sderosiaux

// http://anler.me/posts/2015-09-17-recursion-aerobics.html
const Y = f => (g => g(g))(g => (f)(arg => (g(g))(arg)));

// define the fact function
const fact = Y(f => n => n === 0 ? 1 : n * f(n-1));

fact(5);
// 120