BigFrac

BigFrac is a typescript rational number library based on BigInt

Install

npm i bigfrac

Alternatively you can import it from a CDN. Example:

import $ from 'https://esm.sh/bigfrac'

Usage

import { BigFrac } from `bigfrac`

const frac1 = new BigFrac('1/3')
const frac2 = new BigFrac('2/4') // 1/2

const frac3 = frac1.add(frac2) // 5/6 

Parsing

BigFrac supports the parsing of different forms of rational numbers representation.

// integer
new BigFrac('1') // = 1/1

// signed
new BigFrac('-1') // = -1/1

// decimal
new BigFrac('1.4') // = 7/5

// repeating decimal
new BigFrac('0.(3)') // = 0.333… = 1/3
new BigFrac('1.9(24)') // = 1.9242424… = 127/66

// exponential
new BigFrac('1.7e3') // = 1.7 × 10³ = 1700/1

// negative exponential
new BigFrac('1.7e-3') // = 0.0017 = 17/10000

// mixed
new BigFrac('-273.6(24)e-3') // = -11287/41250
// fraction

new BigFrac('6/4') // = 3/2

Reference

declare namespace BigFrac {
  // types

  type Input = bigint | number | string | BigFrac
}

declare class BigFrac {
  // properties

  readonly n: bigint
  readonly d: bigint

  // constructors

  constructor(n?: BigFrac.Input = 0n, d?: BigFrac.Input = 1n)
  static from(f?: BigFrac.Input = 0n): BigFrac
  static fromContinuedFraction(cf: BigFrac.Input[]): BigFrac

  // one operand methods

  clone(): BigFrac
  inv(): BigFrac
  abs(): BigFrac
  sign(): 0n | 1n | -1n
  floor(): bigint

  // two operands methods

  mul(f?: BigFrac.Input = 1n): BigFrac
  div(f?: BigFrac.Input = 1n): BigFrac
  add(f?: BigFrac.Input = 0n): BigFrac
  sub(f?: BigFrac.Input = 0n): BigFrac
  pow(p?: bigint = 1n): BigFrac
  mod(f: BigFrac.Input): BigFrac
  mix(f: BigFrac.Input, ratio?: BigFrac.Input = new BigFrac(1n, 2n)): BigFrac
  equal(f: BigFrac.Input): boolean

  // conversion methods

  valueOf(): number
  toString(): string
  toRepeating(base?: number = 10): string
  toDecimal(): string
  toArray(): [numerator: bigint, denominator: bigint]
  toContinuedFraction(): bigint[]
}