Angular Interview Questions You Must Prepare for in 2023

Angular web developers are in huge demand. If you’re a developer preparing for a tech interview, it is crucial that you understand the type of Angular interview questions asked at top companies.

Angular is a component-based framework that’s used for building scalable web applications. In the world of modern application development, Angular is immensely popular thanks to its declarative templates, dependency injection, and end-to-end tooling that resolves the challenges faced by developers.

Even though there is no official Angular certification available, companies are keen on hiring developers who are well-versed with the Angular framework, especially because there are several iterations. The original Angular came into existence in 2009, and since then, there have been several revisions to account for the complexity of apps. Preparing for Angular interview questions and answers before your tech interview is necessary to get familiar with the type of questions you can expect.

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Here’s what we will cover in this guide to Angular interview questions and answers:

• Key concepts to focus on for an Angular interview
• Most commonly asked interview questions during Angular interviews
• Profile-specific interview questions on Angular framework
• How to prepare for Angular interview questions
• FAQs on Angular

Key Concepts to Focus on for an Angular Interview

Angular is an extensive framework. But don’t get overwhelmed by the wide range of topics you need to learn. Focus on these core concepts, and you’ll sail through:

• JavaScript
• Typescript
• Angular Framework
• RxJS
• HTML/CSS

Also, make sure to focus on the questions for each iteration.

Do you know the differences between var and let keywords in JavaScript? Read this article to learn more.

Most Commonly Asked Interview Questions During Angular Interviews

Here are some of the most commonly asked interview questions at Angular:

1. What are services in Angular, and why are they used?
2. What is AOT compilation in Angular?
3. Talk about the key differences between components and templates in Angular.
4. What is the use of Angular CLI?
5. Is it possible to use an HTML template in Angular?
6. What are the benefits of using unit tests in Angular, and how is it done?
7. What's the difference between automatic and manual bootstrapping?
8. What's the difference between one-way and two-way data binding in Angular?

Profile-Specific Interview Questions on Angular Framework

This section will help you know more about profile-specific Angular interview questions.

Angular Developer Interview Questions

Listed below are some of the developer interview questions asked at Angular:

1. Why was Angular introduced as a client-side framework?
2. What is the purpose of a filter in Angular?
3. What is the role of decorators in AngularJS?
4. Describe different types of filters in Angular?
5. How are DOM elements different from BOM?
6. Describe the advantages that Angular has over other frameworks.
7. What is a root component, and what role does the component play in Angular?
8. What is Angular Material, and why is it necessary for building web applications?
9. Does Angular 6 support the conversion of angular components into web components? What are some of the other new aspects of Angular 6?
10. Explain string interpolation in Angular. What is added within double curly braces?
11. Explain the difference between Angular Authentication and Authorization.

Angular 2 Interview Questions

Check out the list of Angular 2 interview questions mentioned below:

1. How will you declare a component in Angular 2?
2. What is lazy loading in Angular 2?
3. Explain how data binding has been improved in Angular 2?
4. Explain ECMAScript.
5. How will you cache observable data in Angular 2?
6. Explain structural directives in Angular 2.
7. How will you declare components in Angular 2?
8. What are the component-specific hooks in Angular 2?
9. List out the advantages Angular 2 has over Angular 1.
10. Describe the meaning of component lifecycle in Angular 2.

Read this article on Angular 2 interview questions for more sample questions.

Angular 4 Interview Questions

See the interview questions for Angular 4 mentioned below:

1. Explain what the digest cycle is in Angular?
2. What does lean component mean in Angular?
3. Explain the differences between scan() and reduce () in Angular?
4. How will you handle HTTP error responses in Angular 4?
5. What is the use of a subscribe method in Angular 4?
6. What are the different directives in Angular 4?
7. Define unit testing in Angular 4?
8. What is ElementRef in angular 4?
9. Why is deep linking important in Angular 4?
10. Explain the process of sending and setting cookies in Angular 4.

Note: Angular 4 was announced in 2016, skipping version 3 to avoid confusion due to the misalignment of the router package's version, which was already distributed as v3.3.0.

