Angular.js Interview Questions and Answers for freshers

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AngularJS Interview Questions for Freshers

  1. What is AngularJS?

    • Answer: AngularJS is a structural framework for dynamic web apps. It lets you use HTML as your template language and lets you extend HTML's syntax to express your application's components clearly and succinctly. It's a JavaScript-based open-source front-end web application framework mainly maintained by Google and by a community of individuals and corporations to address many of the challenges encountered in developing single-page applications.

  2. What are the key features of AngularJS?

    • Answer: Key features include: Data binding, Dependency Injection, Directives, Templating, MVC architecture, Routing, Testing, and RESTful API handling.

  3. Explain data binding in AngularJS.

    • Answer: Data binding is the automatic synchronization of data between the model and the view. Changes in the model automatically update the view, and vice-versa. AngularJS supports two-way data binding, meaning changes in either the model or the view are reflected in the other.

  4. What is a directive in AngularJS? Give examples.

    • Answer: Directives extend HTML with custom attributes, elements, and CSS classes. They allow you to create reusable components. Examples include `ng-model`, `ng-repeat`, `ng-if`, `ng-bind`, and custom directives you create.

  5. Explain the concept of dependency injection in AngularJS.

    • Answer: Dependency Injection is a design pattern where components receive their dependencies from external sources rather than creating them themselves. This promotes loose coupling, testability, and reusability.

  6. What is the difference between ng-model and ng-bind?

    • Answer: `ng-model` creates two-way data binding, while `ng-bind` creates one-way data binding. `ng-model` updates the model when the view changes and vice-versa, whereas `ng-bind` only updates the view when the model changes.

  7. What is an AngularJS expression?

    • Answer: An AngularJS expression is a JavaScript-like code snippet that is evaluated within the AngularJS context. It is used to display data, perform calculations, and manipulate the DOM.

  8. Explain the concept of scope in AngularJS.

    • Answer: A scope is an object that refers to the application model. It acts as a bridge between the controller and the view. It allows data to flow between the controller and the view using data binding.

  9. What is an AngularJS controller?

    • Answer: A controller is a JavaScript function that is used to control the data and logic associated with a specific view. It manipulates the scope to update the view and respond to user interactions.

  10. How do you create a custom directive in AngularJS?

    • Answer: You create a custom directive by defining a function and registering it with the AngularJS module using the `directive` method. The function receives a `compile` and a `link` function (or just a link function) to manipulate the DOM.

  11. What are filters in AngularJS and how are they used?

    • Answer: Filters format data for display in the view. They take input data and transform it before displaying it. Examples include `currency`, `date`, `lowercase`, `uppercase`, and `orderBy`.

  12. Explain AngularJS services.

    • Answer: Services are singleton objects that provide specific functionality to controllers and other parts of the application. They promote modularity and reusability.

  13. What is the difference between $http and $resource services?

    • Answer: Both are used for making HTTP requests. `$http` is a more general-purpose service, while `$resource` provides a higher-level abstraction for interacting with RESTful APIs.

  14. What is routing in AngularJS?

    • Answer: Routing allows you to create single-page applications with multiple views. The `$routeProvider` allows you to define different routes that map URLs to specific views and controllers.

  15. Explain the concept of promises in AngularJS.

    • Answer: Promises represent the eventual result of an asynchronous operation. They handle asynchronous code more elegantly than callbacks, improving readability and maintainability.

  16. How do you perform unit testing in AngularJS?

    • Answer: AngularJS encourages unit testing using frameworks like Jasmine and Karma. You test individual components (controllers, services, directives) in isolation to ensure they work correctly.

  17. What are the advantages of using AngularJS?

    • Answer: Advantages include: two-way data binding, MVC architecture, dependency injection, testability, large community support, and extensive documentation.

  18. What are the disadvantages of using AngularJS?

    • Answer: Disadvantages include: can be verbose, steep learning curve for beginners, and the framework is now considered legacy (AngularJS 1.x) compared to Angular 2+.

  19. Explain the difference between AngularJS and Angular (Angular 2+).

    • Answer: AngularJS (Angular 1.x) and Angular (2+) are distinct frameworks. Angular is a complete rewrite with TypeScript support, improved performance, and a component-based architecture, while AngularJS uses JavaScript and has a different architecture.

  20. How do you handle events in AngularJS?

    • Answer: Events are handled using directives like `ng-click`, `ng-submit`, `ng-change`, etc., or by using event listeners within controllers and directives.

  21. What is the role of the $scope.$apply() method?

    • Answer: `$scope.$apply()` is used to execute code within the AngularJS context. It's crucial when updating the scope from outside of Angular's digest cycle (e.g., from a timer or a third-party library).

  22. How do you create a reusable component in AngularJS?

    • Answer: Reusable components are typically created using custom directives, combining templates, controllers, and linking functions to encapsulate functionality and data.

  23. Explain the concept of modules in AngularJS.

    • Answer: Modules are containers for organizing controllers, services, directives, and other components. They help structure your application and manage dependencies between different parts.

  24. How do you include AngularJS in your HTML page?

    • Answer: You include AngularJS by adding a `