Angularjs Interview Questions and Answers

Last updated on Feb 07, 2024
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Angularjs Interview Questions

A JavaScript client-side framework, AngularJS offers a structured method of building websites and applications. It is a structural framework which is used to develop the dynamic web app. We have an impressive collection of AngularJS Interview Questions that is a must-read for all developers and designers!. Its JavaScript library enforces the Model View Controller (MVC) framework. AngularJS I said to be one of the most widely used JavaScript client-side frameworks in the world.

Quick Facts About AngularJS
What is the latest version of Angular? Angular 11.0 released on 11th November 2020
When did angular release? 4th May 2018
When was Angular first released? Angular 2.0 and released on 14th September 2016
What language does Angular use? TypeScript

Our angular questions has been created by seasoned Angular experts. It shall help you to answer some of the most frequently asked questions during an job interview.

Most Frequently Asked Angularjs Interview Questions

Here in this article, we will be listing frequently asked Angularjs Interview Questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.

Q1. What is the use of a filter in AngularJS?
Answer

It is used to format the value of the expression to display the output. AngularJS enables us to apply filter. It can be added to expressions by using the pipe character |, followed by a filter.

Example

<div ng-app="myApp" ng-controller="personCtrl">    
<p>The name is {{ firstName | uppercase }}</p>    
</div>    
<script>    
angular.module('myApp', []).controller('personCtrl', function($scope) {    
    $scope.firstName = "Umesh",    
    $scope.lastName = "Singh"
});
</script>

Q2. What are the features of AngularJS?
Answer
  • Easy to implement MVC.
  • Makes HTML more intuitive and easier to maintain.
  • Easier to access, manipulate, and implement.
  • Applications use very less code compared to other JavaScript applications.
  • Supports test-driven development approach (TDD)
  • Unit Testing
Q3. What do you mean by data binding?
Answer

Data binding is automatic synchronization of the data between the view and model components. Data binding lets you treat the model components as a single source of truth in your applications. The view component is a projection of the model. When the model changes, the view will reflect the change, and vice versa.

NOTE: This information is likely to be asked in angularjs interview questions.

Q4. What are the differences between link and compile?
Answer

The Compile function is used for templating DOM Manipulation and for collecting the directives. The Link function is used for registering the DOM listeners as well as for an instance the DOM manipulation. This function gets executed after the template has been cloned.

Q5. How to handle 'Loading chunk failed' error in Angularjs?
Answer

In Angular, the lazy loading feature is a design pattern to load the NgModules as needed, which then splits the build file into multiple chunks and loads them on-demand to speed up the page load.

Using the lazy loading feature may result with you having to face a common issue “Loading chunk [number] failed” while navigating any route and here are the steps to fix it: This is the exact error displayed:

Error: Uncaught (in promise): Error: Loading chunk 0 failed.

This error’s main culprit is browser caching. To solve this, we need a global error handling while forcing the app to reload if any of the chunks fail to load.

import { ErrorHandler } from '@angular/core';
@Injectable()
export class GlobalErrorHandler implements ErrorHandler {
handleError(error: any): void {
const chunkFailedMessage = /Loading chunk [\d]+ failed/;
if (chunkFailedMessage.test(err.message)) {
window.location.reload();
}
}
}

This above GlobalErrorHandler class we have created will have only one job. That is, checking all the error messages for Loading chunk [number] failed and if there is one, then Angular forces to reload the app in order to load all the chunks again.

Q6. What is bootstrapping in Angularjs?
Answer

Bootstrapping is a term for initializing the Angular app. Both automatic and manual bootstrapping is supported in AngularJS. Automatic Bootstrapping is done by adding an ng-app directive to the root of the application. Manual Bootstrapping provides control on how and when to initialize the app. It is useful in performing any operation before Angular compiles the page.

Q7. What are the different types of filters in AngularJS?
Answer
  • Currency It formats a number to a currency format.
  • Date It formats a date to a specified format
  • Filter It selects a subset of items from an array.
  • JSON It formats an object to a Json string
  • Limit It is used to limit an array/string, into a specified number of elements/characters.
  • Lowercase It formats a string to lower case
  • Uppercase It formats a string to upper case.
  • Number It formats a number to a string.
Q8. What is Single Page Application? How can the SPA be implemented with Angular?
Answer

Single Page Applications are web apps that load an HTML page and dynamically update it as and when users interact with the app. However, please note that in an SPA, the page will never reload, though parts of that page may get refreshed. This functionality reduces the trips to the server. SPA can be implemented with Angular through Angular routes.

Q9. What is a Singleton pattern? How do you use it?
Answer

The singleton pattern allows us to limit the instantiation of a class in order to have only one object. We can use the dependency injection and services for enabling the singleton pattern. Whenever the singleton pattern is enabled, the class will create the object and return a reference in the next call.

NOTE: Learn the basic concept of Singleton pattern and work to crack the angular interview questions and answers for experienced.

Q10. What are promises in AngularJS?
Answer

Promises are provided by the in-built $qservice in AngularJS. It is used to provide a way to execute multiple asynchronous functions in series by basically registering them with an object of promise. Promises are used widely in Angular, Javascript and the ES6 specifications equally.

Here’s an example of a promise object in Angular:

Example

.run(function(getData) {
  var promise = getData()
    .then(function(string) {
      console.log(string)
    })
})

Development History of Angular JS

AngularJS was developed by Misko Hevery and Adam Abrons in 2009. The framework is maintained by Google now.

It is not a single piece in the overall puzzle of building the client-side of a web application. It also handles all of the AJAX and DOM code you once wrote by hand and puts it in a clear structure.

Advantages of AngularJS
  • Easy to implement MVC.
  • Makes HTML more intuitive and easier to maintain.
  • More comfortable to access, manipulate, and implement.
  • Applications use very less code compared to other JavaScript applications.
  • Supports the test-driven development approach (TDD)

Though every interview is different, we can help you crack your next interview with the most commonly asked Angularjs Interview Questions, which will help you achieve success.

Installation Steps
  • Open the link https://angularjs.org/
  • You will see two options on this page - View on GitHub and Download.
  • Click the download button, and it will start downloading angular.min.js.
  • Create an HTML page and include the following AngularJS JavaScript file
    http://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js with script tag
  • Run the HTML page in the browser.
Reviewed and verified by Umesh Singh
Umesh Singh

My name is Umesh Singh having 11+ experience in Node.JS, React JS, Angular JS, Next JS, PHP, Laravel, WordPress, MySQL, Oracle, JavaScript, HTML and CSS etc. I have worked on around 30+ projects. I lo...