In this example it is described how to specify unique numbers in array through XOR(bitwise).

array_arrayIsUniqueWithXOR.js

let result = 0;
let arr = [1, 2, 5, 4, 6, 1, 2, 5, 4];
for(let i = 0; i <= arr.length; i++){
        result = result ^ arr[i]; 
}
console.log(" this is an unique number " + result);