```
function sym(args) {
var arr = Array.prototype.slice.call(arguments);
var diff = [];
// removes duplicate numbers from first two arrays
arr[0] = arr[0].filter((i, pos) => arr[0].indexOf(i) === pos);
arr[1] = arr[1].filter((i, pos) => arr[1].indexOf(i) === pos);
// calculates the difference of two arrays
diff = diff.concat(arr[0].filter(e => arr[1].indexOf(e) === -1));
diff = diff.concat(arr[1].filter(e => arr[0].indexOf(e) === -1));
// removes first two arrays and puts difference in first place
arr.splice(0, 2, diff);
// if there is only one array(diff) as argument, return it
if(!arr[1]) {
return diff.sort((a,b) => a>b);
}
// else run sym() again
sym(diff, arr[1], arr[2], arr[3], arr[4], arr[5]);
}
sym([3, 3, 3, 2, 5], [2, 1, 5, 7], [3, 4, 6, 6], [1, 2, 3], [5, 3, 9, 8], [1]);
```

I tried to write something that looks like recursive function and it works, but when I try to return the final result (sorted diff array) it returns undefined.

If I write diff inside console.log before return it logs diff without mistake… // [ 1, 2, 4, 5, 6, 7, 8, 9 ]

What is the problem?