array.diff.js

// 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 keeping their order.

// 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]

function arrayDiff(a, b) {
    return a.filter((element) => {
        //if the element in the a array is not found in the b array, return it to the filter function and filter it out, leaving just that element that isn't in both arrays
        return b.indexOf(element) < 0;
    })
}
console.log(arrayDiff([1,2], [1]))
console.log(arrayDiff([1,2,3], [1,2]))