From 9e5e1f568ba71927cec2255bf779322edb6f7d07 Mon Sep 17 00:00:00 2001
From: Steve Klebanoff <steve.klebanoff@gmail.com>
Date: Wed, 12 Dec 2018 14:25:56 -0800
Subject: show as <$0.01 when less than a cent in USD, and also show 1
 significant digit if rounded amount is 0

---
 packages/instant/src/util/format.ts | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

(limited to 'packages/instant/src')

diff --git a/packages/instant/src/util/format.ts b/packages/instant/src/util/format.ts
index e9c432b2f..3aaf9a3a7 100644
--- a/packages/instant/src/util/format.ts
+++ b/packages/instant/src/util/format.ts
@@ -2,7 +2,7 @@ import { BigNumber } from '@0x/utils';
 import { Web3Wrapper } from '@0x/web3-wrapper';
 import * as _ from 'lodash';
 
-import { ETH_DECIMALS } from '../constants';
+import { BIG_NUMBER_ZERO, ETH_DECIMALS } from '../constants';
 
 export const format = {
     ethBaseUnitAmount: (
@@ -25,7 +25,10 @@ export const format = {
             return defaultText;
         }
         const roundedAmount = ethUnitAmount.round(decimalPlaces).toDigits(decimalPlaces);
-        return `${roundedAmount} ETH`;
+        // Sometimes for small ETH amounts (i.e. 0.000045) the amount rounded to 4 decimalPlaces is 0
+        // If that is the case, show to 1 significant digit
+        const displayAmount = roundedAmount.eq(BIG_NUMBER_ZERO) ? ethUnitAmount.toPrecision(1) : roundedAmount;
+        return `${displayAmount} ETH`;
     },
     ethBaseUnitAmountInUsd: (
         ethBaseUnitAmount?: BigNumber,
@@ -48,7 +51,13 @@ export const format = {
         if (_.isUndefined(ethUnitAmount) || _.isUndefined(ethUsdPrice)) {
             return defaultText;
         }
-        return `$${ethUnitAmount.mul(ethUsdPrice).toFixed(decimalPlaces)}`;
+        const rawUsdPrice = ethUnitAmount.mul(ethUsdPrice);
+        const roundedUsdPrice = rawUsdPrice.toFixed(decimalPlaces);
+        if (roundedUsdPrice === '0.00' && rawUsdPrice.gt(BIG_NUMBER_ZERO)) {
+            return '<$0.01';
+        } else {
+            return `$${roundedUsdPrice}`;
+        }
     },
     ethAddress: (address: string): string => {
         return `0x${address.slice(2, 7)}…${address.slice(-5)}`;
-- 
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