Angular.js Interview Questions and Answers for internship

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AngularJS Internship Interview Questions and Answers

  1. What is AngularJS?

    • Answer: AngularJS is 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. It allows developers to use HTML as the template language and extends HTML's syntax to express the application's components clearly and succinctly.

  2. What are the key features of AngularJS?

    • Answer: Key features include: MVC architecture, two-way data binding, dependency injection, directives, templating, routing, and testing capabilities.

  3. Explain the MVC architecture in AngularJS.

    • Answer: AngularJS follows the Model-View-Controller (MVC) architectural pattern. The Model represents the data, the View displays the data, and the Controller acts as an intermediary between the Model and the View, handling user interactions and updating the data accordingly.

  4. What is two-way data binding in AngularJS?

    • Answer: Two-way data binding automatically synchronizes data between the model and the view. Any changes made in the model are reflected in the view, and vice-versa. This simplifies development and reduces the need for manual synchronization.

  5. Explain dependency injection in AngularJS.

    • Answer: Dependency Injection is a design pattern where dependencies are provided to a component instead of the component creating them. This promotes modularity, testability, and reusability.

  6. What are directives in AngularJS? Give examples.

    • Answer: Directives extend HTML with custom attributes, elements, and CSS classes. Examples include `ng-model`, `ng-repeat`, `ng-if`, `ng-bind`, and custom directives created by developers.

  7. What is the purpose of the `ng-model` directive?

    • Answer: `ng-model` creates a two-way data binding between the view (input field) and the model (scope variable). Changes in the input field update the model, and changes in the model update the input field.

  8. What is the purpose of the `ng-repeat` directive?

    • Answer: `ng-repeat` iterates over a collection (array or object) and dynamically creates a new HTML element for each item in the collection.

  9. What is the purpose of the `ng-if` directive?

    • Answer: `ng-if` conditionally renders an HTML element based on the truthiness of an expression. If the expression is true, the element is rendered; otherwise, it is removed from the DOM.

  10. What is the purpose of the `ng-bind` directive?

    • Answer: `ng-bind` replaces the content of an HTML element with the value of a model (scope variable). It's similar to using interpolation `{{expression}}` but offers better performance in some cases.

  11. Explain AngularJS scopes.

    • Answer: Scopes are objects that act as bridges between controllers and views. They hold application data and provide context for expressions within templates. AngularJS uses a hierarchical scope structure.

  12. What is a controller in AngularJS?

    • Answer: A controller is a JavaScript function that is responsible for handling user interactions and updating the model. It acts as the glue between the view and the model.

  13. Explain AngularJS services.

    • Answer: Services are singleton objects that provide specific functionalities to controllers and other parts of the application. They promote code reusability and separation of concerns.

  14. How do you create a service in AngularJS?

    • Answer: Services can be created using the `service`, `factory`, `provider`, or `constant` methods.

  15. What is the difference between a service, factory, and provider in AngularJS?

    • Answer: They all create services, but differ in how they are defined and instantiated. `service` uses a constructor function. `factory` returns an object. `provider` allows configuration before instantiation. Choose based on your needs for instantiation and configuration.

  16. What is routing in AngularJS?

    • Answer: Routing allows you to create single-page applications with multiple views. It enables navigation between different views without reloading the entire page.

  17. How do you implement routing in AngularJS?

    • Answer: Routing is implemented using the `ngRoute` module and the `$routeProvider` service. You define routes that map URLs to specific views and controllers.

  18. What are filters in AngularJS? Give examples.

    • Answer: Filters format data for display in the view. Examples include `date`, `currency`, `lowercase`, `uppercase`, `orderBy`, and custom filters.

  19. How do you create a custom filter in AngularJS?

    • Answer: Custom filters are created using the `filter` method. They take input data and return transformed data.

  20. Explain AngularJS expressions.

    • Answer: Expressions are JavaScript code snippets enclosed in double curly braces `{{expression}}` that are evaluated against the scope and displayed in the view.

