
-                } else {
-                    const makerAssetAmountAvailable = remainingFillableMakerAssetAmounts[index];
-                    const shouldIncludeOrder = makerAssetAmountAvailable.gt(constants.ZERO_AMOUNT);
-                    // if there is no makerAssetAmountAvailable do not append order to resultOrders
-                    // if we have exceeded the total amount we want to fill set remainingFillAmount to 0
-                    return {
-                        resultOrders: shouldIncludeOrder ? _.concat(resultOrders, order) : resultOrders,
-                        ordersRemainingFillableMakerAssetAmounts: shouldIncludeOrder
-                            ? _.concat(ordersRemainingFillableMakerAssetAmounts, makerAssetAmountAvailable)
-                            : ordersRemainingFillableMakerAssetAmounts,
-                        remainingFillAmount: BigNumber.max(
-                            constants.ZERO_AMOUNT,
-                            remainingFillAmount.minus(makerAssetAmountAvailable),
-                        ),
-                    };
-                }
-            },
-            {
-                resultOrders: [] as T[],
-                remainingFillAmount: totalFillAmount,
-                ordersRemainingFillableMakerAssetAmounts: [] as BigNumber[],
-            },
-        );
-        return result;
     },
     /**
      * Takes an array of orders and an array of feeOrders. Returns a subset of the feeOrders that has enough ZRX
@@ -222,3 +127,82 @@ export const marketUtils = {
         // https://github.com/0xProject/0x-protocol-specification/blob/master/v2/forwarding-contract-specification.md#over-buying-zrx
     },
 };
+
+function findOrdersThatCoverAssetFillAmount<T extends Order>(
+    orders: T[],
+    assetFillAmount: BigNumber,
+    operation: MarketOperation,
+    opts?: FindOrdersThatCoverTakerAssetFillAmountOpts,
+): OrdersAndRemainingTakerFillAmount<T> | OrdersAndRemainingMakerFillAmount<T> {
+    const variablePrefix = operation === 'marketBuy' ? 'maker' : 'taker';
+    assert.doesConformToSchema('orders', orders, schemas.ordersSchema);
+    assert.isValidBaseUnitAmount(`${variablePrefix}AssetFillAmount}`, assetFillAmount);
+    // try to get remainingFillableTakerAssetAmounts from opts, if it's not there, use takerAssetAmount values from orders
+    const remainingFillableAssetAmounts = _.get(
+        opts,
+        `remainingFillable${variablePrefix}AssetAmounts`,
+        _.map(orders, order => (operation === 'marketBuy' ? order.makerAssetAmount : order.takerAssetAmount)),
+    ) as BigNumber[];
+    _.forEach(remainingFillableAssetAmounts, (amount, index) =>
+        assert.isValidBaseUnitAmount(`remainingFillable${variablePrefix}AssetAmount[${index}]`, amount),
+    );
+    assert.assert(
+        orders.length === remainingFillableAssetAmounts.length,
+        `Expected orders.length to equal opts.remainingFillable${variablePrefix}AssetAmounts.length`,
+    );
+    // try to get slippageBufferAmount from opts, if it's not there, default to 0
+    const slippageBufferAmount = _.get(opts, 'slippageBufferAmount', constants.ZERO_AMOUNT) as BigNumber;
+    assert.isValidBaseUnitAmount('opts.slippageBufferAmount', slippageBufferAmount);
+    // calculate total amount of asset needed to be filled
+    const totalFillAmount = assetFillAmount.plus(slippageBufferAmount);
+    // iterate through the orders input from left to right until we have enough makerAsset to fill totalFillAmount
+    const result = _.reduce(
+        orders,
+        ({ resultOrders, remainingFillAmount, ordersRemainingFillableAssetAmounts }, order, index) => {
+            if (remainingFillAmount.isLessThanOrEqualTo(constants.ZERO_AMOUNT)) {
+                return {
+                    resultOrders,
+                    remainingFillAmount: constants.ZERO_AMOUNT,
+                    ordersRemainingFillableAssetAmounts,
+                };
+            } else {
+                const assetAmountAvailable = remainingFillableAssetAmounts[index];
+                const shouldIncludeOrder = assetAmountAvailable.gt(constants.ZERO_AMOUNT);
+                // if there is no assetAmountAvailable do not append order to resultOrders
+                // if we have exceeded the total amount we want to fill set remainingFillAmount to 0
+                return {
+                    resultOrders: shouldIncludeOrder ? _.concat(resultOrders, order) : resultOrders,
+                    ordersRemainingFillableAssetAmounts: shouldIncludeOrder
+                        ? _.concat(ordersRemainingFillableAssetAmounts, assetAmountAvailable)
+                        : ordersRemainingFillableAssetAmounts,
+                    remainingFillAmount: BigNumber.max(
+                        constants.ZERO_AMOUNT,
+                        remainingFillAmount.minus(assetAmountAvailable),
+                    ),
+                };
+            }
+        },
+        {
+            resultOrders: [] as T[],
+            remainingFillAmount: totalFillAmount,
+            ordersRemainingFillableAssetAmounts: [] as BigNumber[],
+        },
+    );
+
+    const {
+        ordersRemainingFillableAssetAmounts: resultOrdersRemainingFillableAssetAmounts,
+        ...ordersAndRemainingFillAmount
+    } = result;
+
+    if (operation === 'marketBuy') {
+        return {
+            ...ordersAndRemainingFillAmount,
+            ordersRemainingFillableMakerAssetAmounts: resultOrdersRemainingFillableAssetAmounts,
+        };
+    } else {
+        return {
+            ...ordersAndRemainingFillAmount,
+            ordersRemainingFillableMakerAssetAmounts: resultOrdersRemainingFillableAssetAmounts,
+        };
+    }
+}

packages/order-utils/src/types.ts

@@ -49,6 +49,8 @@ export interface FindOrdersThatCoverTakerAssetFillAmountOpts {
     slippageBufferAmount?: BigNumber;
 }
 
+export type MarketOperation = 'marketSell' | 'marketBuy';
+
 /**
  * remainingFillableMakerAssetAmount: An array of BigNumbers corresponding to the `orders` parameter.
  * You can use `OrderStateUtils` `@0x/order-utils` to perform blockchain lookups for these values.