EN
JavaScript - convert decimal number to bin, oct, hex, etc. (to any base system)
8
points
In this short article, we would like to show how to convert number values in any decimal number to the indicated base system using JavaScript.
Quick solution:
// ONLINE-RUNNER:browser;
var dec = 123; // decinal number
var base = 16; // to base 16 number (to hexadecinal number)
var hex = dec.toString(base);
console.log(hex); // 7b
console.log(hex.toUpperCase()); // 7B
Custom implementation
The below function is able to convert from decimal to:
- bin (binary system),
- oct (octal systems),
- hex (hexal / hexadecimal system),
- any indicated but not greater than 36 (add more characters to the alphabet to get greater base systems).
1. Only positive input integers
// ONLINE-RUNNER:browser;
var ALPHABET = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
function convertBase(dec, base) { // add to ALPHABET more characters to get greater base
if (dec < 0) {
throw new Error('Negative decimal numbers are not supported.');
}
if (base > 1 && base < ALPHABET.length + 1) {
var result = '';
while (true) {
var quotient = Math.floor(dec / base);
var remainder = dec - base * quotient;
result = ALPHABET[remainder] + result;
if (quotient < 1) {
break;
}
dec = quotient;
}
return result;
} else {
throw new Error('Base value should be in range from 2 to ' + ALPHABET.length + '.');
}
}
// Usage example:
// dec base
console.log(convertBase( 0, 2)); // 0 (base 2) <--- bin
console.log(convertBase(123, 2)); // 1111011 (base 2) <--- bin
console.log(convertBase(123, 3)); // 11120 (base 3)
console.log(convertBase(123, 4)); // 1323 (base 4)
console.log(convertBase(123, 5)); // 443 (base 5)
console.log(convertBase(123, 6)); // 323 (base 6)
console.log(convertBase(123, 7)); // 234 (base 7)
console.log(convertBase(123, 8)); // 173 (base 8) <--- oct
console.log(convertBase(123, 10)); // 123 (base 10) <--- dec / identity
console.log(convertBase(123, 16)); // 7B (base 16) <--- hex
console.log(convertBase(123, 32)); // 3R (base 32)
console.log(convertBase(123, 36)); // 3F (base 36)
console.log(convertBase( 36, 36)); // 10 (base 36)
2. Positive and negative input integers
// ONLINE-RUNNER:browser;
var ALPHABET = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
function convertBase(dec, base) { // add to the ALPHABET more characters to get greater base
if (base > 0 && base < ALPHABET.length + 1) {
if (dec === 0) {
return ALPHABET[0] || '';
}
var sign = '';
var result = '';
if (dec < 0) {
dec = -dec;
sign = '-';
}
while (dec > 0) {
var quotient = Math.floor(dec / base);
var remainder = dec - base * quotient;
dec = quotient;
result = ALPHABET[remainder] + result;
}
return sign + result;
} else {
throw new Error('Base value should be in range from 2 to ' + ALPHABET.length + '.');
}
}
// Usage example:
// dec base
console.log(convertBase( 0, 2)); // 0 (base 2) <--- bin
console.log(convertBase(-123, 2)); // -1111011 (base 2) <--- bin
console.log(convertBase( 123, 3)); // 11120 (base 3)
console.log(convertBase(-123, 4)); // -1323 (base 4)
console.log(convertBase( 123, 5)); // 443 (base 5)
console.log(convertBase(-123, 6)); // -323 (base 6)
console.log(convertBase( 123, 7)); // 234 (base 7)
console.log(convertBase(-123, 8)); // -173 (base 8) <--- oct
console.log(convertBase( 123, 10)); // 123 (base 10) <--- dec / identity
console.log(convertBase(-123, 16)); // -7B (base 16) <--- hex
console.log(convertBase( 123, 32)); // 3R (base 32)
console.log(convertBase(-123, 36)); // -3F (base 36)
console.log(convertBase( 36, 36)); // 10 (base 36)