duplicates of 2 arrays javascript code example

Example 1: duplicate numbers in an array javascript

[1, 1, 2, 2, 3].filter((element, index, array) => array.indexOf(element) !== index) // [1, 2]

Example 2: compare two arrays and make sure there are no duplicates js

array1 = array1.filter(val => !array2.includes(val));