How to get union of arrays in JavaScript

In this Article we will go through how to get union of arrays 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 union = (...arr) => [...new Set(arr.flat())];

union([1, 2], [2, 3], [3]);     // [1, 2, 3]