Angular Interview Questions and Answers 2025

Introduction to Angular

Angular is a popular open-source web application framework developed and maintained by Google. It allows developers to build dynamic and responsive web applications using a component-based architecture.

Angular is a TypeScript-based framework for web application development. The new Angular or Angular 2+ (Angular CLI) is an improved version of the older AngularJS. Like its predecessor, Angular is also open-source and has been created by Google’s Angular team.

The upgraded Angular is a full rebuild of AngularJS and provides a holistic system for reusing code and building web applications in a modular fashion. Due to Angular’s adaptive features, many developers prefer using this development framework for deploying native applications (mobile or desktop) and web applications.

Angular was introduced to fulfil the demand for creating dynamic single-page web environments. To create progressive web applications that can also be deployed as native applications, Google needed to simplify the testing and development of the application architecture. This is the core reason why the old AngularJS, as well as the updated Angular, were developed

In this article, we will provide an introduction to Angular and cover some common angular interview questions and answers. You can opt for our Full Stack Development course to kickstart your career.

1. What is the difference between Angular and AngularJS?

Angular is based on TypeScript, while AngularJS is based on JavaScript. Angular also has more improved features such as dependency injection and command-line tools. The newer Angular is more adaptive and optimized for newer mobile browsers.

2. How can projects be built with Angular?

The Angular architecture comprises NgModules, components, services, routing, and dependency injection. Using these building blocks, you can start building projects in Angular.

3. What is meant by the host view in Angular?

Host views can be defined as single views that components are associated with.

4. What is meant by pipes in Angular?

Pipes provide the ability to transform input data into the output of your choice. One can create custom pipes to modify the target data.

5. What is the difference between TypeScript and JavaScript?

TypeScript is an objective-oriented programming language while JavaScript is a scripting language. For client-side operations, TypeScript is the more powerful alternative as compared to JavaScript. TypeScript is backward compatible with JavaScript and supports JavaScript libraries. Also, TypeScript is capable of supporting .js files (by replacing .js with .ts).

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6. What are the directives that can be used in Angular?

Three directives can be used in Angular. These three are components, structure directives, and attribute directives. Components are template directives while structure directives are used for manipulating elements in DOM structures. The attribute directives are used for modifying the behaviour or attributes of a DOM element.

7. How is data shared between components in Angular?

You can share data between components in different ways based on if it is parent to child, child to parent, or between unrelated components. If data needs to be shared from parent to child, you need to use the @Input decorator. Similarly, when sharing data from child to parent, you can use the @Output decorator. If you wish to share data between unrelated components, you need to write a single service and inject it into both the target components.

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8. What is referred to as Data binding in Angular?

Data binding can be defined as a way of sharing data between components and the views that the components are associated with.

9. What are Angular services?

Services in Angular exist to provide modular functions. Components can be injected with services to carry out various functions such as fetching data from the server. Code that is created into a service can be reused for any component.

10. What is meant by dependency injection in Angular?

Dependency injection can be described as a design pattern that helps to make Angular projects more modular. Dependencies require objects or classes to depend on other classes for carrying out their operation.

11. Useful Features of Angular

Here are some of the extremely useful features Angular offers:

• Build dynamic web environments that simulate an application-like experience.
• Have the capability to create high-performance native applications that can work offline as well (once loaded).
• Create applications for mobile and desktop that can access native APIs for the Operating Systems.
• Transform templates into code that can work in JavaScript VMs (Virtual Machines).
• Development with Angular is fast,and you can reuse existing code.
• Only load code that is required for rendering the view you need.
• Angular offers automated code-splitting with the help of the component router.
• Create immersive and powerful user interfaces with available template syntax.
• Use command-line tools to build, modify, test, and deploy.
• Get Angular feedback in most of the popular Integrated Development Environments and editors.
• Use unit testing capabilities with Karma.
• Design animations and high-performance graphics with Angular’s API that does not require you to use complex code.

