Here are 10 Angular JavaScript interview questions to strengthen your preparation.
AngularJS is a JavaScript-based open-source web framework for front-end development. Angular JavaScript is maintained by Google and a community of individuals and corporations to address many of the challenges encountered in developing single-page applications.
It aims to simplify the development and the testing of such applications by providing a framework for client-side model–view–controller (MVC) and model–view–ViewModel (MVVM) architectures, along with components commonly used in rich Internet applications. Source: Wikipedia.
1. What is Angular JS?
A Structural framework that lets you use HTML as your language for templates. AngularJS also allows you to extend the syntax of HTML. It provides flexibility to avoid writing hundreds of initialization codes just to get started.
Google started to work with Angular JS in 2009.
2. What is a Model-View-Controller (MVC)?
MVC is a software design pattern for developing web applications. A Model View Controller pattern is made up of the following three parts:
A model can be defined as the data that will be used by the program. An example of a model is a database.
A view is a way of displaying objects (user interfaces) within an application. The end-users interact with the application through a view.
A controller is responsible for updating both models and views. It accepts input from users as well as performs the equivalent update. The response to user actions and events is handled by the controller.
3. What is the use of “routes” in Angular JS?
It enables the creation of different URLs for different content in the application. Angular js route enables users to bookmark content of different URLs.
4. What are some unique features of Angular JavaScript?
- Registering Callbacks are not required in Angular JS. This feature makes Angular JS code simple and easy to debug.
- The applications which have been created using Angular JS never influence the DOM (Document Object Model).
- Angular JS can be used to transfer the data to and from the user interface. It also helps to eliminate issues like validating a form, validation error display, etc.
Must Read: 25 Effective Software Engineering Interview Questions
5. What are the types of custom directives in Angular JS?
The following custom directives are present in Angular JS:
- Element directives: Element directive works when the matching element is confronted.
- CSS class directives: It starts when the same CSS style matches.
- Comment directives: When a matching comment found, the comment directive gets activated.
- Attribute directives: Attribute directives come into the picture when matching/same attribute is confronted.
6. What are the types of bootstrapping in Angular JS?
AngularJS interview questions are incomplete without a question or two on bootstrapping. Starting or initializing the application is called bootstrapping. Angular JS supports two types of bootstrapping:
- Automatic Bootstrapping: Add the ng-app at the root of an application. After finding the ng-app statement, angular JS loads the associated module and then the compilation of DMO happens.
- Manual Bootstrapping: Use manual bootstrapping to get more control over the initialization of your angular app. It provides control over how and when to start the app. Manual bootstrapping is much useful when another operation will get performed before waking up the Angular JS and compilation of the page.
7. Explain any Angular JS service using the code?
Services are the objects or functions used to carry out specific tasks.
It can be built by a developer in Angular JS. Developers can define their own services.
By registering the service’s name and service factory function, custom services can be defined. There are almost 30 to 35 inbuilt services are available for instant use. $timeout is one such Angular JS service.
$timeout service is being used to change the value in a specified number of milliseconds. This service is useful for changing the value after a predefined time limit.
Input Code:
GoApti code will change this header will change after 3 seconds:
{{myHeader}}
The $timeout service works after a specified number of milliseconds.
Output:
“This code will change the value to default after 3 seconds”
8. Explain the security features in Angular JS.
There are built-in protections provided by Angular JS. Some of the security features are:
- It prevents Cross-site scripting. It is a hacking technique where a hacker can send a request form and can get confidential or private information easily.
- It also prevents injection attacks HTML.
- It prevents XSRF (Cross-site request forgery) protection for server-side communication. Angular JS handles it by the “Auth token” mechanism. Whenever users logins for the very first time, it sends a user id and password to the server, and in turn, it will return an Auth token. this authorized token does the authentication in all future transactions.
9. Explain the Syntax to show the entered password using Angular JS?
Using the below code, the Developer can switch the visibility of the password to the user.
Input Code:
Password: id=”myInput”>
Show Password
10. What is the difference between link and compile in Angular JavaScript?
- Compile function: It is used for template DOM manipulation and collects all of the directives.
- Link function: It is used for registering DOM listeners as well as for instance, DOM manipulation. It is executed once the template has been cloned.
What other important Angular interview questions are you aware of? We’d love to hear from you in the comments.
