crossJoin()
The crossJoin method cross joins the collection with the given array or collection, returning all possible permutations:
const collection = collect([1, 2]);
const joined = collection.crossJoin(["a", "b"]);
joined.all();
//=> [
//=> [1, 'a'],
//=> [1, 'b'],
//=> [2, 'a'],
//=> [2, 'b'],
//=> ]