AngularJS Interview Questions and Answers

AngularJS is an open-source and java based front-end framework. It is maintained by Google and by the community of individuals and corporations to approach the challenges which get created while developing the single-page applications. The aim of AngularJS is to simplify the development and also the testing of thJavaese single-page applications. AngularJs is written in Javascript.

Development History:- AngularJS was developed in the year 2009 by Miško Hevery at Brat Tech LLC. It was developed as the software behind an online JSON storage service.

The websites of Wolfram Alpha, NBC, Intel, ABC News have used AngularJS. The first stable version of AngularJs was released on October 20, 2010.

Do you want to get success in the AngularJS Interview Questions? Continue Reading!!!

Latest Version:- The latest version of AngularJS 1.7.8 got released on 11th March 2019.

Advantages of AngularJS

  • AngularJS provides the ability to create a Single-Page Application which is easy to maintain.
  • AngularJS gives the user an easy and responsive experience by providing the data binding capability to HTML
  • The code of AngularJS is unit testable.
  • AngularJS uses dependency injection and it also makes use of separation of concerns.
  • AngularJS gives reusable components.
  • The developer writes less code and also gets more functionality
  • In AngularJS, views are the pure HTML pages, and controllers which are written in JavaScript do the business processing
  • Application created using AngularJS can run on all the major browsers and smartphones and even Android and iOS-based phones/tablets.

Our collection of questions related to AngularJS will be answered in the AngularJS interview questions mentioned below.

Ques 1. Explain about AngularJS

AngularJS is an open-source framework which is used to create high-performance single-page applications and websites. The aim of AngularJS is to simplify the development and also the testing of these single-page applications. AngularJS allows the developer to use HTML as the template language and enables the developer to extend HTML’s syntax to express the components of the application clearly.

Ques 2.Who designed AngularJS?

AngularJS framework was designed by Adam Abrons and Misko Hevery. The front-end framework is maintained by Google.

Ques 3. Explain the general features of AngularJS?

Some of the features of AngularJS are?:-

• It provides options to the developers for writing the client side applications using  JavaScript in an MVC (Model View Controller)

• It is a cost-efficient framework for creating the RIA (Rich Internet Applications)

• It automatically manages JavaScript code appropriate for every browser since the application which is written are cross-browser compliant.

         • It is an open-source Framework

         • AngularJS is easy to manipulate, implement and access

         • An application written in AngularJS use less codes as compared to applications written in

Javascript.

         • It supports TDD (test-driven development approach)

         • AngularJS makes HTML easy to maintain and spontaneous.

         • Unit Testing

This is the best AngularJS Interview Question particularly when you are an experienced candidate.

Ques 4.What are the core features of AngularJS?

The core features of AngularJS are:-

  • Data-binding − Automatic synchronisation of data between the model and the view components.
  •  Scope − They act as a gum between the controller and a view.
  • Controller − Controllers are the JavaScript functions that are bound to a specific scope.
  • Services − AngularJS has many built-in services like $http in order to make XML Http Requests.
  • Filters − Filters choose a subset of items from an array and then it returns a new array.
  • Directives −  AngularJS has actually built-in directives like ngBind, ngModel and many more. Directives are actually markers on Document Object Model(DOM) elements like elements, CSS, attributes etc. Directives are used for creating custom HTML tags which serves as a new custom widget.
  • Templates − Templates are the rendered view having the information from the model and also the controller. Templates can be a single file (like index.html) or can be multiple views in a single page using the partials.
  • Routing − Routing is a concept of switching the views.
  •  Model View Whatever − It is basically a design pattern which is used for dividing an application into three parts which are Model, View, and Controller. Each part have distinct responsibilities.
  • Deep Linking − For bookmarking the URL deep linking allows encoding the state of the application in the URL. After this, the application can be restored from the URL to the same state.
  • Dependency Injection − Dependency injection subsystem supports the developer to easily create, understand, and test the applications. Dependency injection subsystem is built-in in AngularJS.

This is one of the most asked AngularJS interview questions.

Ques 5. Can you share the disadvantages of AngularJS?

The two disadvantages of AngularJS are:-

  • AngularJS being a JavaScript only framework applications which are written in AngularJS are not secured. Authentication and Authorisation is must from the server side to keep the application secure
  • If the application user disables the JavaScript then the user will only see the basic page.As a result AngularJs is not degradable.

Ques 6. Can you explain about Data-binding in AngularJS?

Data binding is basically an automated synchronization of the data which is done between the view and model components. Data binding allows you to consider the model components as a single source of truth in the applications. The view component acts as a projection of the model. When the model changes then the view reflects the change and vice-versa.

Following are the two ways in which data-binding is done:-

            • Data mining in a classical template systems

            • Data binding in an angular templates

Ques 7. What is the role of controllers in AngularJS?

Controllers in AngularJS are the JavaScript functions which are bound to a specific scope. Controllers are the premier actors in an AngularJS framework and they carry functions to run on data and decide which view has to be updated to display the updated model based data. In other words, we can say that controller gives the data and logic to HTML user interface and controls the flow of data from the server to the HTML user interface.

Ques 8. What are the three core directives of AngularJS?

The three core directives of AngularJS are as follows:-

  • ng-app − ng-app directive defines and links an application of AngularJS to the HTML.
  • ng-model − ng-model directive binds the values of the data of AngularJS application to the input controls of HTML.
  • ng-bind − ng-bind directive binds the data of AngularJS application to the HTML tags.

