AngularJS is a popular JavaScript framework used for building dynamic and robust web applications. As a result, many developers seek to enhance their skills and knowledge in this area. One way to do so is by preparing for AngularJS interview questions. In this article, we will explore some common AngularJS interview questions that can help you stand out in your job interviews.
1. What is AngularJS, and why is it used for web development?
AngularJS is an open-source JavaScript framework developed by Google. It is used for building single-page applications that are fast, scalable, and maintainable. The primary reason for using AngularJS is its two-way data binding feature, which simplifies the development process by reducing the amount of code required to create interactive web applications.
2. Explain the difference between AngularJS and Angular.
AngularJS and Angular are both developed by Google, but they are different frameworks. AngularJS is a JavaScript library that extends HTML with new attributes, while Angular is a full-fledged MVC (Model-View-Controller) framework built on TypeScript. Angular offers more features and better performance compared to AngularJS, but AngularJS is still widely used in many projects.
3. What is the purpose of ng-model in AngularJS?
Ng-model is an AngularJS directive that creates a two-way data binding between the model and the view. This means that any changes made to the model will automatically reflect in the view, and vice versa. Ng-model is used to bind form controls to data, making it easier to handle user input and update the application’s state.
4. How does AngularJS handle routing?
AngularJS uses the $routeProvider service to handle routing. This service defines the routes for the application and their corresponding controllers. When a user navigates to a specific URL, AngularJS uses the $route service to find the corresponding route and controller, and then initializes the controller and updates the view accordingly.
5. What are the advantages of using AngularJS services?
AngularJS services are a way to encapsulate and reuse code. They provide a way to create singletons that can be injected into controllers, directives, and other services. Some advantages of using AngularJS services include:
– Encapsulation: Services can encapsulate complex logic and keep controllers and directives clean.
– Reusability: Services can be reused across different parts of the application.
– Dependency Injection: Services can be easily injected into other components, making the code more modular and testable.
6. How does AngularJS handle form validation?
AngularJS provides a powerful form validation system using directives like ng-model, ng-minlength, ng-maxlength, ng-pattern, and ng-required. These directives can be applied to form inputs to enforce specific validation rules. Additionally, AngularJS provides custom validation methods that can be defined using the $validator service.
7. What is the difference between $scope and $rootScope in AngularJS?
The $scope is an object that represents the scope of a particular controller. It is used to share data between the controller and the view. The $rootScope is the root scope of the application and is accessible from any controller or directive. It is used to share data across different scopes and components.
8. How does AngularJS handle asynchronous operations?
AngularJS uses the $http service to handle asynchronous HTTP requests. This service allows developers to make AJAX calls and handle responses using callbacks, promises, or the $q service. The $timeout service is also used to perform asynchronous operations like delayed execution or timeout handling.
9. What are the key differences between AngularJS and Angular 2+?
Angular 2+ is a complete rewrite of AngularJS, with a different architecture and design philosophy. Some key differences include:
– TypeScript: Angular 2+ is built on TypeScript, while AngularJS uses plain JavaScript.
– Component-based architecture: Angular 2+ uses a component-based architecture, while AngularJS uses directives and controllers.
– Dependency Injection: Angular 2+ has a more robust dependency injection system.
– Performance: Angular 2+ offers better performance compared to AngularJS.
10. How can you optimize AngularJS applications?
Optimizing AngularJS applications involves several best practices, such as:
– Minimizing the use of $scope: Avoid using $scope for data binding and instead use services and directives.
– Lazy loading: Load modules and components on demand to reduce the initial load time.
– Using filters and pipes: Use filters and pipes to transform data instead of creating complex controllers.
– Optimizing templates: Write efficient templates by using built-in directives and minimizing the use of ng-repeat.
By familiarizing yourself with these AngularJS interview questions and their answers, you can better prepare for your next job interview and showcase your expertise in this popular JavaScript framework.
