Top 150 Angular Interview Questions and Answers

A module in Angular is defined using the NgModule decorator.

• Import the NgModule decorator from @angular/core

• Use the decorator to define the module and its properties

• Export the module to make it available for other modules to import

Angular is a JavaScript framework for building web applications.

• Uses TypeScript for building scalable and maintainable applications

• Provides two-way data binding for easy synchronization between model and view

• Offers a powerful set of built-in directiv...read more

React JS is a lightweight library for building user interfaces, while Angular is a full-fledged framework with more features.

• React is more flexible and allows for easier integration with other libraries and frameworks.

• Angular provides more out-of-the...read more

To create a service in Angular, you can use the 'ng generate service' command or manually create a service file.

• Use the Angular CLI command 'ng generate service serviceName' to create a new service file

• Manually create a service file by creating a new...read more

To call an API in Angular, use HttpClient module to make HTTP requests.

• Import HttpClientModule in app.module.ts

• Inject HttpClient in the component/service where API call needs to be made

• Use HttpClient methods like get(), post(), put(), delete() to mak...read more

The application would not work properly without @NgModule as it is required to bootstrap the application and configure dependencies.

• Without @NgModule, the application would not be able to bootstrap and start properly.

• NgModule is used to configure dep...read more

Server-side rendering (SSR) in Angular can be enabled by using Angular Universal.

• Install Angular Universal using Angular CLI

• Create a new Angular Universal project

• Update app.module.ts to include server-side rendering

• Build and run the Angular Universal...read more

A module is a container for a group of related components, directives, pipes, and services.

• Modules help organize an application into cohesive blocks of functionality.

• They can be imported and exported to share functionality between modules.

• Angular has...read more

Angular lifecycle hooks are methods that allow you to tap into specific points in a component's lifecycle.

• ngOnChanges: Called when an input property changes

• ngOnInit: Called once the component is initialized

• ngDoCheck: Called during every change detect...read more

Interceptors are used to intercept HTTP requests and responses.

• To add headers, modify requests, or handle errors globally

• Can be used for authentication, logging, caching, etc.

• Example: Adding an authorization token to every request

Route guards are used in Angular to prevent unauthorized access to certain routes.

• Route guards can be used to check if a user is authenticated before allowing access to a route.

• There are three types of route guards: CanActivate, CanActivateChild, and...read more

ActivatedRoute is used to access the current route's information.

• It provides access to route parameters, query parameters, and fragment parameters.

• It can be used to subscribe to route parameter changes.

• It can be injected into a component or service.

• E...read more

NGRX is a state management library for Angular applications, inspired by Redux.

• NGRX helps manage the state of an Angular application in a predictable way

• It uses a unidirectional data flow and immutable state

• NGRX consists of actions, reducers, selecto...read more

Vue is lightweight and easy to learn, while Angular is more powerful and feature-rich.

• Vue is easier to set up and has a smaller learning curve

• Angular has more built-in features and is better for larger projects

• Vue uses a template-based syntax, while ...read more

Angular 12 is the latest version with updates on Ivy, performance improvements, and new features.

• Angular 12 is the latest version released in May 2021

• Updates include improvements to Ivy compiler, performance enhancements, and new features like strict...read more

To reduce bundle size of an Angular application, you can use lazy loading, tree shaking, code splitting, and optimizing assets.

• Use lazy loading to load modules only when needed

• Implement tree shaking to remove unused code

• Utilize code splitting to divi...read more

Angular performance improvements involve optimizing code, reducing load times, and minimizing rendering cycles.

• Use lazy loading to only load components when needed

• Optimize change detection by using OnPush strategy

• Minimize DOM manipulation by using ng...read more

Custom hooks in Angular are functions that allow you to reuse logic across multiple components.

• Custom hooks are created using the @Injectable decorator

• They can be used to share stateful logic between components

• They can also be used to abstract away c...read more

ng-container is a structural directive in Angular used to group elements without creating an extra element in the DOM.

• ng-container is used to group elements together without adding an extra element to the DOM

• It is often used with structural directive...read more

Reactive forms are more flexible and allow for complex form validation and handling, while template driven forms are simpler and rely on directives in the template.

• Reactive forms are defined programmatically in the component class using form controls...read more

Creating a drop-down in Angular

• Use the element in HTMLUse *ngFor directive to loop through optionsBind the selected value to a variable using [(ngModel)]Use *ngIf directive to conditionally show/hide the drop-down

Angular is a JavaScript framework for building web applications. SPA came in picture for better user experience.

• Angular is a client-side framework developed by Google.

• It allows developers to build dynamic, single-page web applications.

• SPA (Single Pag...read more

ngClass is used to conditionally apply CSS classes to an element in Angular.

• Use ngClass directive in the template with an object or array of classes and conditions

• Classes are applied when the condition is true, and removed when false

• Example:

To load an Angular application, you can use the Angular CLI command 'ng serve' to start a development server.

• Use the Angular CLI command 'ng serve' to start a development server

• Navigate to the project directory in the terminal and run 'ng serve'

• Open ...read more

Routing guards are used in Angular to control access to certain routes based on certain conditions.

• Routing guards are used to protect routes in Angular applications.

• They can be used to control access based on authentication status, user roles, etc.

• Th...read more

Ngrx Store is a state management library for Angular applications.

• Centralized state management for Angular applications

• Uses RxJS for reactive programming

• Helps manage application state in a predictable way

• Facilitates communication between components

To call a service in Angular, you need to inject the service into a component or another service and then call its methods.

• Inject the service into the component or service constructor

• Call the service method using the injected instance