This comprehensive guide covers 50 essential Angular interview questions that every Angular developer should know. These questions cover fundamental concepts, components, services, routing, directives, dependency injection, and Angular best practices commonly asked in technical interviews.

## Core Angular Concepts

Understanding Angular's core concepts is essential. These questions test your knowledge of components, modules, services, and the Angular architecture.

## Components & Templates

Components are building blocks of Angular applications. Master these questions to demonstrate your understanding of component lifecycle, data binding, and template syntax.

## Services & Dependency Injection

Services provide shared functionality across components. These questions cover dependency injection, services, singletons, and how Angular manages dependencies.

## Routing & Navigation

Angular Router enables navigation between views. These questions cover routing configuration, guards, lazy loading, and navigation patterns.

## Directives & Pipes

Directives modify DOM, pipes transform data. These questions cover built-in and custom directives, pipes, and when to use each.

## Advanced Angular

Advanced topics include change detection, RxJS, forms, HTTP, and performance optimization. These questions test your deep understanding of Angular.

Comprehensive collection of 50 essential Angular interview questions covering components, services, routing, directives, and Angular best practices.

Angular Interview Questions: 50 Essential Questions for Developers

Angular 21 brings exciting new features and improvements. If you're building Angular apps in 2025, you need to know what's new. Let's explore the latest features and how they make development easier and faster.

## What's New in Angular 21?

Angular 21 introduces improved performance, new APIs, better developer experience, and modern features. The framework continues to evolve, making it easier to build scalable applications.

## Performance Improvements

Angular 21 includes optimizations for faster rendering, smaller bundle sizes, and improved change detection. These improvements happen automatically, but understanding them helps you write better code.

## New APIs and Features

Learn about new directives, improved dependency injection, and modern patterns. Angular 21 makes common tasks easier and provides better tools for building complex applications.

## Migration and Compatibility

I'll show you what's changed and how to migrate from older versions. Most changes are backward compatible, but knowing what's new helps you take advantage of improvements.

## Getting Started

I'll walk you through setting up Angular 21 and using the new features. This is how you build modern Angular applications in 2025.

Discover Angular 21's latest features and improvements. Learn about new APIs, performance enhancements, and modern Angular development patterns. Stay up-to-date with the latest Angular release.

Angular 21: What's New and Latest Features

Components are the heart of Angular applications. Everything you build is a component. Understanding components deeply is essential for building great Angular apps.

## What are Components?

Components combine template (HTML), styles (CSS), and class (TypeScript) to create reusable UI pieces. Each component has its own scope and can communicate with other components through inputs and outputs.

## Component Lifecycle

Angular components go through lifecycle hooks - ngOnInit, ngOnChanges, ngAfterViewInit, and more. Understanding these hooks lets you perform actions at the right time, like fetching data or cleaning up.

## Data Binding

Angular provides powerful data binding - property binding, event binding, two-way binding with ngModel. This connects your component class to the template, making dynamic UIs easy.

## Component Communication

Components communicate through @Input and @Output, services, or parent-child relationships. Understanding these patterns is crucial for building maintainable applications.

## Best Practices

I'll show you how to structure components, when to create new components, and how to make them reusable. These patterns will make your code cleaner and more maintainable.

Master Angular components - the building blocks of Angular applications. Learn component lifecycle, data binding, event handling, and component communication. Essential for Angular development.

Angular Components: Building Reusable UI

Services are where you put business logic, data access, and shared functionality. Angular's dependency injection makes using services easy and testable. Understanding this is crucial for Angular development.

## What are Services?

Services are TypeScript classes that provide functionality across your application. They're perfect for API calls, data sharing, logging, and any logic that multiple components need.

## Dependency Injection

Angular's DI system automatically provides services to components that need them. You don't create services manually - Angular does it for you. This makes code testable and maintainable.

## Creating Services

Use @Injectable decorator to mark a class as a service. Register it in providers array or use providedIn: 'root' for app-wide singleton. I'll show you both approaches.

## Sharing Data

Services are perfect for sharing data between components that aren't parent-child. Store data in services and inject them where needed. This is cleaner than prop drilling.

## Best Practices

I'll show you how to structure services, when to use them, and how to make them testable. These patterns will make your code professional and maintainable.

Master Angular services and dependency injection. Learn how to create services, inject them, and share data across components. Essential for building maintainable Angular applications.

Angular Services and Dependency Injection

Angular Router enables navigation between views in your application. Understanding routing is essential for building single-page applications. Let's learn how to set it up and use it effectively.

## Setting Up Routing

Configure routes in your app using RouterModule. Define paths, components, and navigation rules. Angular Router handles URL changes and displays the right component.

## Route Parameters

Pass data through routes using route parameters, query parameters, or route data. Access them in components to load specific data or configure views.

## Nested Routes

Build complex navigation with nested routes. Child routes inherit parent route configuration, allowing you to create hierarchical navigation structures.

## Route Guards

Guards control navigation - canActivate to check permissions, canDeactivate to prevent leaving unsaved changes, resolve to preload data. They're essential for secure and user-friendly apps.

## Lazy Loading

Load modules on-demand with lazy loading. This reduces initial bundle size and improves app performance. Essential for large applications.

## Navigation Programmatically

Navigate from code using Router service. Perfect for redirects, form submissions, and conditional navigation.

Master Angular routing - navigation, route parameters, nested routes, and route guards. Learn how to build single-page applications with proper navigation. Essential for Angular development.

Angular Routing: Navigation and Route Guards

Forms are how users interact with your application. Angular provides two approaches - template-driven and reactive forms. Understanding both helps you choose the right approach for your needs.

## Template-Driven Forms

Template-driven forms use directives in templates (ngModel, ngForm). They're simpler for basic forms but less flexible. Angular handles form state automatically.

## Reactive Forms

Reactive forms use FormBuilder and FormControls defined in the component class. They're more powerful, testable, and flexible. Recommended for complex forms.

## Form Validation

Angular provides built-in validators (required, email, min, max) and supports custom validators. Show validation messages and disable submission until valid.

## Handling Form Data

Access form values, handle submission, reset forms, and manage form state. I'll show you how to work with form data effectively.

## Dynamic Forms

Build forms dynamically based on data or user input. Reactive forms make this easier with FormArray and dynamic controls.

## Best Practices

I'll show you when to use each approach, how to structure forms, and validation patterns. These skills are essential for building production-ready forms.

Master Angular forms - template-driven and reactive forms. Learn form validation, handling user input, and building complex forms. Essential for collecting and validating user data.

Angular Forms: Template-Driven and Reactive Forms

Build modern web applications with Angular framework, components, and services.

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