Private vs Public Javascript Functions

Question

can someone please explain what the difference is between these two functions?

(function(Engine, $, undefined) { //hidden from scope
    //public function below
    Engine.Init = function() {
        console.log("IM PUBLIC");
    }

    //anonymous functions below
    function Login() {
        console.log("IM PRIVATE");
    }
})( window.Engine = window.Engine || {}, jQuery );

Specifically, I'd like to know why Engine.Init() is available in the Console but Login isn't.

Answer 1

Init is a property of the Engine object that refers to a function.
You can access it like any other property.

Login is a local variable within the anonymous, "immediately invoked function expression" (IIFE); like other local variables, its name is only visible within the declaring function

Answer 2

Engine is global because of the parameters:

(window.Engine = window.Engine || {}, jQuery)

and available in the global namespace, if you did:

Engine.Login = function(){}

That would be available globally.

The function Login is only available inside the scope of the anonymous self executing function.