Array.diff - K's Dev Blog

Kata

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.

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

If a value is present in b, of its occurrences must be removed from the other:

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

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function arrayDiff(a, b) {
  return a.filter(aItem => !b.includes(aItem));
}

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function array_diff(a, b) {
  return a.filter(function(x) { return b.indexOf(x) == -1; });
}