Tree.findFirst via Alt instance of Option

Tree.findFirst.ts

export const findFirst = <A>(predicate: (a: A) => boolean) => (t: Tree<A>): Option<A> => {
    const ff = findFirst(predicate);
    return t.fold(
        () => none,
        (l, v, r) =>
            ff(l)
                .orElse(() => ff(r))
                .orElse(() => (predicate(v) ? some(v) : none))
    );
};