export function utf8ByteToUnicodeStr(utf8Bytes) {
  var unicodeStr = "";
  for (var pos = 0; pos < utf8Bytes.length; ) {
    var flag = utf8Bytes[pos];
    var unicode = 0;
    if (flag >>> 7 === 0) {
      unicodeStr += String.fromCharCode(utf8Bytes[pos]);
      pos += 1;
    } else if ((flag & 0xfc) === 0xfc) {
      unicode = (utf8Bytes[pos] & 0x3) << 30;
      unicode |= (utf8Bytes[pos + 1] & 0x3f) << 24;
      unicode |= (utf8Bytes[pos + 2] & 0x3f) << 18;
      unicode |= (utf8Bytes[pos + 3] & 0x3f) << 12;
      unicode |= (utf8Bytes[pos + 4] & 0x3f) << 6;
      unicode |= utf8Bytes[pos + 5] & 0x3f;
      unicodeStr += String.fromCodePoint(unicode);
      pos += 6;
    } else if ((flag & 0xf8) === 0xf8) {
      unicode = (utf8Bytes[pos] & 0x7) << 24;
      unicode |= (utf8Bytes[pos + 1] & 0x3f) << 18;
      unicode |= (utf8Bytes[pos + 2] & 0x3f) << 12;
      unicode |= (utf8Bytes[pos + 3] & 0x3f) << 6;
      unicode |= utf8Bytes[pos + 4] & 0x3f;
      unicodeStr += String.fromCodePoint(unicode);
      pos += 5;
    } else if ((flag & 0xf0) === 0xf0) {
      unicode = (utf8Bytes[pos] & 0xf) << 18;
      unicode |= (utf8Bytes[pos + 1] & 0x3f) << 12;
      unicode |= (utf8Bytes[pos + 2] & 0x3f) << 6;
      unicode |= utf8Bytes[pos + 3] & 0x3f;
      unicodeStr += String.fromCodePoint(unicode);
      pos += 4;
    } else if ((flag & 0xe0) === 0xe0) {
      unicode = (utf8Bytes[pos] & 0x1f) << 12;
      unicode |= (utf8Bytes[pos + 1] & 0x3f) << 6;
      unicode |= utf8Bytes[pos + 2] & 0x3f;
      unicodeStr += String.fromCharCode(unicode);
      pos += 3;
    } else if ((flag & 0xc0) === 0xc0) {
      //110
      unicode = (utf8Bytes[pos] & 0x3f) << 6;
      unicode |= utf8Bytes[pos + 1] & 0x3f;
      unicodeStr += String.fromCharCode(unicode);
      pos += 2;
    } else {
      unicodeStr += String.fromCharCode(utf8Bytes[pos]);
      pos += 1;
    }
  }
  return unicodeStr;
}