module.exports = function hex2bin(s) {
  //  discuss at: https://locutus.io/php/hex2bin/
  // original by: Dumitru Uzun (https://duzun.me)
  //   example 1: hex2bin('44696d61')
  //   returns 1: 'Dima'
  //   example 2: hex2bin('00')
  //   returns 2: '\x00'
  //   example 3: hex2bin('2f1q')
  //   returns 3: false

  const ret = []
  let i = 0
  let l

  s += ''

  for (l = s.length; i < l; i += 2) {
    const c = parseInt(s.substr(i, 1), 16)
    const k = parseInt(s.substr(i + 1, 1), 16)
    if (isNaN(c) || isNaN(k)) return false
    ret.push((c << 4) | k)
  }

  return String.fromCharCode.apply(String, ret)
}