decoder for html by ts

decoder.ts

const decodeHtmlEntity = function (str: string) {
  return str.replace(/&#(\d+);/g, function (match: string, dec: number) {
    return String.fromCharCode(dec)
  })
}

const encodeHtmlEntity = function (str: string) {
  const buf = []
  for (let i = str.length - 1; i >= 0; i--) {
    buf.unshift(['&#', str.charCodeAt(i), ';'].join(''))
  }
  return buf.join('')
}