Angular JS Interview Question Answer for Freshers and Experienced
Categories: Angular JS
What is AngularJS?
AngularJS is a JavaScript framework used for creating single web page applications. It allows you to use HTML as your template language and enables you to extend HTML’s syntax to express your application’s components clearly.
What are the key features of AngularJS?
Scope
Controller
Model
View
Services
Data Binding
Directives
Filters
Testable
Explain function scope in AngularJS
Scope refers to the application model. It acts like a glue between the application controller and the view. Scopes are arranged in a hierarchical structure and impersonate the DOM (Document Object Model) structure of the application. It can watch expressions and propagate events.
Explain services in AngularJS
AngularJS services are the singleton objects or functions that are used for carrying out specific tasks. It holds some business logic.
What is Angular Expression? Explain the key difference between angular expressions and JavaScript expressions
Like JavaScript, Angular expressions are code snippets that are usually placed in binding such as {{ expression }}
The key difference between the JavaScript expressions and Angular expressions is:
Context: In Angular, the expressions are evaluated against a scope object, while the JavaScript expressions are evaluated against the global window
Forgiving: In Angular expression, evaluation is forgiving to null and undefined, while in JavaScript undefined properties generate TypeError or ReferenceError
No Control Flow Statements: Loops, conditionals or exceptions cannot be used in an angular expression
Filters: You can use filters to format data before displaying it.How can you initialize a select box with options on page load?
You can initialize a select box with options on page load by using ng-init directive.
<div ng-controller = ” apps/dashboard/account ” ng-switch
On = “! ! accounts” ng-init = ” loadData ( ) “>
What are directives? Name some of the most commonly used directives in AngularJS application
A directive is something that introduces new syntax. They are like markers on the DOM element, which attaches a special behavior to it. In any AngularJS application, directives are the most important components.
Some of the commonly used directives are:
1) ng-model
2) ng-App
3) ng-bind
4) ng-repeat
5) ng-show
How Angular JS routes work?
AngularJS routes enable you to create different URLs for different content in your application. Different URLs for different content enable the user to bookmark URLs to specific content. Each such bookmarkable URL in AngularJS is called a route
A value in Angular JS is a simple object. It can be a number, string, or JavaScript object. Values are typically used as configuration injected into factories, services, or controllers. A value should belong to an AngularJS module.
Injecting a value into an AngularJS controller function is done by adding a parameter with the same name as the value
What is data binding in AngularJS?
Automatic synchronization of data between the model and view components is referred to as data binding in AngularJS. There are two ways for data binding
Data mining in classical template systems
Data binding in angular templates
What are the benefits of AngularJS?
Benefits of AngularJS are:
Registering Callbacks: There is no need to register callbacks. This makes your code simple and easy to debug.
Control HTML DOM programmatically: Applications which are created using Angular are not required to manipulate the DOM.
Transfer data to and from the UI: AngularJS helps to eliminate almost all of the boilerplate. It can validate the form, display errors, return to an internal model, and so on.
No initialization code: With AngularJS, you can bootstrap your app easily. You can use auto injected services into your application in Guice.
What is string interpolation in Angular.JS ?
In Angular.js, the compiler during the compilation process matches text and attributes. It uses interpolate service to see if they contain embedded expressions. As part of the normal digest cycle, these expressions are updated and registered as watches.
What are the steps for the compilation process of HTML?
Compilation of HTML process occurs in the following ways
Using the standard browser API, first, the HTML is parsed into DOM
By using the call to the $compile () method, a compilation of the DOM is performed. The method traverses the DOM and matches the directives.
Link the template with a scope by calling the linking function returned from the previous step
Explain directives and their types
During compilation process, when specific HTML function is triggered, it is referred to as directive. It is executed when the compiler encounters it in the DOM.
Different types of directives are:
1) Element directives
2) Attribute directives
3) CSS class directives
4) Comment directives.