Top 10 Angular interview questions and answers for 2023

Are you a job seeker looking for an Angular job? Or, are you a recruiter trying to find an adept Angular developer? Whatever be your quest, these top Angular interview questions will help you in one way or another.

Last updated on Jan 16, 2023

Angular is an in-demand JavaScript framework. Developers with expertise in Angular are needed for developing web and other applications. However, because of the high demand, the competition is also high. This is why it is not easy to crack Angular interview questions. As an experienced Angular developer, Angular interview questions should be easy for you to answer, but as we all know, when engrossed in real work, we sometimes don’t pay attention to the terminology or some in-depth technical concepts. This list of Angular interview questions and answers will assist you in refreshing those concepts.

It doesn’t matter whether you are a recruiter or an Angular developer, you can use these Angular interview questions for the Angular interview.

Angular interview questions and answers


Name the modules that you must import to use [(ngModel)] and reactive forms.

FormsModule and Reactiveforms Module


Are AngularJS and Angular 2 similar?

Yes, they are similar as both are front-end frameworks that Google maintains. However, they are different as Angular 2 is not just an upgraded version of Angular JS. Angular 2 is a newly developed framework that has been written from scratch. So, if someone is looking to upgrade or change to Angular 2 from Angular JS, it will require rewriting the code.

In this or other Angular 2 interview questions, if you can use practical examples or past experience to answer the question, it will get you some brownie points.


Explain Transpiling in Angular.

When the source code of one programming language is converted into another, the process is called Transpiling. In Angular, this mostly refers to converting TypeScript into JavaScript. As a developer, you can write your Angular application’s code in TypeScript or Dart and then transpile it to JavaScript for running the application. This process is internal and automatic.

Angular interview questions like this help the interviewer understand the depth of your Angular development knowledge.


What do you mean by AOT compilation?

AOT is the abbreviated form of Ahead-of-time compilation. For Angular applications, this would refer to writing the application code and compiling it at build-time i.e. before the application runs in the browser. This is an alternative approach for Just-in-time compilation where the compilation of code is done just before running the application in the browser. Better application performance can be achieved with AOT compilation.

This type of Angular interview question judges your presence of mind and whether you know alternative approaches to different scenarios.


Mention some change detection strategies.

Default and OnPush are the two change detection strategies. If the default strategy is implemented in all the components, Angular performs a check on the whole tree irrespective of where the change took place. The OnPush detection strategy is used when the developer has to inform Angular that the performance improvement conditions will be followed. This informs Angular that the application’s component relies on the input alone and objects passed must be considered unchangeable. The Principle of mile automaton, in which the current state relies on the input values alone, is used for this purpose.

This is another popular type of Angular interview question where you must know different techniques and the difference between them.


Describe the Change Detection Mechanism.

A model with a view is synchronized using Change detection. Information flows unidirectionally in Angular even when the ng Model is used for implementing two-way binding. Ng Model works like syntactic sugar over a unidirectional flow. Change detection mechanism has a forward-only flow where it starts from the root component and ends at the last. The tree of components represents the architecture of any Angular application. Here, every component points towards the child component, but the reverse is not true, i.e. the child component does not point to the parent component. The need for a $digest loop is precluded because of the unidirectional flow.

Another type of Angular interview question that is often asked is about definitions or descriptions. It is better to include some prior experience when answering this type of Angular interview question. This would differentiate your answer from a textbook answer for an Angular interview question.


When your data model is updated outside of Zone, how do you update your view?

The following methods can be used to update the view:

  1. method will help update the view by running change detection on the complete component tree.
  2. method can achieve the same by similarly running change detection on the whole tree. The run method calls tick internally, and the function that must be performed is taken by the parameter before the tick.
  3. ChangeDetectorRef.prototype.detectChanges method runs change detection on the present component and the children of the present component.


When is lazy loading of modules needed?

Lazy loading of modules is required when the code is to be broken into pieces. When an app is downloaded into the browser, the entire application code doesn’t load. When the transition to the route takes place with lazy loading, the lazy loading module loads the code into the browser.


Differentiate between unit testing and one-to-one testing. Mention a couple of testing tools for Angular applications.

When one needs to ascertain the proper functioning of isolated segments, unit testing is used to test these segments. On the other hand, when one wants to ensure that entire sets of components are working properly in sync and the application is working as expected, one can use one-to-one testing. User interaction simulations are often used in one-to-one tests to ensure that apps are functioning properly. Two good testing tools are Jasmine and Karma.


What are Core and Shared modules used for?

For all modules, components, etc. that needn’t occur in a single copy for the application, instead must be imported into different modules, there is a generic module called the Shared module. For storing services that must occur in a single copy in the whole application, a Core module is used. For example, when user authorization for data storage is needed, the user authorization appears as a core module.

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Wrapping up

The above Angular interview questions give you an overview of the technical aspect of the interview. The Angular interview process, however, will contain the technical Angular interview questions and questions based on a variety of soft skills. Soft-skill-based questions are essential to determine whether the Angular developer is a good fit for the team or is more of an individual worker. Adding these questions to the technical Angular interview questions helps the recruiter determine whether they should hire you as a permanent employee or offer you a freelance position.

If you are an Angular developer with some experience and are looking for a new job in a top US MNC, apply at Turing. If you are a recruiter hunting for top Angular developers to enhance your team, contact Turing.

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