Top 50 AngularJS Interview Questions and Answers for Freshers and Experienced

AngularJS Interview Questions and Answers

AngularJs is the most required web development frameworks across the world. While you are thinking of starting your career in AngularJS, you get tensed to think that how will you clear an interview round?

In every AngularJS interview, the interviewee has to face a lot of questions to get a job. If you are also going through this cycle, then you have to face a lot of questions to get a position among other interviewees.

To make you stand confidently in the AngularJS interview, you have gathered 50 questions that are mostly targeted by the interviewer. Thus, to get a job in AngularJS, you have to read the following blog entirely, not once, but twice or thrice. We have covered questions and answers that can ask at the interview level. 

Moreover, if you are either fresh or experienced in AngularJS, the following guide will be perfect for you. Thus, read it to the end to clear your interview with ease: 

Most Frequently asked 50 AngularJS Interview Questions and Answers for fresher and experienced interviewees:

1. What is AngularJS?

Whenever there is a need to make worthwhile and extensible web applications, then AngularJs is used. It is also a JavaScript framework. Even a single web application is created by it. With this framework, we can use HTML as our template language, and it also enables us to extend HTML’s syntax to show our applications’ components distinctly. 

To execute AngularJS, we use HTML and Javascript. Thus, we don’t have to depend on others to complete the work. Moreover, AngularJs is also well-recommended for SPA, i.e., single-page applications to bind the objects of JavaScript with HTML UI elements. 

2. Tell about the features of AngularJS.

Answer: The features that are the part of AngularJS are:

  • Services
  • View
  • Scope
  • Directives
  • Filters
  • Controller
  • Testable
  • Services, and 
  • Data Binding

3. What is Data Binding?

Answer: To automatically blend the data between the model components and view, data binding exclusively used.

4. What is the difference between AngularJs and JavaScript expressions?

Answer: The terms AngularJs and JavaScript expressions differ in many ways. For instance:

  • In AngularJs, there is no need to use loops, condition iterations, and exceptions, while all these are needed to use in JavaSript expressions. 
  • No filter is supported in JavaScript, while supports in AngularJs.
  • AngularJs expressions can be written in HTML, while this is not possible in JavaScript.
  • In the case of AngularJs, the evaluation used to forgive to undefined or null while in case of JavaScript expression, all undefined properties result in ReferenceError or TypeError.

5. What are the advantages of the AngularJS framework?

Answer: The AngularJS framework offers many advantages for web development like:

  • It supports MVC pattern
  • It supports animations along with client-server communication
  • It provides two-way data binding that is not possible in other cases.
  • It supports angular and static template
  • It supports dependency injection
  • It supports full rest services
  • It applies animations
  • It offers to add custom directives
  • It supports event Handlers

6. What are the services in AngularJS?

Answer: When there is a need to carry out a particular task in AngularJs, then services are used as singleton functions or objects. These functions are also known as directives, controllers, and filters.

7. Difference between SessionStorage, Cookies, and LocalStorage

Answer: 

A: SessionStorage: In session storage, data stored in a specific session, and it will be lost in a case the browser tab closed for a particular time or session. In session storage, it stores 5MB maximum size of data. 

B: Cookies: Cookies help to store that data that needs to send back to the server by request. The usage of cookies relies on the duration and typeset from either the client-side or the server size. In cookies, it stores 4MB, the maximum size of data.

C: LocalStorage: In local storage, there is no expiration date for storing of data. In this case, it is possible to clear the data only either with JavaScript or the browser cache. In local storage, it stores the maximum size of data as compared to session storage and cookies.

8. What is the main difference between $scope and scope?

Answer: The scope is used in AngularJS for linking between the controller (like JS) and view (like HTML), while the $scope used to accomplish dependency injection.

9. What is the primary role of $routeProvider in AngularJS? 

Answer: When there is a need to navigate between different links or pages without individually loading the link or data when a user clicks on a link, then $routeProvider is required. To configure the routeProvider, we use the ngRoute config() method. 

10. Where to implement the DOM manipulation in AngularJS?

Answer: To manipulate DOM can be done only in directives. It is not possible to exist in controllers’ services or any other way.

11. How are AngularJs prefixes $ and $$ used?

Answer: The term $ used in AngularJS for denoting angular core functionalities such as a parameter, a method, or a variable.

The term $$ used in AngularJS like a private variable to get saved from accidental code collision.

12. How to show that a scope variable should have one-time binding only?

Answer: In a case, we need to show one-time binding, then we have to use this sign ‘::’ in front of the scope.

