Top 10 Senior Angular Developer Interview Questions & Answers in 2024

1. How does Angular handle dependency injection, and what are the benefits of using hierarchical injectors?

Angular uses hierarchical injectors for managing dependency injection. Each component has its injector, which is a child of its parent component's injector. This hierarchy allows components to inherit services from their ancestors. Benefits include encapsulation, lazy loading support, and the ability to override or provide services at different levels of the application.

2. Explain the concept of Angular Universal and how it addresses the challenges of server-side rendering (SSR) in Angular applications.

Angular Universal is a technology for server-side rendering in Angular applications. It allows rendering Angular applications on the server to enhance performance and facilitate search engine optimization (SEO). Angular Universal addresses challenges such as initial page load times and SEO by pre-rendering Angular applications on the server before sending them to the client.

3. Discuss the role of Angular Schematics in application development and provide examples of scenarios where custom schematics might be beneficial.

Angular Schematics automate the generation of boilerplate code and enhance developer productivity. Custom schematics can be beneficial in scenarios such as:

• Project Configuration: Automating the setup of project configurations.
• Component Generation: Creating custom schematics for generating components with predefined features.
• Code Standardization: Enforcing and standardizing coding conventions across the project.

Custom schematics streamline repetitive tasks and promote consistency in codebases.

4. How can you optimize the performance of an Angular application, and what tools can assist in identifying performance bottlenecks?

Performance optimization in Angular involves techniques like Ahead-of-Time (AOT) compilation, lazy loading, and using tools like Angular CLI, Chrome Developer Tools, and Augury for profiling and identifying bottlenecks. Analyzing the change detection cycle, optimizing template rendering, and minimizing network requests contribute to improved Angular application performance.

5. Explain Angular Reactive Forms and Template-Driven Forms, comparing their use cases and advantages.

Angular Reactive Forms and Template-Driven Forms are two approaches for handling forms in Angular applications. Reactive Forms are more explicit, model-driven, and suitable for complex forms with dynamic behavior. Template-Driven Forms rely on directives within templates and are simpler for basic forms. The choice between them depends on the form's complexity and the desired level of control.

6. How can you handle authentication and authorization in an Angular application, and what role do guards play in securing routes?

Authentication and authorization in Angular involve implementing mechanisms like JWT (JSON Web Tokens), OAuth, or custom authentication services. Route guards, such as CanActivate and CanActivateChild, play a vital role in securing routes. They allow developers to control access to specific routes based on the user's authentication status or other criteria.

7. Discuss the concept of Angular Content Projection and when you might use ng-content to create reusable components.

Angular Content Projection allows the insertion of content into a component from its parent component. The ng-content directive is used to define insertion points within a component's template. This feature is beneficial when creating reusable components with dynamic or variable content, allowing users of the component to inject their content into specific slots.

8. How can you implement lazy loading in Angular, and what are the benefits of using lazy-loaded modules?

Lazy loading in Angular involves loading modules on demand, reducing the initial bundle size and improving application loading times. To implement lazy loading, configure routes using the loadChildren property. Benefits include faster initial page loads, optimized resource utilization, and better user experience, especially in large-scale applications.

9. Explain Angular Pipes and provide examples of built-in pipes. Discuss scenarios where custom pipes might be necessary.

Angular Pipes transform and format data in templates. Built-in pipes include DatePipe, UpperCasePipe, and CurrencyPipe. Custom pipes might be necessary for scenarios like formatting or filtering data based on specific application requirements. They allow developers to encapsulate and reuse transformation logic for various data types.

10. Discuss the role of Angular Services and how they contribute to the modularity and scalability of an application. Provide examples of scenarios where services are essential.

Angular Services are singleton objects used for sharing logic and data between components. They contribute to modularity and scalability by promoting code reuse, maintaining a single instance of shared logic, and ensuring separation of concerns. Services are essential in scenarios such as:

• Data Sharing: Sharing data between components without direct coupling.
• Business Logic: Centralizing business logic to ensure consistency.
• HTTP Requests: Handling HTTP requests and providing a centralized point for API interactions.

Services enhance code maintainability, testability, and scalability in Angular applications.