Convert decimal number to hexadecimal

Numeric values are represented in decimal format by default, when converted to strings. If you want to display them in hexadecimal format, you can use Number.prototype.toString() and pass the base you want to use (16) as an argument.

const decimalToHex = dec => dec.toString(16);

decimalToHex(0); // '0'
decimalToHex(255); // 'ff'

Conversely, the opposite might also be needed. You can use parseInt() to convert a string to a number in a given base. If you don't specify a base, it will default to 10.

const hexToDecimal = hex => parseInt(hex, 16);

hexToDecimal('0'); // 0
hexToDecimal('ff'); // 255