Question

I was reading another question, and I saw this:

var basketModule = (function() {
var basket = []; //private

return { //exposed to public
       addItem: function(values) {
            basket.push(values);
        },
        getItemCount: function() {
            return basket.length;
        },
        getTotal: function(){
            var q = this.getItemCount(),p=0;
            while(q--){
                p+= basket[q].price;
            }
        return p;
        }
      }
}());

Can you please explain why does he wrap the function in ( and )‘s? Also, what is the purpose of that return? Couldn’t he just write self.addItem = ... and so on?

Answer 1

When you wrap a function with parantheses, and add () to the end of it, it’s a self executing function.

(function() x() {
 //do something;
})();

And, by returning he’s making basket variable somewhat private. Try getting basketModule.basket from anywhere else, and you’ll get undefined.