getLiquidityForAssetDataAsync helper method, and fix to assetBuyer to check for eth token in asset pairs

packages/asset-buyer/src/asset_buyer.ts

@@ -227,7 +227,8 @@ export class AssetBuyer {
         assert.isBoolean('shouldForceOrderRefresh', shouldForceOrderRefresh);
 
         const assetPairs = await this.orderProvider.getAvailableMakerAssetDatasAsync(assetData);
-        if (!assetPairs.includes(assetData)) {
+        const etherTokenAssetData = this._getEtherTokenAssetDataOrThrow();
+        if (!assetPairs.includes(etherTokenAssetData)) {
             return {
                 tokensAvailableInBaseUnits: 0,
                 ethValueAvailableInWei: 0,

packages/asset-buyer/test/asset_buyer_test.ts

@@ -24,6 +24,8 @@ const expect = chai.expect;
 const FAKE_SRA_URL = 'https://fakeurl.com';
 const FAKE_ASSET_DATA = '0xf47261b00000000000000000000000001dc4c1cefef38a777b15aa20260a54e584b16c48';
 const TOKEN_DECIMALS = 18;
+const DAI_ASSET_DATA = '0xf47261b000000000000000000000000089d24a6b4ccb1b6faa2625fe562bdd9a23260359"';
+const WETH_ASSET_DATA = '0xf47261b0000000000000000000000000c02aaa39b223fe8d0a0e5c4f27ead9083c756cc2';
 const WETH_DECIMALS = constants.ETHER_TOKEN_DECIMALS;
 
 const baseUnitAmount = (unitAmount: number, decimals = TOKEN_DECIMALS): BigNumber => {
@@ -75,14 +77,26 @@ describe('AssetBuyer', () => {
             });
         });
 
-        it('should return 0s when asset pair not supported', async () => {
-            mockAvailableAssetDatas(mockOrderProvider, FAKE_ASSET_DATA, []);
+        describe('asset pair not supported', () => {
+            it('should return 0s when no asset pair not supported', async () => {
+                mockAvailableAssetDatas(mockOrderProvider, FAKE_ASSET_DATA, []);
 
-            const assetBuyer = new AssetBuyer(mockWeb3Provider.object, mockOrderProvider.object);
-            const liquidityResult = await assetBuyer.getLiquidityForAssetDataAsync(FAKE_ASSET_DATA);
-            expect(liquidityResult).to.deep.equal({
-                tokensAvailableInBaseUnits: 0,
-                ethValueAvailableInWei: 0,
+                const assetBuyer = new AssetBuyer(mockWeb3Provider.object, mockOrderProvider.object);
+                const liquidityResult = await assetBuyer.getLiquidityForAssetDataAsync(FAKE_ASSET_DATA);
+                expect(liquidityResult).to.deep.equal({
+                    tokensAvailableInBaseUnits: 0,
+                    ethValueAvailableInWei: 0,
+                });
+            });
+            it('should return 0s when only other asset pair supported', async () => {
+                mockAvailableAssetDatas(mockOrderProvider, FAKE_ASSET_DATA, [DAI_ASSET_DATA]);
+
+                const assetBuyer = new AssetBuyer(mockWeb3Provider.object, mockOrderProvider.object);
+                const liquidityResult = await assetBuyer.getLiquidityForAssetDataAsync(FAKE_ASSET_DATA);
+                expect(liquidityResult).to.deep.equal({
+                    tokensAvailableInBaseUnits: 0,
+                    ethValueAvailableInWei: 0,
+                });
             });
         });
 
@@ -98,7 +112,7 @@ describe('AssetBuyer', () => {
             });
 
             beforeEach(() => {
-                mockAvailableAssetDatas(mockOrderProvider, FAKE_ASSET_DATA, [FAKE_ASSET_DATA]);
+                mockAvailableAssetDatas(mockOrderProvider, FAKE_ASSET_DATA, [WETH_ASSET_DATA]);
             });
 
             it('should return 0s when no orders available', async () => {

packages/instant/src/index.umd.ts

@@ -1,4 +1,6 @@
+import { AssetBuyer } from '@0x/asset-buyer';
 import { assetDataUtils } from '@0x/order-utils';
+import { Provider } from 'ethereum-types';
 import * as _ from 'lodash';
 import * as React from 'react';
 import * as ReactDOM from 'react-dom';
@@ -12,8 +14,10 @@ import {
 } from './constants';
 import { assetMetaDataMap } from './data/asset_meta_data_map';
 import { ZeroExInstantOverlay, ZeroExInstantOverlayProps } from './index';
+import { Network, OrderSource } from './types';
 import { analytics } from './util/analytics';
 import { assert } from './util/assert';
+import { providerFactory } from './util/provider_factory';
 import { util } from './util/util';
 
 const isInstantRendered = (): boolean => !!document.getElementById(INJECTED_DIV_ID);
@@ -134,6 +138,32 @@ export const hasMetaDataForAssetData = (assetData: string): boolean => {
     return assetMetaDataMap[assetData] !== undefined;
 };
 
+export const getLiquidityForAssetDataAsync = async (
+    assetData: string,
+    orderSource: OrderSource,
+    networkId: Network = Network.Mainnet,
+    provider?: Provider,
+) => {
+    assert.isHexString('assetData', assetData);
+    assert.isValidOrderSource('orderSource', orderSource);
+    assert.isNumber('networkId', networkId);
+
+    if (provider !== undefined) {
+        assert.isWeb3Provider('provider', provider);
+    }
+
+    const bestProvider: Provider = provider || providerFactory.getFallbackNoSigningProvider(networkId);
+
+    const assetBuyerOptions = { networkId };
+
+    const assetBuyer =
+        typeof orderSource === 'string'
+            ? AssetBuyer.getAssetBuyerForStandardRelayerAPIUrl(bestProvider, orderSource, assetBuyerOptions)
+            : AssetBuyer.getAssetBuyerForProvidedOrders(bestProvider, orderSource, assetBuyerOptions);
+
+    return assetBuyer.getLiquidityForAssetDataAsync(assetData);
+};
+
 // Write version info to the exported object for debugging
 export const GIT_SHA = GIT_SHA_FROM_CONSTANT;
 export const NPM_VERSION = NPM_PACKAGE_VERSION;