Angular 5 Interview Questions

1. Talk about the building blocks of Angular 5.
2. What is the use of viewEncapsulation?
3. What is routing in Angular 5?
4. What are the ways in which data binding can be done?
5. What is an AsyncPipe?
6. What is Redux?
7. Provide proper generation logic of Component, Pipe, Class, Directive, Service, and Module for Angular 5.
8. Explain the proper lifecycle hooks for the application development in Angular 5?
9. How do you differentiate  Constructors from OnInit?
10. Are there any differences between Activated Route and Router Route in Angular 5?

Angular 6 Interview Questions

1. Tell us about the various types of filters in Angular 6?
2. Explain what a safe navigation operator in Angular 6 is?
3. Why do we have @input and @output in Angular?
4. What is Route Guards in Angular 6?
5. What is template expression in Angular 6? Explain using syntax.
6. What is bazel and closure compiler in Angular 6?
7. Explain what is traceur compiler in Angular 6.
8. Explain the differences between angular service and factory.
9. What is a zone in Angular 6?
10. Explain the differences between constructor and ngOnInit in Angular 6?

For more Angular 6 interview questions, read our article on Angular 6 Interview Questions for a comprehensive list of sample questions.

Angular 7 and Angular 8 Interview Questions and Answers

Browse through the interview questions and answers to get a better sense of what to expect:

1. Explain subscribing and multicasting in Angular?

When someone subscribes, at the moment, the observable instance aids in the development of the values. In contrast, broadcasting the list of multiple subscribers in a single execution is known as multicasting. The only observable here is that there are no registered listeners on the document. Whatever happens, the values can be sent to each subscriber.  

2. What are the utility functions of RxJS?

The functions include:

• map() : Used to map values of different data types
• filter() : Used for filtering streams
• concat() : Used to concatenate multiple strings
• merge(): Used to recursively descend into object properties in the source copy while forming a deep copy of the same.

3. Explain the difference between Parameterized Pipes and Chaining Pipes.

In Angular, any number of parameters can be passed to the pipe using a colon (:), this method is known as Angular Parameterized Pipes. Whereas Chaining Pipes involves chaining multiple pipes together by associating more than one pipe and then transforming the final output with all the pipes applied.

4. What are the types of Forms supported by Angular 7?

There are two types of Forms available in Angular 7.

• Reactive Forms: It uses an explicit and immutable approach to managing the state of a form at a given point in time.
• Template-driven Forms: All logics, validations, controls are written in the template part.

5. What is NgUpgrade?

A library in Angular that allows us to upgrade Angularjs (1.X) application to Angular gradually. It lets you run Angular side-by-side along with AngularJS without breaking the application. NgUpgrade can be installed using the npm command npm install @angular/upgrade -- save.

6. List out the advantages of Bazel in Angular 8?

• You can use the same tool for both frontend and backend.
• There are incremental build and test options.
• You can carry out more customization and on Bazel.

7. What is the reason for using template-driven forms in Angular 8?

This is to support the addition of simple forms to applications where scalability is not an issue.

8. How will you check the type of value assigned to a given variable in Angular 8?

In Angular 8, the type of checks can be used for checking the kind of value assigned to a given variable.

9. Explain the use of NgUpgrade in Angular 8?

It is one of the upgrade libraries of Angular 8, mostly used to integrate both Angular and AngularJS components in an application. It helps bridge the gap between the Dependency Injection Systems in AngularJS and Angular.

10. What is Ivy in Angular 8?

It is the render engine of Angular 8. It makes applications simpler, smaller, and faster and also reduces the bundle size by at least 30%.

Check out our article on Angular 7 interview questions for more sample questions.

Angular Interview Questions for Beginners

Beginners can expect to be grilled about the basics of the Angular framework. Some of the sample questions include:

1. What is data binding? Which type of data binding does Angular deploy?
2. Differentiate between Angular and AngularJS
3. What are annotations in Angular?
4. What is the use of templates in Angular?
5. What is an AOT compilation, and what are its advantages?
6. Why are there Pipes in Angular?
7. What is an ngModule?
8. What is the meaning of scope in Angular?
9. What are Single Page Applications (SPA)?
10. What is Typescript?

