cross_join

In std/collections.

fn cross_join<T, U, R>(self: Seq<T>, other: Seq<U>, *, into: (T, U) -> R) : Seq<R>

Every pair of an element of the input and an element of other, built by into, in order, with no condition: [1, 2] | cross_join(["a", "b"], into = (x, y) => [x, y]) is [[1, "a"], [1, "b"], [2, "a"], [2, "b"]].