Add factory method on AssetBuyer for provided orders

1 files changed, 16 insertions, 0 deletions

diff --git a/packages/asset-buyer/src/utils/assert.ts b/packages/asset-buyer/src/utils/assert.ts
index 0085ca41e..edc90608c 100644
--- a/packages/asset-buyer/src/utils/assert.ts
+++ b/packages/asset-buyer/src/utils/assert.ts
@@ -1,5 +1,6 @@
 import { assert as sharedAssert } from '@0xproject/assert';
 import { schemas } from '@0xproject/json-schemas';
+import { SignedOrder } from '@0xproject/types';
 import * as _ from 'lodash';
 
 import { BuyQuote, OrderFetcher, OrderFetcherRequest } from '../types';
@@ -25,4 +26,19 @@ export const assert = {
         sharedAssert.isHexString(`${variableName}.takerAssetData`, orderFetcherRequest.takerAssetData);
         sharedAssert.isNumber(`${variableName}.networkId`, orderFetcherRequest.networkId);
     },
+    areValidProvidedOrders(variableName: string, orders: SignedOrder[]): void {
+        if (orders.length === 0) {
+            return;
+        }
+        const makerAssetData = orders[0].makerAssetData;
+        const takerAssetData = orders[0].takerAssetData;
+        const filteredOrders = _.filter(
+            orders,
+            order => order.makerAssetData === makerAssetData && order.takerAssetData === takerAssetData,
+        );
+        sharedAssert.assert(
+            orders.length === filteredOrders.length,
+            `Expected all orders in ${variableName} to have the same makerAssetData and takerAssetData.`,
+        );
+    },
 };