return uncommon from two arrays js

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

1let array = [1,2,3,4,5,6,78,9];
2
3function except(array,excluded){
4let newArr,temp,temp1;
5
6      check1=array.filter(function(value) 
7                {
8                  return excluded.indexOf(value) == -1; 
9
10                });
11
12      check2=excluded.filter(function(value) 
13                {
14                  return array.indexOf(value) == -1; 
15
16                });
17
18    output=check1.concat(check2);
19
20
21    return output;
22
23  }
24
25
26except(array,[1,2])
27
28//so the output would be => [ 3, 4, 5, 6, 78, 9 ]