gistfile1.txt

function foldl(f, z, xs) {
    return xs.length === 0 ? z : foldl(f, f(z, xs[0], xs.slice(1)));
}

function foldr(f, z, xs) {
    return xs.length === 0 ? z : f(xs[0], foldr(f, z, xs.slice(1)));
}