Top AngularJS Interview Questions and Answers (Freshers & Experienced)

Basic AngularJS Interview Questions and Answers

Here we have categorized a set of basic AngularJS interview questions and answers for your convenience.

1. What is AngularJS? Explain its important features in simple words.

AngularJS is considered one of the most popularly used JavaScript-based web frameworks that was primarily designed to work on single-page applications, along with certain lines of code. 

One of the main reasons why it is used is to design specific client- or user-side logic through the integration of the abilities of MVC architecture with JavaScript. 

Some of its important features are 

- Controllers: In AngularJS, controllers are JavaScript functions that help manage an application's logic. This functions by updating user data and considering triggering behaviors.

- Apps built using AngularJS are easy to run tests on. This, in turn, allows users to easily check the functionality issues before production.

AngularJS also has certain specific built-in filters that are very helpful when it comes to sorting, formatting, as well as limiting results. 

On top of that, you can create your custom filters to reduce repetitive filtering, especially when working with arrays or applying conditions to display data.

2. What is meant by Directives?

In AngularJS, directives serve a key function that helps in driving the core functionalities of the framework. They are the most powerful features that add to HTML elements (like tags, attributes, classes, or even comments). They focus on extending the behavior or adding some kind of new functionality. 

Directives allow you to design custom HTML elements that behave like interactive components or widgets.

Along with this, directives guide AngularJS on how to process or transform elements in the DOM. Some really frequently used built-in directives are -  ngApp, ngModel, ngRepeat, ngClass, ngBind, and ngInit. One critical factor that we must remember is that each of these directives serves a different purpose, from binding data to initializing application components.

3. What method do you use to link AngularJS with an HTML document?

There are many options to link AngularJS within an HTML document. For this, the AngularJS library should be included in the HTML code file using a <!–Other libraries–> <!–ng-app attribute to bootstrap the AngularJS application–><!–Web page elements–>

4. Explain the concept of scope in AngularJS.

Scope is a very essential JavaScript object that has the important function of binding the views (HTML) with the controller (JavaScript). Here, the role of the controller is to set the properties on the scope while the view binds references to display data.

 This is among the most important Angular interview questions that can be quite expected during the interview process. 

5. Explain the AngularJS data binding process.

The data binding process in AngularJS is a mechanism that keeps the working model and the view in sync. This guarantees that all the changes of one section would instantly be reflected in the other in sync. 

The two types of data binding are  

One-way data binding is about the data flows in a single direction, and any modifications to the data model are instantly and automatically reflected in the application's interface.

And with this, certain specific changes won’t really have an impact on the model. This type of binding is generally done using the ng-bind directive.

With two-way data binding, information flows in both directions, meaning any updates to the model are immediately shown in the view, and user inputs in the view are instantly applied to the model. The ng-model directive is frequently employed to implement this functionality.

AngularJS Technical Questions and Answers

Here we have categorized a set of AngularJS technical questions and answers for your convenience.

6. What distinguishes an AngularJS module from an AngularJS component? 

An AngularJS module acts as a container that helps organize various components of an application, including directives, filters, and services.

On the other hand, an AngularJS component is a very special kind of directive that is specifically developed to build reusable elements of UI with a much simpler configuration, which is able to promote a component-based architecture.

7. What is the requirement of Interpolation in AngularJS?

Interpolation allows for a very powerful connection between application data and the user interface, and during this process of compilation, AngularJS tries to analyze the markup to identify and process these embedded expressions. Along with this, it also uses a certain built-in $interpolate service for detecting specific embedded expressions and establishing specific watchers when it comes to monitoring the various modifications so that the displayed data is able to stay updated automatically. 

8. What is the difference between directives ng-if and ng-show?

When the condition specified in the ng-if directive results in false, the corresponding DOM element will never be created. With this, the scope associated with that element is also removed. But when the condition in the ng-show directive is shown as false, the DOM element still remains.  And on the other hand,  if the condition in the ng-show directive is false, the DOM element remains. But it is hidden from view by applying the ng-hide class, which sets its display to "none." 

This is again one of the most expected AngularJS interview questions. 

9. What do you understand by the Digest cycle in AngularJS?

The most important cycle needed in the data binding process is known as the digest cycle or digest phase.

It does the function of comparing the older version of a model with the newer one and as soon as any change or modification happens in the scope model during the comparison, the model's watchers are finally employed, and the digest cycle continues to run repeatedly until no further changes are detected in the scope model. 

