AngularJs Important Interview Questions and Answers

AngularJS is a framework with a structural format for dynamic web applications. It will help you to use HTML as your template language and let you expand HTML’s syntax to articulate your application components briefly and clearly. Angular JS is an efficient framework which can create RIA (Rich Internet Application).

Angular JS is famous among developers as it provides developers with options to write client-side applications by using JavaScript in a clean MVC (Model View Controller) way. Taking AngularJS Training either online or offline is one of the smart things to do now as it has been developed by one of the biggest technology giants Google. If you still haven't used Angular, then you must wonder why people say JavaScript is the most flexible language in the world. It helps to develop a maintainable architecture that is easy to test at the client-end. So, don’t miss out on anything and place your footstep into the Angular field and prepare yourself with the help of the AngularJs Interview question answer to crack the interview.

1. Does AngularJS support MVC or MVVM pattern?

AngularJS is an MVW framework where M stands for Model, V for the view and W for Whatever. It means you can follow either MVC or MVVM or MVP pattern since W stands for whatever you like.

2. What is ViewModel?

A ViewModel is an object that provides specific data and methods to maintain specific views. Basically, it is a $scope object which lives within your AngularJS app's controller. A ViewModel is associated with an HTML element with the ng-model and ng-bind directives.

3. Why are we using AngularJS?

We already know that AngularJS works on the MV* pattern. (where * can be C(controller) or VM (view model)). It enables us to create testable, well-structured, and maintainable front-end applications.Here are the reasons for using AngularJS:

It assists anyone to better organize web applications or web apps.
It also assists to make well-organized and responsive web applications that are more readable and expansive.
Two way data binding approach is used. This approach assists us so that any modifications in the model would be updated view and vice-versa; no need to make any modification on events or DOM.
AngularJS supports services and dependency injection that we can effortlessly inject into a controller and offers some utility code according to our requirements.
AngularJS allows you to make your own directive that allows reusable components to be utilized as per your requirement.

4. How to share data or state between AngularJS controllers?

There are multiple ways to share data or state between AngularJS controllers. The most commonly used ways are Scope, Service, Factory, and Providers.

5. What is $scope in AngularJS?

In AngularJS, $scope is an object that refers to an application model. In simple terms, it is a special JavaScript object which binds the view (DOM element) and the controller. The $scope object helps to access model data in the controller. Since the AngularJS supports MV* pattern, this object turns out to be the model of MV*.

It is important to note that both controller and View gain access to the scope object. Moreover, it can be utilized for communication between controller and view. Both functions and data are present in this object. Each AngularJS application contains a $rootScope which is the topmost scope made on the DOM element that comprises the ng-app directive. Furthermore, it can watch expressions and transmit events.

6. What is View in AngularJS?

The view is responsible for presenting your model data to the end-user. A view contains HTML markup including AngularJS directives, attributes, and expression which AngularJS parse and compiled with HTML to generate the dynamic view.

7. What are Expressions in AngularJS?

AngularJS expressions are looks similar to JavaScript expressions, which you put inside the HTML templates by using double braces such as {{expression}}. AngularJS evaluates the expressions and dynamically insert the result to a web page. Like JavaScript expressions, AngularJS expressions can have literals, variables, and operators. There are some valid AngularJS expressions :

Also Read: Top Basic and Advanced Node.js Interview

8. What is Databinding in AngularJS?

Databinding is a mechanism to bind data or events with your HTML elements. Before Databinding, you have to manipulate or update the DOM elements and attributes to update model changes. AngularJS Databinding handles it nicely with the help of following the Data binding mechanism.

One-Way Databinding
Two-Way Databinding

9. Explain Two-way Databinding in AngularJS?

Two-way data binding is the most popular feature of AngularJS. It is used to sync the data between model and view i.e. any change in the model will update the view and vice versa. The two-way data-binding, you can use only with form input elements using ng-model directive. It can't be used with other elements like span, div, para, etc. which don't accept any input from the user.

Two-Way Databinding Example--

<div ng-controller="myCtrl"> <label>Full Name (two-way binding): <input type="text" ng-model="name" /></label> <strong>Your Full Name (normal binding):</strong> {{name}} </div> <script> var app = angular.module('app', \\\[\\\]); app.controller("myCtrl", function ($scope) { $scope.name = "Mohan Chauhan" }) </script>

10. What is One-way Databinding in AngularJS?

AngularJS 1.3 came with one new data-binding called as One-way data-binding. For one-way data-binding, double colon (::) is used as data-binding expression syntax.

One-Way data binding Example--

<strong>Your Full Name (one-way binding):</strong> {{::name}}<br />

<strong>Your Full Name (normal binding):</strong> {{name}}

</div>

11. What are Directives in AngularJS?

AngularJS directives combine template markups (HTML attributes or elements, or CSS classes) and supporting JavaScript code to extend the power of existing HTML. The supporting JavaScript code defines the AngularJS template markup behaviour.In fact, AngularJS directives extend the HTML vocabulary by adding new attributes to manipulate HTML elements in an easy way. AngularJS supports various built-in directives like as ng-app, ng-controller, ng-repeat, ng-model, etc.

12. What is the use of ng-app, ng-init and ng-model directives?

The main use of ng-app, ng-init and ng-model directives areas follow :

ng-app: This directive is used to bootstrap the angular app.
ng-init: This directive is used to initialize data to AngularJS models.
ng-model :This directive is used to bind the data with form elements like input, select, text area etc.

13. What are different ways to invoke a directive?

There are four methods to invoke a directive in your angular app which is equivalent.

Methods Syntax--

As an attribute - <span my-directive></span>

As a class - <span class="my-directive: expression;"></span>

As an element - <my-directive></my-directive>

As a comment -

Also Read: Tips to Prepare for Angular JS Interview

14. What are restrict options in the directive?

The restrict option in an angular directive is used to specify how a directive will be invoked in your angular app i.e. as an attribute, class, element or comment. There are four valid options for restricting:

'A' (Attribute) - <span my-directive></span>

'C' (Class) - <span class="my-directive:expression;"></span>

'E' (Element) - <my-directive></my-directive>

'M' (Comment) -

15. What are the Filters in AngularJS?

Filters are used to transform data before displaying it to the user. Filters are used in templates, controllers, services, and directives for data transformation. AngularJS supports various built-in filters like currency, date, number, orderby, lowercase, uppercase, etc. Even, you can create a custom filter.

Filter Syntax--

Filter Example--

How Do You Prepare for an Angular Interview?

To prepare for an Angular interview, you should be aware of the latest standards and practices of various aspects of web development processes. This includes knowing TypeScript, JavaScript, HTML, and the application of these skills.

You also want to do research on the particular company you are applying for. This will give you a sense of what they expect, and you can prepare accordingly.

Don’t forget that actual coding and building is also very important. You should be ready to demonstrate your knowledge, and that is best practiced through hands-on work. You can look up Angular coding questions to help you practice.

Are these questions also relevant to Angular interview Questions?

Yes, these questions are helpful while preparing for the AngularJS interview. Angular is the top programming language and is used by most web developers. You need to be confident while giving the Angular interview. Also, if you’re asked a question you don’t know the answer to, a simple “That’s a good question, I’d have to get back to you on that one,” is better than giving some random non-answer and adding unnecessary details.

Candidates that are straightforward and honest are preferred over those pretending to be know-it-alls!

Further, don’t disburse your personal details until asked for. The interviewer is more interested in knowing you as a technical person.

So, all the very best! Do let us know the Angular questions you faced in the interview that are not covered here so that we can add those here for the benefit of the Angular community.