13. Explain different types of data bindings are there in AngularJS?

Answer: The fact, AngularJS can support one-way and two-way binding.

One-way binding: In a case of one-way binding, there will be no dynamic change even if we change the data model.Two-way binding: In a matter of two-way binding, there will be a dynamic change when we change the data model.

14. What makes AngularJS better? 

Answer: It does not have any initialization code: We can bootstrap our application quickly with AngularJs by using its services.

  • It dominates HTML DOM programmatically: It is not possible to manipulate the DOM in the AngularJs.
  • It does not register callbacks: In AngularJs, there is no need to register callbacks. It assists in making the code easy to process and also debugging the errors.
  • It helps to transfer the information to and from the UI: With AngularJs, it becomes feasible to delete the boilerplate such as displaying validation errors, validating the form, and much more.

15. What is the SPA (Single page application) in AngularJs?

Answer: Single page application is a web application that used to load a single HTML page. It also helps to update the page to make the users connect with the application. With the help of HTML and AJAX, it is possible by the SPA to create responsively, and fluid web app without entertaining invariant page reloads. In this way, one can able to make responsive UI without taking the assistance of page flicker.

16. What are the directive scopes in AngularJs?

Answer: In AngularJs, there is a use of three directive scopes. These are:

  • Parent scope: Parent scope is also known as a default scope. Whatever amendment is made in the directive by us, it comes from the parent scope and views in the parent scope.
  • Child scope: Child scope is a nested scope that takes property from the parent scope. Whenever a property or function not connected with the parent scope directive, then there is a creation of a new child scope.
  • Isolated scope: When there is a need to establish a self-contained directive, then the isolated scope is used. Moreover, this scope only used for internal and private use. It means that it never has much property of the parent scope. Also, the isolated scope is reusable. 

17. What are the binding directives in AngularJs?

Answer: We use five binding directives in AngularJs. These are:

  • ng-bind
  • ng-non-bindable
  • ng-bind-HTML
  • ng-bind-template
  • ng-model

18. Explain ng-bind and ng-bind-HTML directives.

Answer: ng-bind directives: Whenever there is a need to replace the content of the HTML element to the value of the allotted expression or variable, then we use ng-bind directives. Even, we can replace the content of the HTML element by amending the value of the expression or variable. Moreover, ng-bind directives are like ({{expression}}) while syntax is 

//<ANY ELEMENT ng-bind=”expression”> </ANY ELEMENT>//

ng-bind-HTML directives: Whenever there is a need to bind the contents to the HTML element is a safe and reliable way, then we use ng-bind-HTML directives. We use a $sanitize service to sanitize the content to integrate it into an HTML element. Moreover, to perform this service, ‘angular-sanitize.js’ needs to add in our application. //<ANY ELEMENT ng-bind-html=” expression “> </ANY ELEMENT>// is a syntax used in ng-bind-HTML directives.

19. How to share the data between controllers in AngularJs?

Answer: Whenever there is a need to share data between controllers in AngularJs, then there is a need to create a service first. This service used to transfer the data between controllers in AngularJs in simple, reliable, and quick way. While sharing the data, we can even use the next sibling and $parent.

20. What are filters in AngularJs?

Answer: A significant task done by filters in AngularJs is to modifying the data, thereby it can integrate into a directive or expression with the usage of a pipe character. It is used in applying filters. It is used as an angular symbol of a pipe. (|) or this is a sign that is used as a symbol. A filter is a module that is provided by the AngularJs. Right now, there are nine components of a filter that can be taken from the AngularJs. For instance: Filter, json, limitTo, currency, etc.

21. What is the ng-App directive in AngularJs?

Answer: The ng-App directive in AngularJs is used to specify the AngularJs Application. It is used to call the root element of an AngularJs app. Also, it can be stored near <body> or <html> tag. It is possible to show any number of ng-app directives in the HTML document. However, it is possible to bootstrap only one application automatically. Moreover, the other applications are needed to bootstrap manually. 

For Example:

//<div ng-app=””>

<p>My first expression: {{178 + 133}} </p>

</div>//

22. What is string interpolation in Angular.js?

Answer: In Angualr.js, there is the use of compiler in the complication process to identify the text and elements by using the interpolate service to notify if they have embedded expressions or not. 

23. What are the steps used in the compilation process of HTML?

Answer: To parse the HTML into DOM, we use standard browser API.

After that, to perform a compilation of the DOM, a call to the $compile () method is used. With this method, the DOM is crossed and also matched the directives.

