Top 10 Angular Interview Questions and Answers

 Angular is a powerful framework for building web applications. To help you prepare for your next interview, here are ten common Angular interview questions along with detailed answers.

1. What is Angular?

Answer: Angular is a platform and framework for building single-page client applications using HTML and TypeScript. Developed by Google, it provides a robust set of tools and features for developing dynamic web applications, including a component-based architecture, dependency injection, and powerful routing capabilities.

2. What are components in Angular?

Answer: Components are the fundamental building blocks of an Angular application. Each component encapsulates its own template, styles, and behavior. Components are defined using the @Component decorator and consist of a TypeScript class, an HTML template, and optional CSS styles. They enable modular development and enhance code reusability.

3. What is a module in Angular?

Answer: An Angular module is a class annotated with the @NgModule decorator that organizes an application into cohesive blocks of functionality. Each module can contain components, services, directives, and pipes. The root module, typically named AppModule, bootstraps the application and can import other modules to enhance functionality.

4. What is dependency injection in Angular?

Answer: Dependency injection (DI) is a design pattern used in Angular to achieve Inversion of Control (IoC) between classes and their dependencies. It allows services to be injected into components and other services, promoting modularity and reusability. Angular’s injector creates and manages instances of services, making them available to the components that need them.

5. What are services in Angular?

Answer: Services in Angular are singleton objects that encapsulate business logic or data-fetching operations. They are typically used to share data and functionality across components. Services are created using the @Injectable decorator, which allows Angular to inject them into components and other services.

6. What is routing in Angular?

Answer: Routing in Angular allows navigation between different views or components in a single-page application. The Angular Router is a module that enables developers to define routes, manage navigation, and load components dynamically based on the URL. It supports features like route parameters, guards, and lazy loading.

7. What are pipes in Angular?

Answer: Pipes are a way to transform data for display in Angular templates. They take input data and return a transformed output, making it easier to format data (e.g., dates, currencies). Angular comes with built-in pipes like DatePipe and CurrencyPipe, and developers can also create custom pipes as needed.

8. What is Angular CLI?

Answer: Angular CLI (Command Line Interface) is a powerful tool that streamlines the development process by providing commands to create, build, test, and deploy Angular applications. It helps developers set up a new Angular project with a predefined structure, automate tasks, and manage dependencies efficiently.

9. What are lifecycle hooks in Angular?

Answer: Lifecycle hooks are methods that allow developers to tap into key events in a component’s lifecycle. Angular provides several lifecycle hooks such as ngOnInit, ngOnChanges, ngOnDestroy, and more. These hooks enable developers to perform actions at specific points, such as initializing data, responding to changes, or cleaning up resources.

10. What is two-way data binding in Angular?

Answer: Two-way data binding is a mechanism that allows synchronization between the model and the view in Angular. It means that any changes made in the UI are automatically reflected in the component's state, and vice versa. This is typically achieved using the [(ngModel)] directive, which combines property binding and event binding.