Angular is one of the most popular front-end frameworks developed by Google. It is widely used for building dynamic web applications due to its robustness and efficiency. If you are preparing for an Angular-related role, it is crucial to be well-versed with commonly asked interview questions.
In this blog, we will cover Angular JavaScript interview questions ranging from beginner to expert level, ensuring that you are fully prepared for your next job interview.
Answer: Angular is an open-source TypeScript-based front-end framework developed by Google. It is used to build single-page applications (SPAs) and dynamic web applications with a structured MVC (Model-View-Controller) architecture.
Answer:
Component-based architecture
Two-way data binding
Dependency Injection (DI)
Directives and Pipes
Modular development structure
Powerful template system
Routing and navigation support
Answer:
FeatureAngularJS (1.x)Angular (2+)LanguageJavaScriptTypeScriptArchitectureMVCComponent-basedMobile SupportNoYesPerformanceSlowerFaster
Answer: Components are the building blocks of an Angular application. They control a portion of the UI and include:
Template (HTML) for defining the UI.
Class (TypeScript) for logic and data handling.
Styles (CSS/SCSS) for UI appearance.
Answer: Data Binding in Angular enables seamless synchronization between the UI and the model. It is of four types:
Interpolation: {{ expression }}
Property Binding: [property]="value"
Event Binding: (event)="method()"
Two-way Binding: [(ngModel)]="data"
Answer: Directives are instructions to manipulate the DOM. Types of directives include:
Structural Directives (*ngIf, *ngFor)
Attribute Directives (ngClass, ngStyle)
Custom Directives (User-defined)
Answer: Dependency Injection (DI) is a design pattern used in Angular to inject services and dependencies into components, making the application modular and testable.
Answer: Angular services are reusable classes that handle business logic, data management, and API interactions. They are provided using @Injectable() and injected via DI.
Answer: Angular’s Router module enables navigation between different views. Key concepts include:
RouterModule: Enables routing.
Routes: Defines paths and components.
RouterLink: Navigates between components.
Router Guards: Controls access to routes.
Answer: Lazy Loading is a technique where feature modules are loaded on demand instead of at the application’s startup, improving performance and reducing initial load time.
Answer: Observables are provided by RxJS and are used for handling asynchronous data streams. They are used in Angular for HTTP requests, event handling, and reactive programming.
Answer: Angular uses a Change Detection Mechanism to update the DOM whenever data changes. It operates in two modes:
Default Change Detection: Detects changes automatically.
OnPush Strategy: Detects changes only when input properties change.
Answer: Pipes are used to transform data in templates. Examples include:
Built-in Pipes: uppercase, lowercase, date, currency.
Custom Pipes: User-defined transformations.
Answer: NgZone is used to optimize performance by running specific tasks outside of Angular’s zone, preventing unnecessary change detection cycles.
Answer: Angular Guards protect routes and control access to components. Types include:
CanActivate: Prevents unauthorized access.
CanDeactivate: Prevents users from leaving unsaved changes.
Resolve: Prefetches data before navigation.
Mastering these Angular JavaScript interview questions will help you confidently tackle interviews for Angular roles, whether you’re a beginner or an expert. Keep practicing, build projects, and stay updated with the latest Angular advancements.