New 100 Angular JS Interview Question

Introduction

AngularJS is a popular JavaScript framework developed by Google for building dynamic web applications. If you’re preparing for an AngularJS interview, it’s essential to have a good understanding of the framework and its key concepts. This user-friendly introduction to AngularJS interview questions will help you grasp the basics and prepare for a successful interview.

AngularJS offers several advantages that make it a preferred choice for web development:

1. Two-way data binding: AngularJS provides automatic synchronization between the model (data) and the view (UI), eliminating the need for manual DOM manipulation.
2. Modular architecture: AngularJS promotes modular development through components, directives, and services, making it easier to manage and scale complex applications.
3. Dependency injection: With AngularJS, you can easily inject dependencies into components, enabling better code organization, testability, and reusability.
4. Reusable components: AngularJS allows you to create reusable components that encapsulate functionality and can be easily used across multiple parts of an application.
5. Declarative templates: AngularJS uses HTML-based templates to define the UI, making it easier to understand and maintain the structure of your application.
6. Powerful data manipulation: AngularJS provides built-in filters and directives for manipulating and formatting data, simplifying common tasks such as sorting, filtering, and data binding.

The AngularJS interview questions covered here are suitable for individuals with varying levels of experience, including:

1. Beginners: If you’re new to AngularJS, these questions will help you gain a fundamental understanding of the framework and its core concepts.
2. Intermediate Developers: If you have some experience with AngularJS and want to expand your knowledge, these questions will help you delve deeper into advanced topics and best practices.
3. Experienced Developers: Even if you’re already proficient in AngularJS, these interview questions can serve as a valuable refresher and help you solidify your understanding of key concepts.

Whether you’re preparing for an entry-level AngularJS interview or aiming for a senior developer role, these questions will cover a range of topics to enhance your knowledge and boost your confidence during the interview process. Remember to practice implementing code examples and explanations to reinforce your understanding. Good luck with your AngularJS interview preparation!

Basic Questions

1. What is Angular JS?

AngularJS is a JavaScript-based open-source front-end web application framework developed by Google. It allows developers to build dynamic web applications by extending the functionality of HTML and providing a structured approach to application development. AngularJS follows the model-view-controller (MVC) architectural pattern and provides a set of tools and features for building single-page applications.

2. What are the key features of Angular JS?

• Two-way data binding
• Directives for extending HTML syntax
• Dependency injection for managing components
• Templating and declarative user interface
• Modular structure with reusable components
• Routing for building single-page applications
• Testing support with unit testing and end-to-end testing frameworks
• AJAX and RESTful API integration
• Form validation and error handling
• Internationalization and localization support

3. What are the advantages of using Angular JS?

• Enhanced productivity with declarative code and reusable components
• Two-way data binding simplifies the synchronization between UI and data models
• Modular architecture promotes code organization and maintainability
• Dependency injection enables easier testing and component isolation
• Powerful built-in features for form validation and error handling
• Efficient data binding and change detection mechanism
• Large and active community support with extensive documentation
• Seamless integration with other libraries and frameworks
• Improved performance through optimized rendering and caching

4. How does data binding work in Angular JS?

Data binding in AngularJS allows automatic synchronization of data between the model and the view. There are two types of data binding:

• One-way data binding: Changes in the model (JavaScript variables) are reflected in the view (HTML), but not vice versa. It is denoted by {{ expression }} in HTML templates.
  Example: <span>{{ message }}</span>
• Two-way data binding: Changes in the model are immediately propagated to the view, and vice versa. It uses the ng-model directive for two-way binding.
  Example: <input type="text" ng-model="name">

AngularJS uses a dirty checking mechanism to detect changes in the model and update the view accordingly. When a user interacts with the UI, the changes are automatically propagated to the model and vice versa, ensuring synchronization between the two.

5. Explain the concept of directives in Angular JS.

Directives in AngularJS are markers or attributes added to HTML elements that extend the functionality of HTML and define reusable components. They allow developers to create custom HTML tags and attributes, manipulate the DOM, attach behavior to elements, and encapsulate complex UI logic.

Directives can be used for various purposes, such as data binding, event handling, manipulating the DOM, rendering dynamic content, and creating reusable components.

Example of a directive usage:

<my-directive></my-directive>

AngularJS provides several built-in directives like ng-model, ng-repeat, ng-if, etc., and allows developers to create custom directives to suit specific application requirements.

6. What is dependency injection in Angular JS?

Dependency injection (DI) in AngularJS is a design pattern that allows components to be loosely coupled and makes it easier to manage dependencies between them. In DI, the dependencies of a component are provided from external sources, rather than being created within the component itself.

AngularJS provides an injector subsystem that resolves and injects dependencies automatically. Components declare their dependencies, and the injector takes care of providing the required dependencies when the component is instantiated.

Example of dependency injection in a controller:

app.controller('MyController', ['$scope', 'userService', function($scope, userService) {
  // $scope and userService are injected dependencies
  // Controller logic goes here
}]);

Dependency injection promotes modular and reusable code, improves testability, and enables easier component isolation and substitution.

7. How do you create a controller in Angular JS?

In AngularJS, controllers are used to define the behavior and logic of a specific part of the application. To create a controller, follow these steps:

1. Define the controller function and its logic:

app.controller('MyController', ['$scope', function($scope) {
  // Controller logic goes here
}]);

2. Attach the controller to a specific HTML element using the ng-controller directive: