ng-app − This directive starts an AngularJS Application.
ng-init − This directive initializes application data.
ng-model − This directive binds the values of AngularJS application data to HTML input controls.
ng-repeat − This directive repeats html elements for each item in a collection.

ng-app directive

ng-app directive starts an AngularJS Application. It defines the root element. It automatically initializes or bootstraps the application when web page containing AngularJS Application is loaded. It is also used to load various AngularJS modules in AngularJS Application. In following example, we’ve defined a default AngularJS application using ng-app attribute of a div element.

…

</div>

ng-init directive

ng-init directive initializes an AngularJS Application data. It is used to put values to the variables to be used in the application. In following example, we’ll initialize an array of countries. We’re using JSON syntax to define array of countries.

<div ng-app = “” ng-init = “countries = [{locale:’en-US’,name:’United States’},

{locale:’en-GB’,name:’United Kingdom’}, {locale:’en-FR’,name:’France’}]”>

…

</div>

ng-model directive

This directive binds the values of AngularJS application data to HTML input controls. In following example, we’ve defined a model named “name”.

…

<p>Enter your Name: <input type = “text” ng-model = “name”></p>

</div>

ng-repeat directive

ng-repeat directive repeats html elements for each item in a collection. In following example, we’ve iterated over array of countries.

…

<p>List of Countries with locale:</p>

<ol>

</li>

</ol>

</div>

Example

Following example will showcase all the above mentioned directives.

testAngularJS.htm

<html>

<head>

<title>AngularJS Directives</title>

</head>

<body>

<h1>Sample Application</h1>

<div ng-app = “” ng-init = “countries = [{locale:’en-US’,name:’United States’},

{locale:’en-GB’,name:’United Kingdom’}, {locale:’en-FR’,name:’France’}]”>

<p>Enter your Name: <input type = “text” ng-model = “name”></p>

<p>Hello <span ng-bind = “name”></span>!</p>

<p>List of Countries with locale:</p>

<ol>

</li>

</ol>

</div>

</script>

</body>

</html>

Output

Open textAngularJS.htm in a web browser. Enter your name and see the result.

AngularJS – Expressions

Expressions are used to bind application data to html. Expressions are written inside double braces like {{ expression}}. Expressions behaves in same way as ng-bind directives. AngularJS application expressions are pure javascript expressions and outputs the data where they are used.

Using numbers

<p>Expense on Books : {{cost * quantity}} Rs</p>

Using strings

<p>Hello {{student.firstname + ” ” + student.lastname}}!</p>

Using object

<p>Roll No: {{student.rollno}}</p>

Using array

<p>Marks(Math): {{marks[3]}}</p>

Example

Following example will showcase all the above mentioned expressions.

testAngularJS.htm

<html>

<head>

<title>AngularJS Expressions</title>

</head>

<body>

<h1>Sample Application</h1>

<div ng-app = “” ng-init = “quantity = 1;cost = 30;

student = {firstname:’Mahesh’,lastname:’Parashar’,rollno:101};

marks = [80,90,75,73,60]”>

<p>Hello {{student.firstname + ” ” + student.lastname}}!</p>

<p>Expense on Books : {{cost * quantity}} Rs</p>

<p>Roll No: {{student.rollno}}</p>

<p>Marks(Math): {{marks[3]}}</p>

</div>

</script>

</body>

</html>

Output

Open textAngularJS.htm in a web browser. See the result.

So, this brings us to the end of blog. This Tecklearn ‘Using Directives and Expressions in Angular JS’ blog helps you with commonly asked questions if you are looking out for a job in Angular JS and Front-End Development. If you wish to learn Angular JS and build a career in Front-End Development domain, then check out our interactive, Angular JS Training, that comes with 24*7 support to guide you throughout your learning period. Please find the link for course details:

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Introduction to Angular
Comparison between front-end tools
Angular Architecture
Building blocks of Angular
Angular Installation
Angular CLI
Angular CLI commands
Angular Modules

Angular Components and Data Binding

Working of Angular Applications
Angular App Bootstrapping
Angular Components
Creating A Component Through Angular CLI
Ways to specify selectors
Template and styles
Installing bootstrap to design application
Data Binding
Types of Data Binding
Component Interaction using @Input and @Output decorator
Angular Animations

TypeScript

What is TypeScript
Need of TypeScript
How to install TypeScript
Nodemon for monitoring changes
Interfaces in Class, String Templates, Maps,
Sets and Object Restructuring

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Angular Directives
@Component Directive
Structural Directives
Attribute Directives
Custom Directives
Pipes
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Chaining pipes
Custom pipes
Pipe Transform Interface & Transform Function
Pure and Impure pipes

Angular Services and Dependency Injection

Angular service
Need for a service
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Hierarchical Injector
Injecting A Service into Another Service
Observables
RxJS Library
Angular’s Interaction with Backend
Parts of an Http Request
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Forms in Angular
What are their functions
Advantages of Forms
Various Types of Forms
What is Angular Validation and Model driven approach

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Angular Routing
Angular Routing benefits and features
Building a single page application and updating it dynamically with Angular Routing
What is Parameter Routing
Router Lifecycle Hooks and Child Routes

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What is Authentication?
Authentication and authorization
Types of Authentication
Where to store tokens?
JSON Web Tokens (JWT)
Authentication in Angular application
Security threats in web application

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Setup of various tools for testing
Testing services in Angular Framework
E2E and Document Object Model testing

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