Top AngularJS Interview Questions & Answers

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AngularJS Interview Questions

 

AngularJS is a JavaScript open-source front-end web application framework which can be added to an HTML page with a <script> tag. It is one of the highly-sought skills that employer’s look for in a web developer.

Web development has been a lucrative profession with the growth of the internet and businesses creating websites to make their presence known in the internet. High-skilled web developers are in huge demand as businesses not only want to develop websites but also maintain them. As an expert web developer, one should be proficient in many web application frameworks and tools.

If you are appearing for an AngularJS interview and want to be prepared, this article will provide you with some of the common AngularJS Interview Questions (with answers):

 

1) What are Directives in AngularJS?

 

Ans. AngularJS lets you extend HTML with new attributes called Directives. Some of the built-in Directives are – ngBind, ngModel, ngClass, etc.

 

2) What are expressions in AngularJS?

 

Ans. Expressions in AnjularJS are used to bind application data to html. They are written inside double braces like {{expression}} and behaves in same way as ng-bind directives. They are pure JavaScript expressions and outputs the data where they are used. E.g. <p>Name: {{name.title}}</p>

 

3) Explain $scope in Angular?

 

Ans.  ‘$scope’ is an object instance of a controller. ‘$scope’ object instance gets created when ‘ng-controller’ directive is encountered. E.g.

function Function1($scope)

$scope.ControllerName = “Function1”;

function Function2($scope)

$scope.ControllerName = “Function2”;

 

4) What should be the maximum number of concurrent “watches”?

 

Ans. There should be a maximum of 2000 to reduce memory consumption and improve performance.

 

5) What is a digest cycle in AngularJS?

 

Ans. A digest cycle is the code that runs at an interval. This interval may be sometimes simply as fast as possible after the previous one, and sometimes the interval is set.

 

6) How can you decrease digest cycle time?

 

Ans. Digest cycle time can be decreased by decreasing the number of watchers.

 

7) How do you share data between controllers?

 

Ans. By creating an AngularJS service that will hold the data and inject it inside of the controllers.

 

8) Can we force the digest cycle to run manually?

 

Ans. Yes

 

9) What is data binding in AngularJS?

 

Ans. The automatic synchronization of data between the model and view components is referred as data binding in AngularJS.

 

 

10) What is currency filter? What are the two ways to use currency filters?

 

Ans. The “currency” filter includes the “$” Dollar Symbol as the default. here are two ways by which we can use Currency Filter:

  • default, where the Dollar-sign will be used in default. E.g. {{amount | currency}}
  • user-defined, where the user defines the currency. E.g. Indian Currency {{amount | currency:”&# 8377″}}

 

11) What is dependency injection?

 

Ans. Dependency injection is a process where we inject the dependent objects rather than consumer creating the objects.

 

12) What are the benefits of dependency injection?

 

Ans. There are two benefits of dependency injection – Decoupling and Testing.

 

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13) What are the different types of Directive?

 

Ans.

Element directives

Attribute directives

CSS class directives

Comment directives

 

14) Name the types of linking function?

 

Ans. The two of types of linking functions are pre-linking function and post-linking functions.

 

15) What is the difference between one-way binding and two-way binding?

 

Ans. One-way binding implies that the scope variable in the html will be set to the first value its model is bound to.

Two-way binding implies that the scope variable will change its value every time its model is assigned to a different value

 

16) What is “$rootScope” in AngularJS?

 

Ans. A scope provides a separation between View and its Model. Every application has a $rootScope provided by AngularJS and every other scope is its child scope.

 

17) What is SPA (Single page application) in AngularJS?

 

Ans. Single-Page Applications (SPAs) are web applications that load a single HTML page and dynamically update that page as the user interacts with the app.

 

18) Which directive is used to hide elements from the HTML DOM by removing them from that DOM and not changing their styling?

 

Ans. ngIf Directive

 

19) What is controller in AngularJS?

 

Ans. A controller is a set of JavaScript functions which is bound to a specified scope, the ng-controller directive.

 

20) How do you disable a button depending on a checkbox’s state?

 

Ans. Using the ng-disabled directive

 

21) What is Representational State Transfer (REST) in AngularJS?

 

Ans. REST is a style of API that operates over HTTP requests. The requested URL identifies the data to be operated on, and the HTTP method identifies the operation that is to be performed.

 

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22) When should you use an attribute versus an element?

 

Ans. An attribute is used when we are decorating an existing element with new functionality.

An element is used when we are creating a component that is in control of the template.

 

23) What is DDO (Directive Definition Object)?

 

Ans. DDO is an object used while creating a custom directive.

 

24) What is the Provider Method in AngularJS?

 

Ans. The Module.provider method allows to take more control over the way that a service object is created or configured.

 

25) What are the attributes which can be used during the creation of a new AngularJS Directives?

 

Ans. Restrict, Template URL, Template, Replace, Transclude, Scope, Require, Controller, Link and Compile.

These are some of the popular questions asked in AngularJS interviews. Always be prepared to answer all types of questions — technical skills, interpersonal, leadership or methodology. If you are someone who has recently started your career in web development, you can always get certified in one of the technical courses like AngularJS to get the requisite coding skills and methodologies.

 

About the Author

Hasibuddin Ahmed

Hasibuddin Ahmed

Hasib is a professional writer associated with learning.naukri.com. He has written a number of articles related to technology, marketing, and career on various blogs and websites. As an amateur career guru, he often imparts nuggets of knowledge related to leadership and motivation. He is also an avid reader and passionate about the beautiful game of football.