BigDecimal

a polyfill for decimal propocal - https://github.com/tc39/proposal-decimal It is implemented on the top of native BigInt. It can be compiled using https://www.npmjs.com/package/babel-plugin-transform-bigint to use JSBI.

Usage:

Installation:

npm install @yaffle/bigdecimal

Type conversion:

BigDecimal.BigDecimal(string)

BigDecimal.BigDecimal(bigint)

BigDecimal.BigDecimal(number) (only integers)

a.toString()

a.toFixed(fractionDigits)

a.toPrecision(precision)

a.toExponential(fractionDigits)

BigDecimal.toBigInt(a) (not in the spec)

BigDecimal.toNumber(a) (not in the spec, only integers)

Arithmetic:

BigDecimal.unaryMinus(a)

BigDecimal.add(a, b[, rounding])

BigDecimal.subtract(a, b[, rounding])

BigDecimal.multiply(a, b[, rounding])

BigDecimal.divide(a, b, rounding)

BigDecimal.round(a, rounding)

Comparison:

BigDecimal.equal(a, b)

BigDecimal.lessThan(a, b)

BigDecimal.greaterThan(a, b)

Math: (not in the spec)

BigDecimal.log(a, rounding)

BigDecimal.exp(a, rounding)

BigDecimal.sin(a, rounding)

BigDecimal.cos(a, rounding)

BigDecimal.atan(a, rounding)

The rounding argument may look like {maximumFractionDigits: 10, roundingMode: "half-even"} or {maximumSignificantDigits: 10, roundingMode: "half-even"}, where the roundingMode can be "floor", or "ceil", or "half-even", or "half-up".

BigFloat

Similar to BigDecimal, but uses base 2.

Example:

import {BigDecimal} from "./node_modules/@yaffle/bigdecimal/BigDecimal.js";

var pi = BigDecimal.multiply(BigDecimal.BigDecimal(4), BigDecimal.atan(BigDecimal.BigDecimal(1), {maximumSignificantDigits: 1000, roundingMode: "half-even"}));

console.log(pi.toString());

Note:

Consider to use only "half-even" rounding mode and rounding to a maximum number of significant digits for floating-point arithmetic, or only "floor" rounding to a maximum number of fraction digits for fixed-point arithmetic. BigFloat may have better performance. Use to round to an integer BigDecimal.round(a, {maximumFractionDigits: 0, roundingMode: "half-even"}).

Similar projects:

1. https://github.com/MikeMcl/decimal.js/
2. https://github.com/uzyn/bigdenary
3. ...