Finally, the template is linked with the scope with the assistance of the link function that was returned in the last step.

24. What is the injector?

Answer: An injector is used, when there is a need to read object instances like said by the provider, instantiate types, and load modules. It is also a service locator. Additionally, it is a single injector accordingly angular application used to find out an object as per its name.

25. What are the characteristics of ‘Scope’?

Answer: 

  • It is used to ensure the context against which expressions are analyzed.
  • It has inherited property that is taken from its parent scope. It also offers access to shared model properties. Moreover, it also nested to separate application parts.
  • It generates any model amendments via the system.
  • It is used to observe model mutations for APIs.

26. What is the difference between AngularJS and backbone.js?

Answer: AngularJS is used to integrate the functionality of 3rd party libraries. Besides, it also supports individual functionalities that are needed to create HTML5 Apps. However, in the case of backbone.js, all these tasks are done separately.

27. What is the main difference between link and compile in AngularJS?

Answer: Link function in Angular.js is used to register DOM listeners and also manipulate DOM. 

Compile function in Angular.js is used to template DOM manipulation. It also assembles all of the directives.

28. Who created Angular JS?

Answer: Adam Abrons and Misko Hevery initially developed it. After that, AngluarJs is developed by Google.

29. Explain all the steps to configure an Angular App (ng-app)

 Answer: There are specific points that need to consider to configure an Angular app:

  • First of all, the Angular module should be created
  • Then, a controller is assigned to the module
  • After that, the module is get linked with the HTML template by the assistance of the Angular App.
  • Finally, the HTML template will get linked to the controller with an ng-controller directive.

30. What do you mean, Angular Modules?

Answer: To write an angular code, we use the Angular application. We get this angular application from the Angular modules. These modules comprise the different components of an angular application. 

31. Explain ng-bind-template and ng-non-bindable.

Answer: Ng-non-bindable: It assists the AngularJs not integrating with the content of HTML element along with its child nodes. For example: //<ANY ELEMENT ng-non-bindable > </ANY ELEMENT>//

ng-bind-template: It is used to substitute the text content of the component by inserting of the template. It has made with multiple double curly markups. For Example: //<ANY ELEMENT ng-bind-template= ” {{expression1}} {{expression2}} … {{expression n}} “> </ANY ELEMENT>//

32. What is a controller in AngularJs?

Answer: A controller is used to create the initial state of the scope object and also adding behavior to the object. It is a JavaScript function that is integrated into a particular scope. Angular incorporates the new controller object and vaccinates the new scope like a dependency. Moreover, a controller never uses to share state or code across controllers. 

Controller is used in AngularJs as shown in the following:

//<Any ng-Controller=” expression”> 

</Any> 

<div ng-app=”mainApp” ng-controller=”SimpleController”> 

</div>//

33. What is the ng-repeat directive in AngularJs?

Answer: It offers a wide number of items and establishes DOM components. It continuously accesses the source of data to resending a template in return of an amendment. The syntax used in the ng-repeat directive in AngularJs:

//<table class=”table table-bordered”> 

    <tr ng-repeat=”student stuDetails”> 

<td>{{stu.name}} </td> 

<td> {{stu. grade}} </td> 

</tr> 

</table>//

34. What is ng-switch in AngularJs?

Answer: When there is a need to conditionally substitute the structure of DOM on a template that is entirely relied upon a scope-based expression, then ng-switch in AngularJs is used. Moreover, this directive is used to hide or reveal the HTML element by relying on the expression. The syntax used in ng-switch in AngularJs is:

//<element ng-switch=”expression”>

<element ng-switch-when=”value”></element>//

35. What do you mean by a double-click event in AngularJs?

Answer: When there is a need to exhibit the custom behavior on a double click event on the web page, then this event is used in AngularJs. It can be used as an element of the HTML element such as //<ANY_HTML_ELEMENT ng-dblclick=”{expression}”> 

</ANY_HTML_ELEMENT>//

36. What do you mean by ng-include and ng-click directives in AngularJs?

Answer: The term ng-include is needed to add distinct files on the main page while the ng-include directive adds HTML from an external file. The added content will be considered as child nodes of the particular element. Moreover, the added file should be placed on the similar domain like the document such as <div ng-include=”‘myFile.htm'”></div>. Moreover, ng-click is used in the case when we need to click on a bottom or when there is a need to perform an operation. The main purpose of it conveys AngularJs how to behave in case an HTML element is clicked. For example: //<button ng-click=”count = count + 1″ ng-init=”count=0″>OK</button>//

The above-written code is used for hiking up the count variable by 1 when the button gets clicked.

