问将有符号的十进制转换为十六进制，用二的补码编码

EN

 function createToInt(size) {
    if (size < 2) {
        throw new Error('Minimum size is 2');
    }
    else if (size > 64) {
        throw new Error('Maximum size is 64');
    }

    // Determine value range
    const maxValue = (1 << (size - 1)) - 1;
    const minValue = -maxValue - 1;

    return (value) => {
        if (value > maxValue || value < minValue) {
            throw new Error(`Int${size} overflow`);
        }

        if (value < 0) {
            return (1 << size) + value;
        }
        else {
            return value;
        }
    };
}

const toInt8 = createToInt(8);

'0x' + toInt8(-128).toString(16); // -> 0x80
'0x' + toInt8(127).toString(16); // -> 0x7f
'0x' + toInt8(-1).toString(16); // -> 0xff

// Values less then 16 should be padded
'0x' + toInt8(10).toString(16).padStart(2, '0); // -> 0x0a

function DecimalHexTwosComplement(decimal) {
  var size = 8;

  if (decimal >= 0) {
    var hexadecimal = decimal.toString(16);

    while ((hexadecimal.length % size) != 0) {
      hexadecimal = "" + 0 + hexadecimal;
    }

    return hexadecimal;
  } else {
    var hexadecimal = Math.abs(decimal).toString(16);
    while ((hexadecimal.length % size) != 0) {
      hexadecimal = "" + 0 + hexadecimal;
    }

    var output = '';
    for (i = 0; i < hexadecimal.length; i++) {
      output += (0x0F - parseInt(hexadecimal[i], 16)).toString(16);
    }

    output = (0x01 + parseInt(output, 16)).toString(16);
    return output;
  }
}