Symmetric Difference Help

1 
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?

3

Thanks for reply!

I know that this code is limited to certain number of arrays, but I can’t figure out how to handle arguments object to return simple array instead of 2D, 3D array and so on, on each recursion.