Exposing a method which is inside a closure

Question

When we are creating a method inside a closure it becomes private to that closure and can't be accessed until we expose it in some way.

How can it be exposed?

Answer 1

You can return a reference to it...

var a = function() {

   var b = function() {
      // I'm private!
      alert('go away!');
   };

   return {
      b: b // Not anymore!
   };

};

See it on jsFiddle.

You could also bind it to the window object. But I prefer the method above, otherwise you are exposing it via a global variable (being a property of the window object).

Answer 2

You need to pass it to the outside in some manner.

Example: http://jsfiddle.net/patrick_dw/T9vnn/1/

function someFunc() {

    var privateFunc = function() {
        alert('expose me!');
    }

    // Method 1: Directly assign it to an outer scope
    window.exposed = privateFunc;

    // Method 2: pass it out as a function argument
    someOuterFunction( privateFunc );

    // Method 3: return it
    return privateFunc;
}

someFunc()(); // alerts "expose me!"

function someOuterFunction( fn ) {
    fn(); // alerts "expose me!"
}

window.exposed(); // alerts "expose me!"