How to check if a string is a hexadecimal number in JavaScript

In this Article we will go through how to check if a string is a hexadecimal number only using single line of code in JavaScript. This is a one-line JavaScript code snippet that uses one of the most popular ES6 features => Arrow Function.

Let's define this short function:

const isHexadecimal = str => /^[A-F0-9]+$/i.test(str);

const isHexadecimal = str => str.split('').every(c => '0123456789ABCDEFabcdef'.indexOf(c) !== -1);

isHexadecimal('123');       // true
isHexadecimal('A1B2C3');    // true
isHexadecimal('#123');      // false