Introduction to Angularjs

ANGULARJS
HTML enhanced for web apps!

What is ANGULARJS?
• It’s not a JavaScript library (As they say). There are no
functions which we can directly call and use.
• It is not a DOM manipulation library like jQuery. But it
uses subset of jQuery for DOM manipulation (called
jqLite).
• Focus more on HTML side of web apps.
• For MVC/MVVM design pattern
• AngularJS is a Javascript MVC framework created by
Google to build properly architectured and
maintenable web applications.

Philosophy
“ANGULARJS is what HTML could have been if it had been designed for web application development.”
“”ANGULARJS is built around the philosophy that declarative code is better than imperative code while building
UIs and wiring different components of web application together.”
<!doctype html>
<html ng-app>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.min.js"></script>
</head>
<body>
<div>
<label>Name:</label>
<input type="text" ng-model="yourName" placeholder="Enter a name here">
<hr>
<h1>Hello {{yourName}}!</h1>
</div>
</body>
</html>

Why ANGULARJS?
• Defines numerous ways to organize web application at client side.
• Enhances HTML by attaching directives, custom tags, attributes, expressions, templates within HTML.
• Encourage TDD
• Encourage MVC/MVVM design pattern
• Code Reuse
• Good for Single Page Apps (SPA)
• Cool Features -> Next Slide

Key Features of ANGULARJS
• Declarative HTML approach
• Easy Data Binding : Two way Data Binding
• Reusable Components
• MVC/MVVM Design Pattern
• Dependency Injection
• End to end Integration Testing / Unit Testing
• Routing
• Templating
• Modules
• Services
• Expressions
• Filters
• Directives
• Form Validation
• $scope, $http, $routeProvider…

MVC : Model View Controller
View
ControllerModel
1. Event or User Action
or View Load
2. Maps to particular Model
after fetching the data
3. Implement the
Business Logic on
response data and
Bind it to View
View :
• Renders the Model data
• Send User actions/events to controller
• UI
Controller:
• Define Application Behavior
• Maps user actions to Model
• Select view for response
Model:
• Business Logic
• Notify view changes
• Application Functionality
• Data in general

MVVM: Model View ViewModel
View
ViewModelModel
UI
Presentation LogicBusiness Logic
and Data
• User actions, commands
• Data binding
• Notifications
• Data Access
• Update ViewModel about change

ng-app
Use this directive to auto-bootstrap an application.
Only one ng-app directive can be used per HTML document
<html ng-app>

HTML Compiler
Angular's HTML compiler allows the developer to teach the browser new HTML syntax. The compiler allows
you to attach behavior to any HTML element or attribute and even create new HTML elements or attributes
with custom behavior. Angular calls these behavior extensions directives.
Compiler is an angular service which traverses the DOM looking for attributes. The compilation process
happens in two phases.
Compile: traverse the DOM and collect all of the directives. The result is a linking function.
Link: combine the directives with a scope and produce a live view. Any changes in the scope model are
reflected in the view, and any user interactions with the view are reflected in the scope model. This makes
the scope model the single source of truth.
http://docs.angularjs.org/guide/compiler

Directive
The directives can be placed in element names, attributes, class names, as well as
comments. Directives are a way to teach HTML new tricks.
A directive is just a function which executes when the compiler encounters it in the DOM.
<input ng-model='name'>
Custom Defined Directives
<span draggable>Drag ME</span>

Expression
Expressions are JavaScript-like code snippets that are usually placed in bindings such as {{
expression }}
<body>
1+2={{1+2}}
</body>

Forms
Form and controls provide validation services, so that the user can be notified of invalid
input. This provides a better user experience, because the user gets instant feedback on
how to correct the error.
<input type="text" ng-model="user.name" name="uName" required />
<button ng-click="update(user)“ ng-disabled="form.$invalid ||
isUnchanged(user)">SAVE</button>

Module
Modules declaratively specify how an application should be bootstrapped.
There can be multiple modules in an app
Those could be interdependent too.
// declare a module
var myAppModule = angular.module('myApp', [--here goes the dependent Modules--]);
Modules are configured with routes, controllers, models etc.

Routing
It Is used for deep-linking URLs to controllers and views (HTML partials). It watches $location.url() and
tries to map the path to an existing route definition.
$routeProvider.when('/Book', {
template: 'examples/book.html',
controller: BookCntl,
});
$routeProvider.when('/Book/chapter01', {
template: 'examples/chapter01.html',
controller: ChapterCntl,
});

Scope
Scope is an object that refers to the application model.
It is an execution context for expressions.
Scopes are arranged in hierarchical structure which mimic the DOM structure of the
application.
Scopes can watch expressions and propagate events.
Actually the ViewModel of MVVM.
$scope

Dependency Injection
Dependency Injection (DI) is a software design pattern that deals with how code gets hold
of its dependencies.

Filters
Angular filters format data for display to the user.
{{ expression [| filter_name[:parameter_value] ... ] }}
{{ uppercase_expression | uppercase }}
{{ expression | filter1 | filter2 }}
Can create custom filters

Resources
Documentation
• AngularJS Developer Guide
• AngularJS API
• AngularJS Tutorial
Videos
• AngularJS Fundamentals In 60-ish Minutes
• Introduction to Angular JS
• AngularJS end-to-end web app tutorial Part I

Manish
Shekhawat
twitter.com/manishekhawat
www.facebook.com/manishekhawat

Introduction to Angularjs

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