javascript combine two arrays without duplicates code example

Example 1: javascript remove duplicate in two arrays

array1 = array1.filter(function(val) {
  return array2.indexOf(val) == -1;
});
// Or, with the availability of ES6:

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

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

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