How to check if a string is an octal number in JavaScript

In this Article we will go through how to check if a string is an octal 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 isOctal = str => /^(0o)?[0-7]+$/i.test(str);