--description--

Objective: Fulfill the user stories below and get all the tests to pass to complete the lab.

User Stories:

1. You should have a function named uniteUnique.
2. The uniteUnique function should accept two or more arrays as arguments.
3. The function should return a new array that contains unique values from the argument arrays, in the order they are first found in the arguments. For example, an input like [1, 2, 4], [2, 3, 5] would have an output of [1, 2, 4, 3, 5].

--hints--

You should have a uniteUnique function.

assert.isFunction(uniteUnique);

uniteUnique([1, 3, 2], [5, 2, 1, 4], [2, 1]) should return [1, 3, 2, 5, 4].

assert.deepEqual(uniteUnique([1, 3, 2], [5, 2, 1, 4], [2, 1]), [1, 3, 2, 5, 4]);

uniteUnique([1, 2, 3], [5, 2, 1]) should return [1, 2, 3, 5].

assert.deepEqual(uniteUnique([1, 2, 3], [5, 2, 1]), [1, 2, 3, 5]);

uniteUnique([1, 2, 3], [5, 2, 1, 4], [2, 1], [6, 7, 8]) should return [1, 2, 3, 5, 4, 6, 7, 8].

assert.deepEqual(uniteUnique([1, 2, 3], [5, 2, 1, 4], [2, 1], [6, 7, 8]), [
  1,
  2,
  3,
  5,
  4,
  6,
  7,
  8
]);

uniteUnique([1, 3, 2], [5, 4], [5, 6]) should return [1, 3, 2, 5, 4, 6].

assert.deepEqual(uniteUnique([1, 3, 2], [5, 4], [5, 6]), [1, 3, 2, 5, 4, 6]);

uniteUnique([1, 3, 2, 3], [5, 2, 1, 4], [2, 1]) should return [1, 3, 2, 5, 4].

assert.deepEqual(uniteUnique([1, 3, 2, 3], [5, 2, 1, 4], [2, 1]), [1, 3, 2, 5, 4]);

--seed--

--seed-contents--

--solutions--

const uniteUnique = (...arrays) => {
  return arrays.reduce((a, b) => {
    return [
      ...a,
      ...b.filter((e, currentIndex) => b.indexOf(e) === currentIndex && a.indexOf(e) === -1)
    ];
  }, []);
};