Question

I’m trying to learn the JavaScript module pattern referenced here. Everything looks great but I keep seeing different ways to create the module.

In the article referenced above he access the module’s public methods by using YAHOO.myProject.myModule.init(); without calling new. But then I’ve seen a few people do something like var module = new YAHOO.myProject.myModule();. Should new be used and why?

Answer 1

There is no right or wrong answer to this.

Sometimes a module will contain an object, where no new keyword is needed.

define( [], function() {
   return {
      foo: "bar"
   };
};

Sometimes a module will contain a constructor for an object, where a new keyword is needed.

define( [], function() {
   return function() {
      this.foo = "bar";
   };
};

Sometimes a module will contain a function that returns new objects, where no new keyword is needed.

define( [], function() {
   var SomeConstructor = function() {
      this.foo = "bar";
   };
   return function() {
      return new SomeConstructor();
   };
};

Usage depends partially on what you are trying to accomplish and partially on your teams coding preference.