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12. The Architecture of Angular

The Architecture of Angular mainly consists of 7 parts. Let’s check what they are in brief:

• Modules: Modules in Angular declare compilation contexts for a group of components. All Angular applications have root modules that provide bootstrap mechanisms for launching the application. There are a lot of functional modules in a generic web application.
• Components: Angular applications have a root component that helps in connecting the DOM of a page with component hierarchies. There must be at least 1 component in an Angular application. Components define classes that contain the logic and data of the applications. These components form associations with HTML templates that help in defining the views that will be rendered in the target environments.
• Templates: Templates help in combining Angular markups with HTML to manipulate or alter the HTML elements before they are rendered. Template directives also define the logic of the program.
• Binding: Binding markups connect application data with the page document object model or DOM.
• Services: Services are used for sharing logic or data that is not yet associated with the target views. You can create services to inject dependencies into classes.
• Dependency Injection: Dependency injection helps in keeping components efficient and clean. For example, dependencies help in reusing code and delegating functions. Dependencies can make other services carry out operations such as data fetching or user-input validation.
• Routing: Routers help in defining navigation paths between various application views and states inside your application. The routing module helps in navigating among the hierarchies in the program.

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13. Advantages of Using Angular

One of the main advantages of using Angular is that it uses TypeScript. TypeScript is more powerful than JavaScript and allows JavaScript code to be converted into TypeScript. This programming language is more optimized and runs on all kinds of devices, operating systems, and browsers.

By using TypeScript for Angular, developers can also use JS libraries and existing JavaScript code. The powerful language also supports static typing and has an interface, unlike JavaScript. Like this, the upgraded Angular provides many advantages to developers over the older Angular JS or any other JavaScript-based frameworks.

Here are the advantages of using Angular:

• Server-side rendering.
• Scalability and support for projects with huge data requirements.
• A fast and powerful framework for deployment.
• A universal framework that allows real-time rendering in HTML and CSS.
• Support for SEO-optimized web pages.
• Efficient code loading and also the ability to reuse code or modules.
• Great templates and dynamic UI.
• Easy and modular testing.
• Command-line tools for easier builds.
• Needs less code for great dynamic environments.
• Accessible with guides, sample projects, testing infrastructure, and ARIA-enabled components.
• Support for mobile browsers.
• Dependency injection.

More than anything, developers love using Angular due to the decreased build times and deployment times. Angular is also extremely adaptive and provides ample scope for scaling projects. Also, this web framework makes your web applications extremely optimized for being rendered in various browsers and environments.

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14. What are the major differences between Angular and Angular js?

• The Angular allows developers to fill the necessary gap between frontend development and client-side architectures. Angular, like AngularJS, makes it very easy to work on full-stack development. AngularJS offered MVC (Model-View-Controller) and MVVM (Model-View View-Model) features which have been replaced by components and directives in Angular.

• Angular JS was incredibly popular in the last decade; however, it is not optimized for modern mobile browsers. Angular, on the other hand, works great for all popular mobile browsers. Angular also supports dependency injection and is easier to manage as compared to Angular JS. The new Angular is also very effective in developing and maintaining large applications, whereas Angular JS is simply optimized for small applications.

• Angular has a better architecture than Angular JS as well. With the growing popularity of the newer 2+, Google’s Angular team slowly drew back the support for the older web framework and started completely focusing on Angular CLI. Another important difference between the older and newer Angular is that Angular JS was based on JavaScript while Angular 2+ is based on Microsoft’s TypeScript.

• Like its predecessor, Angular is represented by the ‘A’ in the ‘MEAN’ stack. MEAN stack stands for MongoDB, Express, Angular, and Node. MongoDB is used for the database, while Express.js is used for the server framework. Node.js is the server runtime environment (client-side), while Angular is used for developing the frontend.

• Angular helps develop the frontend by manipulating the data more effectively. Especially in comparison to older frontend technologies and even AngularJS, Angular 2+ is extremely efficient. Being both faster and smoother due to core functionalities shifting to more compatible modules, the time required for deployment and development can also be minimized.

15. What are Angular NgModules and how are they used to organize an Angular application?

Angular NgModules are a core concept in allowing developers to group related components, directives, and services into cohesive blocks of functionality. This helps with code organization and maintainability. Understanding NgModules is important for angular interview questions and answers related to Angular architecture and development.

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16. Explain the difference between Promises and Observables in Angular?

