How to check if a path is relative in JavaScript

In this Article we will go through how to check if a path is relative 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 isRelative = path => !/^([a-z]+:)?[\\/]/i.test(path);

isRelative('/foo/bar/baz');         // false
isRelative('C:\\foo\\bar\\baz');    // false
isRelative('foo/bar/baz.txt');      // true
isRelative('foo.md');               // true