console.log("Define: Y")

function Y(bindFn) { 

  console.log("Y");

  return function () {

    console.log("Y-Annon");

    return bindFn(Y(bindFn)).apply(null, arguments);

  };

}

​

console.log("Define: Factorial");

var factorial = Y(function(recurs) { 

  console.log("Factorial Wrapper");

  return function(x) {

    console.log("Factorial " + x);

    return x === 0 ? 1 : x * recurs(x-1);

  };

});

​

console.log("===Start Trace===")

console.log(factorial(2));

console.log("===End Trace===")