Factor in slippage amount in InsufficientAssetLiquidityError error, and show in instant

3 files changed, 23 insertions, 2 deletions

diff --git a/packages/instant/src/constants.ts b/packages/instant/src/constants.ts
index f83eb4ac7..2417c8615 100644
--- a/packages/instant/src/constants.ts
+++ b/packages/instant/src/constants.ts
@@ -16,6 +16,7 @@ export const ONE_SECOND_MS = 1000;
 export const ONE_MINUTE_MS = ONE_SECOND_MS * 60;
 export const GIT_SHA = process.env.GIT_SHA;
 export const NODE_ENV = process.env.NODE_ENV;
+export const SLIPPAGE_PERCENTAGE = 0.2;
 export const NPM_PACKAGE_VERSION = process.env.NPM_PACKAGE_VERSION;
 export const ACCOUNT_UPDATE_INTERVAL_TIME_MS = ONE_SECOND_MS * 5;
 export const BUY_QUOTE_UPDATE_INTERVAL_TIME_MS = ONE_SECOND_MS * 15;
diff --git a/packages/instant/src/util/asset.ts b/packages/instant/src/util/asset.ts
index 13f84ef74..5e83e7e6d 100644
--- a/packages/instant/src/util/asset.ts
+++ b/packages/instant/src/util/asset.ts
@@ -1,7 +1,10 @@
-import { AssetBuyerError } from '@0x/asset-buyer';
+import { AssetBuyerError, InsufficientAssetLiquidityError } from '@0x/asset-buyer';
 import { AssetProxyId, ObjectMap } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import { Web3Wrapper } from '@0x/web3-wrapper';
 import * as _ from 'lodash';
 
+import { BIG_NUMBER_ZERO } from '../constants';
 import { assetDataNetworkMapping } from '../data/asset_data_network_mapping';
 import { Asset, AssetMetaData, ERC20Asset, Network, ZeroExInstantError } from '../types';
 
@@ -110,6 +113,18 @@ export const assetUtils = {
     assetBuyerErrorMessage: (asset: ERC20Asset, error: Error): string | undefined => {
         if (error.message === AssetBuyerError.InsufficientAssetLiquidity) {
             const assetName = assetUtils.bestNameForAsset(asset, 'of this asset');
+            if (error instanceof InsufficientAssetLiquidityError) {
+                const unitAmountAvailableToFill = Web3Wrapper.toUnitAmount(
+                    error.amountAvailableToFill,
+                    asset.metaData.decimals,
+                );
+                const roundedUnitAmountAvailableToFill = unitAmountAvailableToFill.round(2, BigNumber.ROUND_DOWN);
+
+                if (roundedUnitAmountAvailableToFill.greaterThan(BIG_NUMBER_ZERO)) {
+                    return `There are only ${roundedUnitAmountAvailableToFill} ${assetName} available to buy`;
+                }
+            }
+
             return `Not enough ${assetName} available`;
         } else if (error.message === AssetBuyerError.InsufficientZrxLiquidity) {
             return 'Not enough ZRX available';
diff --git a/packages/instant/src/util/buy_quote_updater.ts b/packages/instant/src/util/buy_quote_updater.ts
index 6191c92e3..37974e71c 100644
--- a/packages/instant/src/util/buy_quote_updater.ts
+++ b/packages/instant/src/util/buy_quote_updater.ts
@@ -5,6 +5,7 @@ import * as _ from 'lodash';
 import { Dispatch } from 'redux';
 import { oc } from 'ts-optchain';
 
+import { SLIPPAGE_PERCENTAGE } from '../constants';
 import { Action, actions } from '../redux/actions';
 import { AffiliateInfo, ERC20Asset, QuoteFetchOrigin } from '../types';
 import { analytics } from '../util/analytics';
@@ -33,8 +34,12 @@ export const buyQuoteUpdater = {
         }
         const feePercentage = oc(options.affiliateInfo).feePercentage();
         let newBuyQuote: BuyQuote | undefined;
+        const slippagePercentage = SLIPPAGE_PERCENTAGE;
         try {
-            newBuyQuote = await assetBuyer.getBuyQuoteAsync(asset.assetData, baseUnitValue, { feePercentage });
+            newBuyQuote = await assetBuyer.getBuyQuoteAsync(asset.assetData, baseUnitValue, {
+                feePercentage,
+                slippagePercentage,
+            });
         } catch (error) {
             const errorMessage = assetUtils.assetBuyerErrorMessage(asset, error);