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JavaScript The Module Pattern in JavaScript

Anthony c
Anthony c
20,907 Points

Three steps to modularize?

We start with



Then we add (); to the end of the function to make it call:



then we put that inside a variable with parenthesis

var myVariable = ();

Which results in the below (a variable holding an IIFE):

var myVariable = (function(){


and now we have module? Or at least one potential (and basic) pattern for a module?

2 Answers

Julie Myers
Julie Myers
7,627 Points

What you have is the super duper basics of the model pattern. There are different flavors of the module pattern. For example:

var yourModule = (function(){
  var universe = "The Great Beyond";
  var yourPublicFunction = function(){
    return 'Hello World!';

  return {
    universal: universe,
    yourPublicFunction: yourPublicFunction
When the object literal was returned it was returned into the yourModule
variable. What this means is that we’ll have a reference to the object
returned via the yourModule variable. We can execute ‘yourPublicFunction’
as follows:
console.log(yourModule.yourPublicFunction()); // returns 'Hello World!'
console.log(yourModule.universal); // "The Great Beyond'"

Remember, we can only access the ‘yourPublicFunction’ function object via
yourModule. We can’t access or invoke the ‘yourPublicFunction’ function object
directly. For example:
console.log(yourPublicFunction()); // JavaScript error!

When all is said and done the module patter is essentially an IIFE assigned to a variable.

Michael Kellogg
Michael Kellogg
774 Points

Honestly, this video was the most confusing one I've watched on Treehouse. He jumps into things without showing how he sets them up (e.g. importing "underscore"), and skips onto a new pattern, referring to a previous pattern as something different, several times. What, for example, is the difference between "the module pattern" and "the module exports pattern" ? And that syntax with the double pipes (aka "or")? I didn't understand that at all, how it works or what it was supposed to be used for. Then he jumps into this "sub" pattern which just made it worse. I watched this video several times and it never got better. Moving on.

Ali Raza
Ali Raza
13,633 Points

There is a great article:

On Javascript Modular Patterns I would recommend a read. It covers the basics and some advance concepts.