Amy's codewars

Your goal in this kata is to implement a difference function, which subtracts one list from another and returns the result.

It should remove all values from list a, which are present in list b.

Problem 1:

arrayDiff([1,2],[1]) == [2]
If a value is present in b, all of its occurrences must be removed from the other:

arrayDiff([1,2,2,2,3],[2]) == [1,3]

Solution:

Test.describe("Sample tests", function() {
  Test.it("Should pass Sample tests", function() {
    Test.assertDeepEquals(arrayDiff([], [4,5]), [], "a was [], b was [4,5]");
    Test.assertDeepEquals(arrayDiff([3,4], [3]), [4], "a was [3,4], b was [3]");
    Test.assertDeepEquals(arrayDiff([1,8,2], []), [1,8,2], "a was [1,8,2], b was []");
  });
}); 

function arrayDiff(a, b) {
  var filteredArray = a.filter((number) => !b.includes(number));
  return filteredArray;
  
  OR
  
  function array_diff(a, b) {
  return a.filter(function(value)
  {
    return !(b.includes(value))  
  });
}


Problem 2:

// Sum Numbers
function sum (numbers) {
    "use strict";
    var numberTotal= 0;
    
    for(var i = 0; i < numbers.length; i++) {
    numberTotal = numberTotal + numbers[i];
     
    }
     return numberTotal;
  
};