nodejs 十六进制字符串型数据与btye型数据相互转换

/**
 * byte型转换十六进制
 * @param b
 * @returns {string}
 * @constructor
 */
const Bytes2HexString = (b)=> {
  let hexs = "";
  for (let i = 0; i < b.length; i  ) {
    let hex = (b[i]).toString(16);
    if (hex.length === 1) {
      hexs = '0'   hex;
    }
    hexs  = hex.toUpperCase();
  }
  return hexs;
}

/**
 * 十六进制转换btye型
 * @param str
 * @returns {Promise}
 */
const Hexstring2btye = (str)=> {
  let pos = 0;
  let len = str.length;
  if (len % 2 != 0) {
    return null;
  }
  len /= 2;
  let hexA = new Array();
  for (let i = 0; i < len; i  ) {
    let s = str.substr(pos, 2);
    let v = parseInt(s, 16);
    hexA.push(v);
    pos  = 2;
  }
  return hexA;
}