Tech Junkie Blog - Real World Tutorials, Happy Coding!: AngularJS SPA : Refactor Code to Not Use Global Variables (Bank App)

Sunday, June 26, 2016

AngularJS SPA : Refactor Code to Not Use Global Variables (Bank App)

In the previous blog post we got AngularJS to work with a module and a controller. However, we put everything in the global scope. The problem with that is that there are many JavaScript libraries that might be using the same variables as we are, or if we are working with other developers, there might be some unforeseen conflicts. The way we can mitigate this problem is to wrap our modules and controllers in an anonymous function. Think of an anonymous function as a wrapper or a container to hold our modules and controllers. Another term developers like to refer to anonymous function is an IIFE. Whatever it's called it's always good practice to avoid putting things in the global environment if it can be avoided.

Here are the steps to take the modules and controllers out of the global environment:

1. First let's wrap the module in an anonymous function. The source code for the app.js file should look like the following

(function(){
    'use strict';

    var app = angular.module('bankApp',['bankController']);
    
})();

The code above wraps the application in anonymous function and assigned to the variable call "app"

2. Now open the "bankController.js" in the "controllers" folder and wrap the "bankController" in anonymous function, the source code for the file should look like the following

(function(){
   'use strict';

angular.module('bankController',[])
 .controller('bankController',["$scope",function($scope){
  $scope.bankAppName="My Bank Application";
}]); 
    
})();

3. Open up the "index.html" file and make sure the source code looks like the following.

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="utf-8">
 <title>Bank Application</title>
 <link rel="stylesheet" type="text/css" href="app.css">
</head>
<body ng-app="bankApp" ng-controller="bankController">
{{bankAppName}}
<script type="text/javascript" src="js/lib/angular/angular.js"></script>
<script type="text/javascript" src="js/app.js"></script>
<script type="text/javascript" src="js/controllers/bankController.js"></script>
</body>
</html>

4.If you open the file you will see that application still works