Javascript IIFE anonymous function

Question

I've been trying to understand exactly how IIFEs work in regards to anonymous functions. I understand their use in avoiding global variable collisions and that they create their own local scope.

I'm not clear on what happens when an anonymous function like this is called.

(function () {
  var myVar = 'foo';
  }
)()

If this is immediately invoked and it is not available in the global scope, where is it available? How would I access myVar?

you cannot access to myVar, IIFE work as a well protected singleton — ale, Dec 20 '14 at 17:43
You won't access it unless you make it a property of `window` or something else in the scope above. — Alexander O'Mara, Dec 20 '14 at 17:43
Would that mean passing in (window) to the invoking parenthesis? — byrdr, Dec 20 '14 at 17:44
@byrdr No, but you could, it will help minification. You would need to do `window.myVar` in either case. — Alexander O'Mara, Dec 20 '14 at 17:46
OK, that makes sense. So unless I explicitly define access to something like "window" they will not be accessible on their own. — byrdr, Dec 20 '14 at 17:48
Yes - that, in fact is one of the reasons you'd write code like that: to protect the global namespace from pollution, so that your script won't step on variables used by other scripts, and vice-versa. — Pointy, Dec 20 '14 at 17:52

ale · Answer 1 · 2014-12-20T18:00:52.690

This notation is known as module pattern

var myModule = function () {
      var privateVar = "foo";
      function privateMethod() {
       return "bar";

      }

      return {
        publicMethod : function(){
          return 'foo';
        }
      }
}

To make this module completely isolated from the global scope, we can close it in a IIFE

(function (setUp) {
      var privateVar = setUp;
      function privateMethod() {
       return "bar";

      }

      return {
        publicMethod : function(){
          return 'foo';
        }
      }
})(window.setUp);

Javascript IIFE anonymous function

1 Answers1

Linked