TYPESCRIPT

function to find the unique elements from two arrays

var array3 = array1.filter(function(obj) { return array2.indexOf(obj) == -1; });

unique two arrays

const mySet = new Set([1,2])
const additionalSet = [5,2,6]
mySet = new Set([...mySet, ...additionalSet]) // {1,2,5,6}
array = [...new Set([...mySet, ...additionalSet])] // [1,2,5,6]