decimal-format

DecimalFormat

format decimal numbers with a specific pattern

Install

$ npm install decimal-format --save

or use pnpm

$ pnpm add decimal-format --save

Usage

import DecimalFormat from 'decimal-format';

const df = new DecimalFormat('#,##0.0#');
df.format(1234.995);  // 1,235.0
df.format(1234.956);  // 1,234.96

const df1 = new DecimalFormat('#,##0.0#%');
df1.format(0.34995); // 35.0%

const df2 = new DecimalFormat('#,##0.0#‰');
df2.format(0.034993); // 34.99‰

const df3 = new DecimalFormat('￥#,##0.00元');
df3.format(1234.995); // ￥1,235.00元

const df4 = new DecimalFormat('0.00E');
df4.format(1234); // 1.23E3

const df5 = new DecimalFormat('0.00E+');
df5.format(1234); // 1.23E+3

RoundingMode defines the rounding modes of the formatting

import DecimalFormat, { RoundingMode } from 'decimal-format';

const df = new DecimalFormat('#,##0.0#');
df.setRoundingMode(RoundingMode.UP);    // round away from zero
df.format(2.1)      // 3.0
df.format(-2.1)     // -3.0

df.setRoundingMode(RoundingMode.UNNECESSARY) // assert that no rounding is necessary
df.format(2.11)     // 2.11
df.format(2.123)    // throw exception

RoundingMode

Enum	Description
UP	round away from zero
DOWN	round towards zero
CEILING	round towards positive infinity
FLOOR	round towards negative infinity
HALF_UP	round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up
HALF_DOWN	round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down
HALF_EVEN	round towards the "nearest neighbor" unless both neighbors are equidistant, in which case round toward the even neighbor
UNNECESSARY	assert that the requested operation has an exact result, hence no rounding is necessary