Angular Security Interview Questions

1. How to prevent Cross-Site Scripting (XSS) in Angular?
2. How Angular Protects from XSS Attacks?
3. From a security standpoint, what are the key points to bear in mind when you are developing Angular apps?
4. What is Transpiling?
5. Describe the Angular Security best practices.
6. Why should we implement CSP?
7. How will you prevent Cross-site request forgery on Angular?
8. Why should you avoid modifying angular copy?
9. Do you recommend using DOM’s APIs directly?
10. What are reducers in Angular 4?

Angular Interview Questions for a Senior Developer

1. Describe what happens when a double click event takes place.
2. What is the difference between prefix $ and $$?
3. What is a SPA in AngularJS?
4. Explain scope object in AngularJS
5. How can you optimize Angular performance?
6. Talk about the differences between Constructor and ngOnInit?
7. How will you boot AngularJS?
8. Define “Page not found” route
9. Design a component with a button click to show and hide text by clicking.
10. Define JIT and AOT.

Angular Design Patterns Interview Questions

1. Why should someone use design patterns?
2. What is an observable pattern?
3. Define Proxy pattern.
4. Describe View Pattern.
5. What are the Web Design Patterns in Angular 8?
6. Is Angular an MVC design pattern?
7. Describe dependency injection DI.
8. What is the difference between a factory and abstract factory patterns?
9. What is a Prototype Pattern?
10. What is a Singleton Pattern?

Angular vs. React Interview Questions

1. What is Angular?
2. What is React?
3. When it comes to DOM, explain the differences between Angular and React.
4. What are the 5 main advantages of React?
5. What are the shortcomings of Angular?
6. Is Angular better than React?
7. Why do we consider React to be faster than Angular?

UI Developer Angular Interview Questions

1. Explain the basic steps to unit test an AngularJS filter?
2. How is data shared between controllers?
3. Explain the importance of a digest cycle.
4. What directive would you recommend to hide elements from the HTML DOM by removing them from that DOM not changing their styling?
5. What are ngIf and ngFor?
6. How is metadata represented in Angular?

Advanced Angular Interview Questions

1. How do you write unit test cases in Angular?
2. What is the difference between Scan and Reduce in RxJS?
3. What is the difference between flatmap and concatmap in Angular?
4. Name the security principles in Angular development.
5. How does Node.js overcome the problem of blocking of I/O operations?
6. What is Angular Ivy?
7. What is NGXS?
8. Describe AsyncPipe in Angular?
9. Describe the Core Dependencies of Angular 7?

Angular Architecture Interview Questions

1. Describe the building blocks of Angular applications.
2. Explain the need for factory function in AngularJS.
3. Create a pictorial representation of Angular architecture.
4. How is Dependency Hierarchy created?
5. What is HttpClient and its benefits?
6. What is the purpose of the base href tag?
7. What are Single Page Applications, and how do they function in Angular?
8. What function is called when an object is created in TypeScript?
9. How similar is AngularJS to Angular 2?
10. How to perform error handling?

Angular Framework Interview Questions

1. Why have client-side frameworks like Angular been introduced?
2. Which framework should you choose if you want to design mobile applications on AngularJS?
3. What is Angular Expression? Explain the key difference between angular expressions and JavaScript expressions.
4. What is a bootstrapping module?
5. What is the purpose of module.exports?
6. How is Node.js better than other frameworks most popularly used?
7. Explain injector in AngularJS.
8. Explain host view in Angular.
9. Explain property binding in Angular.
10. Explain the way of sharing data between components.

