Trying to solve symmetric difference using Javascript

Question

I am trying to figure out a solution for symmetric difference using javascript that accomplishes the following objectives:

• accepts an unspecified number of ar

Answer 1

This works for me:

function sym() {
  var args = [].slice.call(arguments);
  
  var getSym = function(arr1, arr2) {
    return arr1.filter(function(each, idx) {
      return arr2.indexOf(each) === -1 && arr1.indexOf(each, idx + 1) === -1;
    }).concat(arr2.filter(function(each, idx) {
      return arr1.indexOf(each) === -1 && arr2.indexOf(each, idx + 1) === -1;
    }));
  };
  
  var result = getSym(args[0], args[1]);
  var len = args.length - 1, i = 2;
  while (--len) {
    result = [].concat(getSym(result, args[i]));
    i++;
  }
  
  return result;
}

console.info(sym([1, 1, 2, 5], [2, 2, 3, 5], [6, 8], [7, 8], [9]));