ArkTS如何实现string和byte数组互转

function stringToByte(str) {
  var bytes = new Array();
  var len,c;
  len = str.length;
  for(var i = 0;i<len;i++) {
    c = str.charCodeAt(i);
    if( c >= 0x010000 && c<= 0x10FFFF) {
      bytes.push(((c>>18) & 0x07) | 0xf0);
      bytes.push(((c>>12) & 0x3F) | 0x80);
      bytes.push(((c>>6) & 0x3f) | 0x80);
      bytes.push((c & 0x3F) | 0x80);
    } else if(c >= 0x000800 && c<= 0x00FFF){
      bytes.push(((c>>12) & 0x07) | 0xf0);
      bytes.push(((c>>6) & 0x3F) | 0x80);
      bytes.push((c & 0x3F) | 0x80);
    } else if(c >= 0x000800 && c<= 0x0007FF) {
      bytes.push(((c>>6) & 0x3F) | 0x80);
      bytes.push((c & 0x3F) | 0x80);
    } else {
      bytes.push(c & 0xFF)
    }
  }
  return bytes;
}

function byteToString(arr) {
  if(typeof arr === 'string') {
    return arr;
  }
  var str = '',
    _arr = arr;
  for(var i = 0; i < _arr.length; i++) {
    var one = _arr[i].toString(2),
      v = one.match(/^1+?(?=0)/);
    if(v && one.length == 8) {
      var bytesLength = v[0].length;
      var store = _arr[i].toString(2).slice(7 - bytesLength);
      for(var st = 1; st < bytesLength; st++) {
        store += _arr[st + i].toString(2).slice(2);
      }
      str += String.fromCharCode(parseInt(store, 2));
      i += bytesLength - 1;
    } else {
      str += String.fromCharCode(_arr[i]);
    }
  }
  return str;
}


@Entry
@Component
struct Index {

  @State context:string="格式转换"


  build() {
    Row() {
      Column() {
        Text(this.context)
          .fontSize(50)
          .fontWeight(FontWeight.Bold).onClick(()=>{


        })
        Text("byte转string")
          .fontSize(50)
          .fontWeight(FontWeight.Bold).onClick(()=>{
          this.context=JSON.stringify(byteToString([200,156]))

        })
        Text("string转byte")
          .fontSize(50)
          .fontWeight(FontWeight.Bold).onClick(()=>{
          this.context=JSON.stringify(stringToByte("坚果"))

        })
      }
      .width('100%')
    }
    .height('100%')
  }
}