JavaScript RegExp: Get all matches and capture groups

matchAll.js

'use strict'

const { isNull, isStr, isRegExp } = require('./types')

module.exports = matchAll

/**
 * RegExp: Get all matches and capturing groups
 * @param {RegExp} re
 * @param {String} str
 * @returns {Array<Array<String>>}
 */
function matchAll(re, str) {
  if (!isRegExp(re) || !isStr(str))
    throw new Error('matchAll(RegExp, String): received incorrect types')

  const matches = []

  let groups
  while (!isNull((groups = re.exec(str)))) {
    matches.push(Array.from(groups))
  }

  return matches
}

matchAll.test.js

'use strict'

const matchAll = require('./matchAll')

describe('matchAll()', () => {
  it('throws on incorrect regexp', () => {
    const re = {}
    const str = '123'
    expect(() => matchAll(re, str)).toThrowError(/incorrect types/)
  })

  it('throws on incorrect string', () => {
    const re = /[a-z]/
    const str = 123
    expect(() => matchAll(re, str)).toThrowError(/incorrect types/)
  })

  it('returns multiple matches', () => {
    const re = /#{1,6} .+/g
    const str = `asd
      # one
      body 1
      ## two
      body 2
      body 2 more
      ### three
      body 3`

    const result = matchAll(re, str)

    expect(result).toEqual([['# one'], ['## two'], ['### three']])
  })

  it('returns multiple capuring groups', () => {
    const re = /(#{1,6}) (.+)/g
    const str = `asd
      # one
      body 1
      ## two
      body 2
      body 2 more
      ### three
      body 3`

    const result = matchAll(re, str)

    expect(result).toEqual([
      ['# one', '#', 'one'],
      ['## two', '##', 'two'],
      ['### three', '###', 'three']
    ])
  })
})

types.js

'use strict'

module.exports = { isNull, isStr, isRegExp }

function isNull(val) {
  return val === null
}

function isStr(val) {
  return typeof val === 'string'
}

function isArr(val) {
  return Array.isArray(val)
}

function isObj(val) {
  return val === Object(val) && !isArr(val) && !isFunc(val) && !isSymbol(val)
}

function isRegExp(val) {
  return isObj(val) && val instanceof RegExp
}

function isFunc(val) {
  return typeof val === 'function'
}

function isSymbol(val) {
  return typeof val === 'symbol'
}