Understanding the difference between Promises and Observables is important to prepare for Angular interview questions and answers related to asynchronous programming in Angular.

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17. What are Angular Forms and how are they implemented in an Angular application?

Angular Forms are a powerful feature in Angular for building complex and dynamic forms. They are implemented using reactive forms or template-driven forms. Understanding Angular Forms is important for angular interview questions and answers related to form development in Angular applications. You can also explore Full-Stack Developer Salaries in India.

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18. Differentiate between Angular and AngularJS.

This is one of the popular angular interview questions.

19. What is the difference between an Annotation and a Decorator in Angular?

This is another of the common angular interview questions.

20. What do you understand by controllers in Angular?

In Angular, controllers are replaced by components. Components are responsible for managing the data and behavior of the view. Understanding this change is important for angular interview questions and answers related to Angular architecture and development.

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21. What is the purpose of a filter in Angular?

In AngularJS, filters were used to format data in views. In Angular, pipes have replaced filters for similar purposes. Understanding the difference will help in angular interview questions and answers related to Angular development.

22. What is AOT compilation in Angular?

AOT (Ahead-of-Time) compilation is a process of compiling Angular code during the build phase, and is one of the most asked angular interview questions.

23. What are the essential components of Angular?

These are some of the major components of Angular:

• Modules
• Templates
• Directives
• Services, Dependency Injection
• Routing
• HTTP Client
• Pipes

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24. What is the difference between Observables and Promises in Angular?

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25. What are decorators in Angular?

Decorators are a type of design pattern in Angular that modify the behavior of classes, methods, and properties by wrapping them with additional functionality, using metadata and functions. Along with angular interview questions and answers, get to know what is full-stack development?

26. What is a provider in Angular?

A provider in Angular is a recipe for creating a service that can be injected into components. This is one of the common angular interview questions. It is an object that instructs the dependency injection system on how to create a service and how to provide it to components that request it.

These angular interview questions and answers are designed to help you gain an edge, and secure the right knowledge required.

27. How does Angular fit into Full-Stack Development?

When using Angular for full-stack development, you can build both the frontend and the client side of the application with a single language. Now, one can use a variety of database technologies. However, MongoDB is used for the MEAN stack as it is known to be extremely scalable as well as powerful.

When building a full-stack web application, Angular can help in designing and building both mobile and desktop versions of the program. These applications are mostly known as Single-Page Applications and are more dynamic than generic web pages. Angular works well with Node and Express (MEAN stack).

Angular is especially useful for creating fully functional data-driven websites such as a CRUD (Create, Read, Update, Delete) application. With the help of Node.js as the foundation for the stack, Angular can seamlessly stitch together web applications that can be rendered in the most optimized manner. Node helps you deploy web servers that allow you to build the web application.

Express.js takes care of repetitive tasks in the stack. With the help of Express, you can easily use Angular to deploy your applications as fast as possible. Angular pieces together the entire full-stack development process while the other technologies lay the foundation and provide the resources to support the application.

So, what is a full-stack developer? Full-stack developers can be defined as individuals who can handle the frontend, the backend, and the database of the web application all on their own. Is web development a good career? Yes, it is, especially with technologies such as Angular making it easy for developers all across the globe.

And, it is not just the development-deployment process that is becoming easy. We are also able to build more dynamic, interactive, and advanced single-page applications with the technology stacks we have at our disposal.

Angular is fast, powerful, and adaptive. Using Angular 2+, developers can complete projects faster while making their applications optimized for modern mobile browsers. Due to the use of TypeScript, developers also do not need to rely on other backend languages (client-side) such as Python.

The team behind the framework recommends switching to Angular 2+ and has stopped Angular JS’s updates for compatibility, jQuery issues, and security patches. As of January 2022, the new Angular is the only recommended frontend web framework by Google. If you are wondering how to become a full-stack developer, it is highly recommended that you look into the MEAN stack and try learning Angular.

Angular is a great skill to have for web development. If you wish to acquire the skills required for full-stack developer roles, a great place to start is Hero Vired’s Certificate Program in Full Stack Development. The program covers key fundamentals of full-stack development, along with how to deploy applications using the cloud. The program is powered by Codeacademy and includes exclusive learning content.