Number Base Conversion in JavaScript

Number Conversion in JavaScript

JavaScript provides built-in methods for common base conversions.

parseInt() - String to Number

// Parse with specific base (radix)
parseInt('1010', 2);    // 10 (binary to decimal)
parseInt('FF', 16);     // 255 (hex to decimal)
parseInt('777', 8);     // 511 (octal to decimal)

toString() - Number to String

const num = 255;
num.toString(2);   // "11111111" (binary)
num.toString(8);   // "377" (octal)
num.toString(16);  // "ff" (hex)

Combining for Conversion

// Binary to Hex
function binaryToHex(binary) {
  return parseInt(binary, 2).toString(16);
}
binaryToHex('11111111'); // "ff"
// Any base to any base
function convertBase(value, fromBase, toBase) {
  return parseInt(value, fromBase).toString(toBase);
}
convertBase('ff', 16, 2);  // "11111111"

Handling Large Numbers

For numbers larger than 2^53, use BigInt:

const big = BigInt('0xFFFFFFFFFFFFFFFF');
big.toString(2);
// "1111111111111111111111111111111111111111111111111111111111111111"