37. What is the difference between services and factory?

Answer: Whatever functions are used to return the objects are known as factories while constructor functions of the object are known as services that are used by a new keyword:

Syntax used in Service: module.service(`serviceName`, function

Syntax used in Factories: module.factory(`factoryName`, function

38. In a case, both factory and service are equivalent, then when should I use them?

Answer: The service provider is recommended to use with class while the factory provider is recommended to use within an object.

39. What is the difference between AngularJS and React.JS?

Answer: AngularJS: It is a TypeScript language that is based on the JS framework. It was released by Google in the year 2010. We don’t need to pay anything to use AngularJs as it is an entirely free framework that is used in Single Page Application (SPA) projects.

React.JS: It is a javascript library. It was created by Facebook in the year 2013. It is used to build UI. We can use react components on the many pages; however, we can’t use it as a single page application.

40. Tell about ng-show, ng-if, and ng-hide.

Answer: ng-show directive: It is used to exhibit the HTML element in a case expression that becomes true. Moreover, when the expression results in false, then we hide the HTML element. 

Syntax used in ng-show directive is //<element ng-show=”expression”></element>//

The ng-if directive: It is used in the case of a clause that eliminates the HTML element only when expression results in false.

Syntax used in ng-if directive is //<element ng-if=”expression”></element>//

ng-hide directive: When the expression results in false, then ng-hide directive is used to hide the HTML.

Syntax used in ng-hide: //<element ng-hide=”expression”></element>//

41. What is the main difference between ngRoute and ui-router?

Answer: ngRoute: It is a module created by the AngularJs team. It is an element of the core angularJs framework. It is a URL based routing.

Ui-route: It was created by 3rd party community to eliminate the barriers of ngRoute. It is a state-based routing.

42. How can we set, get, and clear cookies in AngularJS?

Answer: It should be noted that AngularJs has a module that is known as ngCookies. Before injecting ngCookies, Angular cookies.js must be added to the application. 

  • Set Cookies: We use the Put method to set cookies in a key-value format like 
  1. $scope.username);
  • Get Cookies: We use the Get method to get cookies.
  • is used in Get cookies: $cookies.get(‘username’);
  • Clear Cookies. We use the “remove” method to remove cookies.

            Syntax is used in Clear cookies: $cookies.remove(‘username’);

43. Is AngularJS well-suited with all browsers?

Answer: Yup! We can use Angular JS with maximum browsers like Chrome, Opera, Safari, IE, Mozilla, Firefox, and more.

44. What do you mean by Event Handling?

Answer: It is an AngularJus. It is essential when users need to establish advance AngularJs applications.

45. What is the Factory method in AngularJs?

Answer: We use a factory method to deploy a module pattern in that we use a factory method to raise an object in favor of building models.

Syntax used in factory object: module.factory(‘factoryName’, function);

46. What are the AngularJs Global API?

Answer: When we want to perform tasks such as iterating objects, comparing objects, and converting data, then there is a need for a combination of a global JavaScript function that is known as AngularJs Global API.

47. What are the common API functions?

Answer: The common API functions are:

  • angular. Uppercase: to convert a string to uppercase string
  • angular. lowercase: to convert a string to lowercase string
  • angular. isNumber: The results will be true in a case, current reference is a number
  • angular. isString:  The results will be valid in a case; current reference is a string.

48. Are Nested Controllers possible or not in AngularJs?

Answer: Yup, We can use nested controllers in AngularJs as these are well-defined in a classified way used in case of a view.

49. What is the primary difference between AJAX and AngularJs?

Answer: AngularJS: It is a typescript language that is based on JavaScript. It is following the MVC pattern.

AJAX or Asynchronous JavaScript: It is used to send and receive responses from the server. In that case, no page is loaded.

50. Explain representational state transfer (REST) in AngularJS?

Answer: When we need to operate over the HTTP request, then REST is used. It is an API style. With the requested URL, it is possible to find out data needs to be operated while the HTTP method is used to find out the operations that need to perform. 

REST is used as a style of API, while RESTful is used to specify an API that is following the REST style.

Conclusion 

If you read the above 50 interview question and answers for AngularJs, then you will be able to cover the maximum part of your interview. You need to read each item thoroughly. These are adequate to clear the interview round. These are written simply. Thus even beginners can able to understand and learn it without any interruption. Therefore read these AngularJs interview questions and answers thoroughly.

All the best!

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