AngularJS and Node.js Interview Questions

1. List the advantages and disadvantages of AngularJS
2. Is AngularJS dependent on JQuery?
3. What do you mean by directives in AngularJS?
4. What role do controllers play in AngularJS?
5. What is a module in AngularJS?
6. What is the reason for Node.js to be single-threaded?
7. Describe event-loop in Node.js?
8. Explain the manner in which Node.js overcomes the problem of blocking of I/O operations?
9. What is the main reason behind separating express app and server?
10. Explain the exit codes of Node.js?

Angular Routing Interview Questions

1. Explain how the Angular router works.
2. How do Angular JS routes work?
3. Describe how you will initialize a select box with options on page load?
4. What is an Angular router?
5. Talk about the directive used for rendering a matched component in angular routing?
6. Demonstrate navigating between different routes in an Angular application.
7. Point out the differences between ActivatedRoute and RouterState, with reference to Angular.
8. What is an activated route?
9. What are router events?
10. What is the reason for using the Wildcard route?

RxJS Angular Interview Questions

1. Talk about the most outstanding features of RxJS
2. Explain the biggest advantages of Reactive Programming
3. What are the core principles of Redux?
4. Explain if there are any similarities between Redux and RxJS?
5. Explain the differences between BehaviorSubject and Observable in RxJS?
6. Define an Observable in RxJS
7. What are the advantages of RxJS Observables over RxJS Promises?
8. What does one mean by Asynchronous when the term is used in the context of RxJS or Reactive programming?
9. What is the role of a subject in RxJS?
10. What is RxJS Map? Explain the use of Higher-Order Observable Mapping.

Difficult Angular Interview Questions

If you are an advanced software developer, expect the questions to get a lot harder. Based on the feedback received from our alumni, here are some questions previously asked by interviewers:

1. What is ngOnInit? Can you define it?
2. What is Bootstrap, and how will you embed it in Angular?
3. Tell us the type of DOM that Angular implements?
4. Explain the difference between Reactive and Template forms?
5. What is the role of  Promises and Observables in Angular?
6. Explain the @Component Decorator.
7. Explain the common modules and ngmodules automatically added in angular apps? What errors will occur if these are not added?
8. How will you minify Angular applications?
9. What is :host property in CSS in Angular application?
10. Explain the benefits of statics class.

How to Prepare for Angular Interview Questions

Mentioned below are a few tips on how you can prepare for your Angular interview:

• Working on Angular requires proficiency in different languages. Hence, be thorough with various programming languages, including JavaScript, TypeScript, and HTML coding.
• Thoroughly research the company you are interviewing to understand the different applications that would need the angular framework.
• Schedule as many mock coding interviews as you can to brush up on your programming abilities.
• Since Angular has various iterations, you need to prepare thoroughly for each of them. As a software developer, you should be able to show the recruiters that you understand the fine differences between each iteration and are up-to-date with the latest developments. Remember that even though the old iterations will not be developed any further, they still receive support. That’s why the interviewer will be keen to know how thorough you are with various versions that Angular supports.
• If you are applying for front-end developer roles, you also need to be familiar with basic data structure concepts.

Want more tips on how to crack tough tech interviews? Read this article on understanding tech interviews at FAANG and how to crack them.

FAQs on Angular

1. What are the skills an Angular developer needs?

An Angular developer should have an understanding of Core JavaScript, in-depth knowledge of the Angular framework, good command of TypeScript, knowledge of web markup, primarily focusing on HTML language and CSS, knowledge of Node and Webpack, and experience with RESTful API integration.

2. Is there a way to get certified in Angular?

There are no official courses, but you can always enroll in an online course to receive a certification.

3. What are some of the popular websites that use the Angular framework?

Google, Forbes, PayPal, Nasdaq -- all these websites are based on the Angular framework.

4. What’s the best way to learn Angular from scratch?

You can start with angular.io, which is the official documentation. It contains the different sections for the different concepts in a sequential manner.

5. Why do frontend developers need to master HTML and CSS?

HTML and CSS are the most fundamental scripting languages used for front-end development. While HTML gives the website, web page, or application the overall structure, CSS helps with the visuals, text, fonts, layouts, and templates. Therefore, being an expert in both HTML and CSS is crucial to becoming a successful front-end developer.

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