Merge pull request #479 from 0xProject/bug/website/portal-fill-mixed-decimals

Portal fill with rounding error/mixed decimals

2 files changed, 6 insertions, 3 deletions

diff --git a/packages/website/ts/components/fill_order.tsx b/packages/website/ts/components/fill_order.tsx
index a6144bd6b..ea94e0987 100644
--- a/packages/website/ts/components/fill_order.tsx
+++ b/packages/website/ts/components/fill_order.tsx
@@ -198,11 +198,13 @@ export class FillOrder extends React.Component<FillOrderProps, FillOrderState> {
             symbol: takerToken.symbol,
         };
         const parsedOrderExpiration = new BigNumber(this.state.parsedOrder.signedOrder.expirationUnixTimestampSec);
-        const exchangeRate = orderMakerAmount.div(orderTakerAmount);
 
         let orderReceiveAmount = 0;
         if (!_.isUndefined(this.props.orderFillAmount)) {
-            const orderReceiveAmountBigNumber = exchangeRate.mul(this.props.orderFillAmount);
+            const orderReceiveAmountBigNumber = orderMakerAmount
+                .times(this.props.orderFillAmount)
+                .dividedBy(orderTakerAmount)
+                .floor();
             orderReceiveAmount = this._formatCurrencyAmount(orderReceiveAmountBigNumber, makerToken.decimals);
         }
         const isUserMaker =
diff --git a/packages/website/ts/utils/utils.ts b/packages/website/ts/utils/utils.ts
index 25d7e449b..75597a7e2 100644
--- a/packages/website/ts/utils/utils.ts
+++ b/packages/website/ts/utils/utils.ts
@@ -219,7 +219,8 @@ export const utils = {
             [ExchangeContractErrs.OrderFillAmountZero]: "Order fill amount can't be 0",
             [ExchangeContractErrs.OrderRemainingFillAmountZero]:
                 'This order has already been completely filled or cancelled',
-            [ExchangeContractErrs.OrderFillRoundingError]: 'Rounding error will occur when filling this order',
+            [ExchangeContractErrs.OrderFillRoundingError]:
+                'Rounding error will occur when filling this order. Please try filling a different amount.',
             [ExchangeContractErrs.InsufficientTakerBalance]:
                 'Taker no longer has a sufficient balance to complete this order',
             [ExchangeContractErrs.InsufficientTakerAllowance]: