如何在不使用eval()的情况下编写javascript十六进制初始化器？

function hexInitializer(hexString) {
  var decimalValue = parseInt(hexString, 16);
  return decimalValue;
}

// 示例用法
var hexValue = "FF";
var decimalValue = hexInitializer(hexValue);
console.log(decimalValue); // 输出255

function hexInitializer(hexString) {
  var decimalValue = 0;
  for (var i = 0; i < hexString.length; i++) {
    var char = hexString[i];
    decimalValue = decimalValue << 4;
    if (char >= "0" && char <= "9") {
      decimalValue += char.charCodeAt(0) - "0".charCodeAt(0);
    } else if (char >= "A" && char <= "F") {
      decimalValue += char.charCodeAt(0) - "A".charCodeAt(0) + 10;
    } else if (char >= "a" && char <= "f") {
      decimalValue += char.charCodeAt(0) - "a".charCodeAt(0) + 10;
    }
  }
  return decimalValue;
}

// 示例用法
var hexValue = "FF";
var decimalValue = hexInitializer(hexValue);
console.log(decimalValue); // 输出255