Merge pull request #808 from 0xProject/feature/website/better-balance-formatting

Add better balance formatting rules for balances and usd values

2 files changed, 16 insertions, 3 deletions

diff --git a/packages/website/ts/utils/constants.ts b/packages/website/ts/utils/constants.ts
index d3a2aa107..71c0092d2 100644
--- a/packages/website/ts/utils/constants.ts
+++ b/packages/website/ts/utils/constants.ts
@@ -6,7 +6,7 @@ export const constants = {
     ETHER_TOKEN_SYMBOL: 'WETH',
     ZRX_TOKEN_SYMBOL: 'ZRX',
     ETHER_SYMBOL: 'ETH',
-    TOKEN_AMOUNT_DISPLAY_PRECISION: 5,
+    TOKEN_AMOUNT_DISPLAY_PRECISION: 4,
     GENESIS_ORDER_BLOCK_BY_NETWORK_ID: {
         1: 4145578,
         42: 3117574,
@@ -38,6 +38,7 @@ export const constants = {
     UNAVAILABLE_STATUS: 503,
     TAKER_FEE: new BigNumber(0),
     TESTNET_NAME: 'Kovan',
+    NUMERAL_USD_FORMAT: '$0,0.00',
     PROJECT_URL_ETHFINEX: 'https://www.ethfinex.com/',
     PROJECT_URL_AMADEUS: 'http://amadeusrelay.org',
     PROJECT_URL_DDEX: 'https://ddex.io',
diff --git a/packages/website/ts/utils/utils.ts b/packages/website/ts/utils/utils.ts
index 726e1815f..b27c6e48b 100644
--- a/packages/website/ts/utils/utils.ts
+++ b/packages/website/ts/utils/utils.ts
@@ -8,6 +8,8 @@ import * as bowser from 'bowser';
 import deepEqual = require('deep-equal');
 import * as _ from 'lodash';
 import * as moment from 'moment';
+import * as numeral from 'numeral';
+
 import {
     AccountState,
     BlockchainCallErrs,
@@ -380,10 +382,20 @@ export const utils = {
     },
     getFormattedAmount(amount: BigNumber, decimals: number, symbol: string): string {
         const unitAmount = Web3Wrapper.toUnitAmount(amount, decimals);
-        const precision = Math.min(constants.TOKEN_AMOUNT_DISPLAY_PRECISION, unitAmount.decimalPlaces());
-        const formattedAmount = unitAmount.toFixed(precision);
+        // if the unit amount is less than 1, show the natural number of decimal places with a max of 4
+        // if the unit amount is greater than or equal to 1, show only 2 decimal places
+        const precision = unitAmount.lt(1)
+            ? Math.min(constants.TOKEN_AMOUNT_DISPLAY_PRECISION, unitAmount.decimalPlaces())
+            : 2;
+        const format = `0,0.${_.repeat('0', precision)}`;
+        const formattedAmount = numeral(unitAmount).format(format);
         return `${formattedAmount} ${symbol}`;
     },
+    getUsdValueFormattedAmount(amount: BigNumber, decimals: number, price: BigNumber): string {
+        const unitAmount = Web3Wrapper.toUnitAmount(amount, decimals);
+        const value = unitAmount.mul(price);
+        return numeral(value).format(constants.NUMERAL_USD_FORMAT);
+    },
     openUrl(url: string): void {
         window.open(url, '_blank');
     },