10 How would you describe the following code snippet? 

The following AngularJS code snippet defines a dropdown menu using the ng-options directive:

html

What It Does:

- This directive tries to generate the list of elements for the dropdown.

- It also iterates over the employeeList array, where each item is assumed to be an object representing an employee.

- It also displays the name property as the visible text in the dropdown for each employee in the list. 

Now, since we have read about the AngularJS technical questions and answers, let's go through some AngularJS Interview Questions specifically for experienced developers.

AngularJS Interview Questions for Experienced Developers

Here we have categorised a set of AngularJS Interview Questions for Experienced Developers for your convenience. 

11. Explain Dependency injection along with its benefits.

Dependency Injection (DI) is a design pattern in software engineering that helps to accomplish the Inversion of Control (IoC) by dissociating the development of certain dependencies from those specific classes that use them. 

Another important factor to consider is that these dependencies are also “injected” into the class through a foreign source, mostly by the property injection or the constructor. 

12. Explain Single Page Application and how it can be used in AngularJS.

A Single Page Application (SPA) is usually considered an approach in design where the entire application runs within a single main page without needing to reload the whole page from the server for every interaction. Another important thing we must keep in mind about these SPAs is that, instead of using the traditional postbacks, only the necessary content is loaded and injected into a central layout or shell page. 

13. What is the requirement of $watch in AngularJS?

The $watch function is mainly used to monitor certain changes in a variable or expression on the $scope object. Another important thing is that $watch in AngularJS gives the opportunity to run a designated function automatically whenever the observed value is updated. 

Responding to Model Updates- When a change in a model variable should trigger some additional logic, like a side effect or a more involved computation that standard AngularJS directives don’t cover, you can use $watch to monitor the variable and run custom code when it changes.

Working with Third-Party Libraries - When you use external libraries that update data outside of AngularJS’s digest cycle, $watch can be used alongside $apply to make sure AngularJS detects those changes and properly refreshes the view to reflect the updated data.

14. What is meant by  $rootScope in an AngularJS Application?

In AngularJS, the $rootScope refers to the primary scope object tied to the DOM element containing the ng-app directive, responsible for bootstrapping the application. The $rootScope object is accessible across the whole AngularJS application. There can be only one $rootScope object throughout the entire application. Any other scope objects in the application are considered child scopes of the $rootScope.

During the bootstrapping of an AngularJS application, the $rootScope is the scope object formed on the DOM element where the ng-app directive is placed. 

This is also available in the whole AngularJS application, and another important thing for us to take into consideration is that only one $rootScope object will remain in the complete programme.

Along with this, the other scope objects that are present are called the child scopes of the $rootScope. 

15. What do services mean in the context of AngularJS?

Services are known as the single objects that do the work for which they were specifically developed. These interact with each other and are also linked through the Dependency Injection principle, which helps the framework when it comes to sharing the code as well as structuring the application. 

Another important aspect related to these services is that they are available with various built-in services and custom services, which are majorly popular among various coders and programming enthusiasts, and are also assisted by AngularJS. 

Some tips to prepare for AngularJS interview questions 

Here are some easy and efficient tips for you to start your preparation for AngularJS interview questions

1. Master the basic principles
2. Refer to the previous years’ common AngularJS interview questions
3. Highlighting the practical skills you have gained through certain projects
4. efficiently showcasing your problem-solving skills.

Thus, these simple tips will guide you to prepare effectively for the AngularJS interview questions. 

FAQs (Frequently Asked AngularJS Interview Questions)

1. What are some easy ways to prepare for the AngularJS interview questions?

Ans - You can take on a very strategic approach in your preparation for the AngularJS interview so that none of the important topics are missed from your side. 

You must prepare for those important behavioral- and situational-based questions, along with practicing coding, to build your skills in this sphere. 

2. Is it difficult to prepare for the AngularJS interview questions?

Preparing for the AngularJS Interview Questions can be a bit challenging for some individuals since Angular often focuses on a very broad learning phase due to its complicated elements, such as components, modules, etc. 

3. Is it possible to master AngularJS interview questions in a week?

It takes around two to three months to prepare for the AngularJS interview questions with constant dedication and practice of about three hours each day.  

Conclusion

This list of AngularJS interview questions will therefore be very beneficial for you to prepare for your interview and pass it in a successful manner. 

Through these AngularJS interview questions and answers for beginners as well as for the experienced and advanced professionals, we have tried to categorise the various questions, so that you are able to understand the concepts smoothly and that the topics are grasped by you in a very thorough way. 

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