Alternative Methods for Converting Decimal to Hexadecimal in JavaScript

Understanding the Basics:

• Decimal: Our everyday number system, using base 10 (digits 0-9).
• Hexadecimal: A number system using base 16 (digits 0-9 and letters A-F).

Conversion Process:

1. Divide by 16:

   • Start with the decimal number.
   • The remainder becomes the least significant digit in the hexadecimal representation.
   • The quotient becomes the new decimal number for the next step.

2. Repeat:

   • Continue dividing the quotient by 16 until the quotient becomes 0.
   • Each remainder becomes a digit in the hexadecimal representation, from least to most significant.

JavaScript Implementation:

JavaScript provides a built-in function called toString() that can be used to convert a number to a string representation in a specified base. To convert a decimal number to hexadecimal, use the toString(16) method:

let decimalNumber = 255;
let hexadecimalNumber = decimalNumber.toString(16);

console.log("Hexadecimal representation:", hexadecimalNumber); // Output: ff

Explanation:

• decimalNumber.toString(16) converts the decimal number 255 to a hexadecimal string.
• The 16 argument specifies that the conversion should be done in base 16.
• The result, ff, is the hexadecimal equivalent of 255.

Additional Notes:

• If the hexadecimal representation has fewer than four digits, you can add leading zeros to make it four digits long (e.g., 00ff instead of ff).
• You can also use the Number.parseInt() function to convert a hexadecimal string back to a decimal number:

let hexadecimalString = "ff";
let decimalNumber = parseInt(hexadecimalString, 16);

console.log("Decimal representation:", decimalNumber); // Output: 255

Converting Decimal to Hexadecimal in JavaScript: Example Codes

Basic Conversion:

let decimalNumber = 255;
let hexadecimalNumber = decimalNumber.toString(16);

console.log("Hexadecimal representation:", hexadecimalNumber); // Output: ff

• Explanation:
  • The 16 argument specifies base 16 for the conversion.

Adding Leading Zeros:

let hexadecimalNumber = decimalNumber.toString(16).padStart(4, '0');

• Explanation:

Custom Function:

function decimalToHex(decimal) {
  return decimal.toString(16).toUpperCase();
}

let hexadecimal = decimalToHex(123);
console.log(hexadecimal); // Output: 7B

• Explanation:
  • Defines a reusable function to convert decimal to hexadecimal.
  • The toUpperCase() method converts the hexadecimal string to uppercase.

Using a Bitwise Operator:

function decimalToHex(decimal) {
  let hexString = "";
  while (decimal > 0) {
    hexString = ((decimal & 15) + "0123456789ABCDEF").charAt(decimal & 15) + hexString;
    decimal >>= 4;
  }
  return hexString;
}

let hexadecimal = decimalToHex(255);
console.log(hexadecimal); // Output: FF

• Explanation:
  • Uses bitwise operations to efficiently convert decimal to hexadecimal.
  • The while loop iterates until the decimal value becomes 0.

Alternative Methods for Converting Decimal to Hexadecimal in JavaScript

While the toString(16) method is a straightforward approach, here are some alternative methods you can consider:

Using a Lookup Table:

• Pre-calculate a lookup table containing the hexadecimal equivalents for decimal numbers from 0 to 15.
• Iteratively divide the decimal number by 16 and use the remainder to index into the lookup table.

const hexLookup = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'];

function decimalToHex(decimal) {
  let hexString = '';
  while (decimal > 0) {
    hexString = hexLookup[decimal % 16] + hexString;
    decimal = Math.floor(decimal / 16);
  }
  return hexString;
}

Leveraging Bitwise Operations:

• Utilize bitwise AND (&) and right shift (>>) operations to extract hexadecimal digits.
• Iterate until the decimal number becomes 0.

function decimalToHex(decimal) {
  let hexString = '';
  while (decimal > 0) {
    hexString = ((decimal & 15) + "0123456789ABCDEF").charAt(decimal & 15) + hexString;
    decimal >>= 4;
  }
  return hexString;
}

Using a Recursive Function:

• Define a recursive function that takes the decimal number as input.
• Base case: If the decimal number is 0, return an empty string.
• Recursive case: Calculate the remainder, convert it to hexadecimal, and append it to the result of the recursive call with the quotient.

function decimalToHex(decimal) {
  if (decimal === 0) {
    return '0';
  }

  const remainder = decimal % 16;
  const quotient = Math.floor(decimal / 16);

  return decimalToHex(quotient) + hexLookup[remainder];
}