Kuul Stuff : Blog

AngularJS is the Javascript framework for website development. It is widely popular for the features including modularity and separation of concerns. Here are some of the keywords you must be familiar with in order to build web applications with AngularJS.

Steps to Create

Here are the steps to create an application with AngularJS:

1. Download the latest angular js file from the Angular website. Or, you can include the CDN in the script tag of your web page
2. Bootstrap the application with Angular by using ng-app
3. Create a controller in the app
4. Create the HTML view in the body
5. Run the application in a web browser

Angular Keywords

1. Directives: AngularJS uses the directives to convert static HTML into dynamic Document Object Model (DOM) with the help of special attributes such as:
   1. ng-app: To determine which part of the page will use Angular. It will load the respective module in that part.
   2. ng-controller: To identify which Javascript controller should be used in that part of the page.
   3. ng-model: To determine the binding between model and the input field ensuring two way binding.
2. Modules: Modules ensure separation of concerns in manageable units. It can comprise all the directives, expressions, controllers, services, and filters. Modules specify how an application can be bootstrapped. Advantages of using modules are:
   1. Easy to declare and understand
   2. Code can be packaged as reusable chunks
   3. Easy to load in any order or load in parallel
   4. Faster unit tests because only relevant modules can be tested
   5. Modules can be used in end-to-end tests to override configuration
3. Controllers: Controllers are defined by a JavaScript constructor function that is used to augment the Scope. They carry the business logic and determine how the view and model interact. The scope is a mandatory parameter that is passed to the controller.
   1. A controller is attached to the DOM via the ng-controller directive.
   2. Then,  Angular instantiates a new Controller object, using the specified Controller‘s constructor function.
   3. A new child scope will be created and made available as an injectable parameter to the Controller’s constructor function as $scope.
4. Expressions: Expressions are Javascript code snippets that are placed in dual curly braces. {{ }}. They are used to load model directly into the view. Advantages of using expressions are:
   1. Evaluated in the current scope not in the global window
   2. Evaluation of errors is either null or undefined
   3. Loops, functions, exceptions cannot be handled in Angular expressions
   4. You need to create a controller for complex Javascript functions






5. Scope: Scope is an object of the application model. It refers to the current context or boundary of the application. Scope establishes a connection between application controller and view. Some of the characteristics of the scope are:
   1. Used to observe model mutations
   2. Used to propagate events similar to DOM events
   3. Can be nested to limit the properties and behavior of application components
   4. A child scope can inherit from the parent scope
   5. Provide a context for expressions to evaluate

There are some other key terms such as filters, forms, routing, and services which are key to an Angular application.