Hi everyone in this article I’m explaining about AngularJs. What is angularjs and why we use angularjs.

Introduction:

Angularjs is very powerful JavaScript library. It is used in single page application (SPAs) project. It is extends HTML DOM with additional attribute and make it more responsive to user action. Angular js is open source completely free, and used by thousands of developer around the world. It is licensed under the Apache license version 2.0.

What is Angularjs?

AngularJS is an open source web application framework. It was originally developed in 2009 by Misko Hevery and Adam Abrons. It is now maintained by Google. Its latest version is 1.3.14.

Angularjs is a structural framework for dynamic web application. It lets you use HTML as your template language and lets you extend HTML’s syntax to express your applications components clearly and succinctly. Angular’s data binding and dependency injection eliminate much of the code you currently have to write and it all happens within the browser, making it an ideal partner with any server technology.

Features:

1.       Angularjs is powerful JavaScript based development framework to create RICH

Internet Application (RIA).

2.       Angularjs provides developers options to write client side application (Using

JavaScript) in a clean MVC (model view controller) way.

3.       Application written in angularjs is cross-browser compliant. Angularjs

automatically handles JavaScript code suitable for each browser.

4.       Angularjs is open source, completely free and used by thousands of

developers around the world it is licensed under the apache license version 2.0.

Core Features:

Data-Binding: It is the automatic synchronization of data between model and view

components.

Scope: These are object that refer to the model. They act as a glue between

controller and view.

Controller: These are JavaScript function that are bound to a particular scope.

Services: Angularjs come with several built-in services for example $http to make

an XMLHttpRequest. These are singleton object which are instantiated only once in

app.

 Filters: These select a subset of items from an array and returns a new array.

Directives: Directives are markers on DOM elements (such as elements, attributes,

css etc). These can be used to create Custom HTML tag that serve as new, custom

widgets. Angularjs has built-in directives (ngBind, ngModel…).

Templates: These are the rendered view with information from the controller and

model. These can be a single file (like index.html) or multiple views in one page

using "partials".

Routing: It is concept of switching views.

Model View Whatever:MVC is a design pattern for dividing an application into different parts (called Model, View and Controller), each with distinct responsibilities. AngularJS does not implement MVC in the traditional sense, but rather something closer to MVVM (Model-View-ViewModel). The Angular JS team refers it humorously as Model View Whatever.

Deep Linking:Deep linking allows you to encode the state of application in the URL so that it can be bookmarked. The application can then be restored from the URL to the same state.

Dependency Injection:Angularjs has built-in dependency injection subsystem that helps the developer by making the application easier to develop, understand and test.

Concepts:

Following diagram depicts some important parts of AngularJS which we will discuss in detail in the subsequent chapters.

Advantage of Angularjs:

1.      Angularjs provides capability to create single page application in a very clean

and maintainable way.

2.       Angularjs provide data binding capability to HTML thus giving user a rich and

responsive experience.

3.       Angularjs code is unit testable.

4.       AngularJS uses dependency injection and make use of separation of concerns.

5.       AngularJS provides reusable components.

6.       With AngularJS, developer write less code and get more functionality.

7.       In AngularJS, views are pure html pages, and controllers written in JavaScript

do the business processing.

Disadvantages of AngulaJS:

Though AngularJS comes with lots of plus points but same time we should

consider the following points:

Not Secure : Being JavaScript only framework, application written in AngularJS are

not safe. Server side authentication and authorization is must to keep an

application secure.

Not degradable: If your application user disables JavaScript then user will just see

the basic page and nothing more.

The AngularJS Components:

The AngularJS framework can be divided into following three major parts:

ng-app : This directive defines and links an AngularJS application to HTML.

ng-model : This directive binds the values of AngularJS application data to HTML input controls.

ng-bind : This directive bins the AngularJS Application data to HTML tags.