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;}