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'],
// ]