Angular is a popular open-source web application framework developed and maintained by Google. It is used for building dynamic single-page applications (SPAs) and is based on TypeScript, a superset of JavaScript. Angular provides a comprehensive set of tools, libraries, and features that allow developers to create robust and scalable web applications.

What is Angular and what are its key features?

• Angular is a popular open-source JavaScript framework for building web applications.
• Key features of Angular include two-way data binding, dependency injection, component-based architecture, routing and navigation, form handling and validation, and testing support.

What are Angular directives?

• Directives are markers on a DOM element that tell Angular to attach a particular behavior or functionality to that element or its children. There are three types of directives in Angular: component directives, structural directives, and attribute directives.

What are Angular modules and their importance?

• Angular modules are containers for organizing and packaging related components, directives, services, and other application artifacts. They help to modularize the application and provide better separation of concerns, reusability, and lazy loading capabilities.

What is a service in Angular and how do you create one?

• A service is a class in Angular that contains business logic, data manipulation, or shared functionality that can be used across multiple components. To create a service, you generate it using Angular CLI or manually create a class and register it in the Angular

What is Angular template reference variable and how is it used?

• A template reference variable is a reference to an element or directive within an Angular template. It is denoted by the # symbol and can be used to access the element or directive’s properties and methods from within the template or component code

What are Angular pipes and how are they used?

• Pipes in Angular are used for transforming and formatting data in templates. They allow you to apply transformations to data before displaying it. Angular provides built-in pipes like DatePipe, UpperCasePipe, LowerCasePipe, and you can also create custom pipes.

How can you communicate between sibling components?

• To communicate between sibling components, you can use a shared service. The service acts as a mediator between the sibling components and facilitates data sharing or event propagation.

What is Angular form validation and how is it implemented?

• Angular provides both template-driven and reactive forms for handling user input and performing form validation. Form validation involves validating user input, displaying error messages, and preventing form submission until the input is valid.

How do you handle HTTP requests in Angular?

• In Angular, you can handle HTTP requests using the built-in HttpClient module. You can make GET, POST, PUT, DELETE requests, handle headers, query parameters, and process the response using observables and operators provided by RxJS.

What are Angular guards and when are they used?

• Angular guards are used to protect routes in an application. They allow you to control access to routes based on certain conditions. There are different types of guards such as CanActivate, CanDeactivate, CanLoad, and Resolve that can be used in various scenarios.

How can you optimize the performance of an Angular application?

• To optimize the performance of an Angular application, you can implement strategies like lazy loading, code splitting, AOT (Ahead-of-Time) compilation, tree shaking, and minification. Additionally, optimizing change detection, reducing HTTP requests, and using caching techniques can also improve performance.

What is the purpose of Angular TestBed?

• Angular TestBed is a utility provided by Angular for testing components, services, and other Angular artifacts. It creates an isolated testing environment and provides methods and utilities to configure and interact with the tested components and services.

What is the difference between ViewChild and ContentChild in Angular?

• @ViewChild is used to query and access a single child component or element from the parent component, while @ContentChild is used to query and access a single projected content (transcluded) child component or element.

What is Angular animation and how do you implement it?

• Angular animation allows you to add animations to your application’s components and elements. It provides a powerful API for defining animations using triggers, states, transitions, and keyframes. Animations can be implemented using the @angular/animations module.

How do you handle authentication and authorization in an Angular application?

• Authentication and authorization in Angular can be handled using techniques like JWT (JSON Web Tokens), OAuth, or traditional session-based authentication. Angular interceptors can be used to add authentication headers to HTTP requests, and guards can protect routes based on user roles or permissions.

How can you handle form validation asynchronously in Angular?

• Angular provides the AsyncValidator interface, which allows you to perform asynchronous validation operations, such as validating against a server API. You can create a custom async validator function and attach it to a form control using the AsyncValidatorFn type.

How can you optimize the performance of Angular applications for mobile devices?

• To optimize Angular applications for mobile devices, you can use techniques like responsive design, lazy loading, and code minification. Additionally, you can use Angular’s built-in features like AOT compilation and tree shaking to reduce bundle size and improve loading times.

What is Angular Ivy and what benefits does it offer?

• Angular Ivy is the new rendering engine introduced in Angular version 9. It provides improved bundle size, faster compilation, better performance, and enhanced debugging capabilities. It also allows for more efficient tree shaking and enables better ahead-of-time (AOT) compilation.