Angular Interview Questions

Question	Answer
What is Angular and how is it different from other JavaScript frameworks?	Angular is a TypeScript-based open-source front-end web application platform. It is different from other JavaScript frameworks in that it uses a hierarchical dependency injection system, provides a powerful templating system, and has a modular architecture that allows for easier code management and scalability.
What are the main components How do they work together?	`components` - Components represent different parts of the user interface, services handle data and functionality that can be shared across components. `services` `directives` - Allow to attach behavior to elements in the DOM `templates` - Define the structure of the user interface `*ngTemplateOutput` `dependency injection` - Used to manage dependencies between different components and services.
`Data binding` in Angular and how does it work?	Allows you to synchronize data between the model and view components. There are four types of data binding in Angular `Two-way` - `*ngmodel` `Interpolation` `Property binding` `Event binding`
`Observables`	`Observables` are a core feature of the `RxJS` library, which is used extensively in Angular. - Used to handle `asynchronous` operations, such as HTTP requests and user input events. - Provide a way to handle asynchronous data streams in a consistent and predictable way.
What are Angular directives and what is their purpose?	Angular directives are instructions in the DOM that tell Angular how to transform the DOM. They are used to attach behavior to elements in the DOM, manipulate the DOM, and provide logic for other components and directives.
What is the Angular CLI and how do you use it?	The Angular CLI is a command-line interface tool that helps developers create, manage, and build Angular applications. It provides a number of commands that can be used to create new components, services, and modules, run tests, and build the application for production. To use the Angular CLI, you need to install it globally using npm, and then run commands in your terminal or command prompt.
How do you create and use services in an Angular application?	To create a service in an Angular application, you can use the `@Injectable()` decorator and the providedIn property to specify where the service should be provided. To use a service, you can inject it into a component or another service using dependency injection.
What are Angular pipes and how do you use them?	Angular pipes are a way to transform data in an Angular application. They allow you to format and display data in a way that is appropriate for the user. Pipes can be used in templates to modify data before it is displayed. There are built-in pipes in Angular, and you can also create your own custom pipes.
How do you handle errors and exceptions in an Angular application?	Angular provides several mechanisms for handling errors and exceptions in an application. You can use try/catch blocks, error handlers, and observables to handle errors and exceptions. You can also use third-party libraries and tools to simplify error handling in your application.
What is lazy loading in Angular and how does it improve application performance?	Lazy loading is a technique in Angular that allows you to load parts of your application on demand, rather than all at once. This can improve application performance by reducing the amount of initial code that needs to be loaded, and by allowing the user to interact with the application more quickly. Lazy loading can be implemented using the loadChildren property in the routing module.
How do you test an Angular application using different testing frameworks?	Angular provides built-in support for testing applications using the `Jasmine` testing framework. You can also use other testing frameworks such as Karma `or` Protractor`. To test an Angular application, you can write unit tests for individual components or services, integration tests to test the interaction between different components, and end-to-end tests to test the entire application. Testing can be automated using tools such as Karma and Protractor.
Authorization in Routing	Route Guards