Y-Combinator in CoffeeScript

y-combinator-generated.js

var Y, factorial;
Y = function(le) {
  return (function(f) {
    return f(f);
  })(function(f) {
    return le(function(x) {
      return f(f)(x);
    });
  });
};

factorial = Y(function(fac) {
  return function(n) {
    if (n <= 2) {
      return n;
    } else {
      return n * fac(n - 1);
    }
  };
});

factorial(5);

y-combinator.coffee

Y = (le) ->
  ((f) -> f f) (f) ->
    le (x) ->
      f(f) x

factorial = Y (fac) -> 
  (n) ->
    if n <= 2 then n else n * fac n-1

factorial 5