Ques 9. Can you explain the ways to communicate between modules of the application by using core AngularJS functionality?

The ways to communicate between modules of the application by using core AngularJS functionality are:-

  • Using the services
  • Using events
  • By assigning models on $rootScope
  •  Directly between controllers, using $parent, $$nextSibling, $$childHead and many more
  •  Directly between controllers, using ControllerAs, or any other forms of inheritance

Ques 10. What is a Model View Controller ( MVC ) in AngularJS?

Model View Controller is a software design pattern which is used for developing web applications. An MVC pattern has three parts which are as follows:-

  • Model − Model is the lowest level of the pattern which is responsible for data maintenance.
  • View − View is accountable for showing all the data or a part of the data to the user.
  • Controller − Controller is a software Code which handles the interactions between the Model and the View.

Ques 11. The two similar “destroy” events are fired when a scope is terminated. What are these destroy events used for and why the two events are fired?

When a scope is terminated then the first destroy “$destroy” event which is fired is an AngularJS event and the second destroy event “$destroy” which is fired is a jqLite or jQuery event. The AngularJS event can be utilised by an AngularJS scope where they are approachable, like in controllers or in link functions. The jqLite or jQuery event is called when a node is removed, which may occur without scope teardown.dd

Ques 12. How AngularJs can be integrated with HTML?

AngularJS is a pure JavaScript based library ,therefore, it integrates very easily with HTML.

Step 1 − Include an angularJS javascript library in the HTML page

<head>

  <script src = https://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js”></script>

</head>

Step 2 − Now point to an AngularJS app

To tell which part of the HTML contains the AngularJS app ng-app attribute is added to the root HTML element of the AngularJS app.

It can be added either to HTML element or to the body element as written below

<body ng-app = “myapp”>

</body>

Note: Go through this Question very thoroughly as this is one of the most important AngularJS interview questions.

Ques 13. What is the role of AngularJS expressions?

The role of  AngularJS expressions is to bind application data to the HTML. Expressions are written inside the double braces {{ expression}}. Expressions behave exactly like ng-bind directives. AngularJS application expressions are completely JavaScript expressions and they output the data where they are used.

Ques 14. What is the difference between the Angular expressions and JavaScript expressions?

S No.  Angular expressions JavaScript expressions
1 The Angular expressions are evaluated against a scope object The JavaScript expressions are evaluated against the global window.
2 Loops, exceptions or conditionals cannot be used in Angular expressions Loops, exceptions or conditionals can be used in JavaScript expressions
3 Data can be formatted before displaying by using filter Data cannot be formatted before displaying by using filter

Ques 15. What is the difference between the compile function and link function in AngularJS?

S No. Compile function Link function
1 It is used to collect the directive and for template DOM Manipulation It is used for instance DOM manipulation and for registering DOM listeners. Link function is executed after the cloning of the template.

Ques 16. What do you mean by the module in AngularJS?

Modules in AngularJS is used to keep the code clean and to separate the logic such as filters, services, controller, directives and many more. The module is defined in separate js files and the modules are named as per the module.js file.

Ques 17. How can you create an Application module?

Application module is used to initialize an application with a controller

var mainApp = angular.module(“mainApp”, []);

Here, mainapp application is declared using the angular.module

Ques 18. What do you mean by AngularJS routes?

AngularJS routes enable you to create separate URLs for separate content in the application. This action enables the user to bookmark the URLs to particular content. Bookmarkable URL is known as a route.

Ques 19. What are the steps in which the Compilation process of the HTML occurs?

Compilation process of the HTML process occurs in the following steps:-

  • Step 1:- Firstly the HTML is parsed into DOM using the standard browser API.
  • Step 2:- Compilation of the DOM is performed using the call to the $compile () method. This method traverses the DOM and then matches the directives.
  • Step 3:- Now lastly link the template with a scope by calling the linking function which was returned from the previous step

This is one of the most asked questions in AngularJS interview questions

Ques 20. Name the different types of derivatives in AngularJS?

There are three types of derivatives:-

  • Element directives
  • Attribute directives
  • CSS class directives
  • Comment directives

Ques 21. What is the use of the factory method in AngularJS?

Factory method in AngularJS is used for creating a directive. The factory method is invoked when for the first time compiler matches the directive. Factory method can be invoked using $injector.invoke.

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

Result: When factoryName as an injectable argument is declared then the value is provided which is returned by invoking the function reference which is passed to module.factory.

Ques 22. What the role of internationalization in AngularJS?

Internationalization is a way through which locale-specific information on a website can be shown. AngularJS assist an inbuilt internationalization for three different types of filters which are currency, date and numbers. To apply internalization, the corresponding js according to the locale of the country has to be incorporated. Internationalization handles the locale of the browser by default.

Ques 23. What do you mean by bootstrapping in AngularJS?

Bootstrapping is for initializing or starting the Angular app. AngularJS supports two types of bootstrapping:-Automatic and Manual bootstrapping.

Automatic Bootstrapping: Automatic Bootstrapping is done by adding an ng-app directive to the root of the application.

Manual Bootstrapping: Manual bootstrapping provides you control on how to initialize and when to initialize the angular App. Manual bootstrapping is useful where the user wants to execute any other operation before Angular wakes up and compile the page.

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