Fox Big Decimal

大数操作（加、减、乘、除、格式化）的工具类.

Install

NPM

npm i @fox-js/big-decimal -S

YARN

yarn add @fox-js/big-decimal

使用指南

直接在代码中引入模块即可，模块会自动完成初始化并生效

import '@fox-js/big-decimal'

乘

multiply(x, y)

import { multiply } from '@fox-js/big-decimal'
// 相乘
let n = multiply(336662, 3)
console.info(`multiply:${n}`)

除

divide(x, y, precision = 8)

import { divide } from '@fox-js/big-decimal'
// 相除(最后一位为小数点)
n = divide(36223, 3, 2)
console.info(`divide:${n}`)

加

add(x, y)

import { divide } from '@fox-js/big-decimal'
// 相加
n = add(3533, 15)
console.info(`add:${n}`)

减

subtract(x, y)

import { subtract } from '@fox-js/big-decimal'
// 相减
n = subtract(122223, 22321312)
console.info(`subtract:${n}`)

四舍五入

round(number, precision, roundingMode) 按指定的位数对数值进行四舍五入

import { round } from '@fox-js/big-decimal'

round('123.678', 2) //"123.68"
round('123.657', 1, RoundingModes.DOWN) // "123.6"
round('123.657', 2, RoundingModes.CEILING) // "123.66"

RoundingMode

Round also supports the following rounding modes

• CEILING - Rounding mode to round towards positive infinity.
• DOWN - Rounding mode to round towards zero.
• FLOOR - Rounding mode to round towards negative infinity.
• HALF_DOWN - Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down.
• HALF_EVEN - Rounding mode to round towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor.
• HALF_UP - Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up.
• UNNECESSARY (!Not Implemented!)- Rounding mode to assert that the requested operation has an exact result, hence no rounding is necessary.
• UP - Rounding mode to round away from zero.

floor

floor(number) Returns the whole number nearest but not greater than the input number.

floor(12.8) // "12"
floor(-12.3) // "-13"

ceil

ceil(number) Returns the whole number nearest but not lesser than the input number.

ceil(12.8) // "13"
ceil(-12.3) // "-12"

negate

Returns negation of a given number.

negate('123.678') //  "-123.678"
negate('-1234') //  "1234"

对比

numCompareTo(number1, number2) 比较两个数据，Returns 1, 0 and -1 if number1 > number2, number1 == number2 and number1 < number2 respectively.

compareTo('23.678', '67.34') // value = -1
compareTo('23.678', '23.6780') // value = 0
compareTo('123.678', '67.34') // value = 1

判断数字是否在范围内

inScope(number, min, max)

inScope('1', '1', '5') // false
inScope('3', '1', '10') // true

对数字进行扩展

scaleNumber(value, scale) 如果 scale>0 代表 multiply(value,scale) 如果 scale<0 代表 divide(value, negate(scale))

scaleNumber('100', '5') // 500
scaleNumber('100', '-5') // 20

数据格式化

numberFormat(value, decimalLength = -1, autoPadding = false, digits = 3, separator = ',')

• value 待格式化 value
• decimalLength(小数长度)
• autoPadding(是否自动填充 0)
• digits(分块长度)
• separator(分块隔离符号)

numberFormat('123456') // 123,456
numberFormat('123456.978', 2) // 123,456.97
numberFormat('123456.9', 2, true) // 123,456.90

数据反格式化

unNumberFormat(value)

unNumberFormat('123,456') // 123456