  21. What is the difference between AngularJS expressions and JavaScript code?

    • Answer: AngularJS expressions are evaluated against the scope and used primarily for displaying data in the view. They have limited functionality compared to full JavaScript code. JavaScript code is used for more complex logic within controllers and services.

  22. What is the digest cycle in AngularJS?

    • Answer: The digest cycle is the process by which AngularJS detects changes in the model and updates the view accordingly. It compares the old and new values of the model and updates the view if there's a difference.

  23. Explain $http service in AngularJS.

    • Answer: The `$http` service is used to make AJAX calls to communicate with the server. It allows you to send HTTP requests (GET, POST, PUT, DELETE) and handle responses.

  24. How do you handle errors using $http service?

    • Answer: The `$http` service's `then` method allows for success handling, while the `catch` method handles errors. You can check the response status code to determine the type of error.

  25. What are promises in AngularJS?

    • Answer: Promises represent the eventual result of an asynchronous operation. They allow you to handle success and failure callbacks in a cleaner way.

  26. How do you test AngularJS applications?

    • Answer: AngularJS applications can be tested using unit tests (testing individual components) and end-to-end tests (testing the entire application flow). Frameworks like Karma and Jasmine are commonly used.

  27. Explain the concept of $scope.$apply()

    • Answer: `$scope.$apply()` is used to manually trigger the digest cycle. It's necessary when changes to the model occur outside of AngularJS's context, such as in a timeout or an event handler.

  28. What is the difference between `ng-src` and `src`?

    • Answer: `ng-src` is preferred over `src` for dynamic image loading because it prevents the browser from rendering a broken image before AngularJS has a chance to set the correct value.

  29. Explain AngularJS's module system.

    • Answer: AngularJS uses modules to organize code into reusable components. Modules define dependencies and contain controllers, services, directives, etc. They help in structuring larger applications.

  30. What are some common AngularJS best practices?

    • Answer: Best practices include: using dependency injection, writing modular code, keeping controllers lean, using services for reusable logic, testing thoroughly, and following naming conventions.

  31. What are some common AngularJS pitfalls to avoid?

    • Answer: Pitfalls include: overusing scopes, creating overly complex controllers, neglecting testing, improper error handling, and inefficient use of directives.

  32. How do you handle asynchronous operations in AngularJS?

    • Answer: Asynchronous operations are handled using promises or callbacks. The `$http` service returns a promise, and you can chain `.then` and `.catch` for success and error handling.

  33. How do you debug AngularJS applications?

    • Answer: Use your browser's developer tools (console, debugger) to inspect variables, set breakpoints, and examine the execution flow. AngularJS provides tools for debugging scopes and other elements.

  34. What is the difference between AngularJS and Angular (Angular 2+)?

    • Answer: AngularJS is based on JavaScript, while Angular (2+) is based on TypeScript. Angular (2+) is a completely rewritten framework with improved performance, architecture, and features. They are not compatible.

  35. What are some limitations of AngularJS?

    • Answer: Limitations include performance issues with large applications, digest cycle overhead, and the complexity of managing scopes in large projects. This led to the development of Angular 2+.

  36. Explain how to use $location service in AngularJS.

    • Answer: The `$location` service provides information about the current URL and allows you to manipulate it programmatically. You can use it to get the current path, search parameters, and hash fragments.

  37. How to handle events in AngularJS?

    • Answer: Events can be handled using directives such as `ng-click`, `ng-change`, `ng-submit`, etc. For custom events, use `$emit`, `$broadcast`, and `$on` methods to handle event propagation between scopes.

  38. Explain the concept of watchers in AngularJS.

    • Answer: Watchers are used to monitor changes in model values. When a watched value changes, AngularJS executes a callback function. They are crucial for two-way data binding but can impact performance if overused.

  39. Describe your experience with AngularJS project(s).

    • Answer: (This requires a personalized answer based on your experience. Mention specific projects, roles, technologies used, and challenges overcome.)

  40. What are some of the challenges you faced while working with AngularJS?

    • Answer: (This requires a personalized answer based on your experience. Mention specific challenges and how you overcame them.)

  41. How do you stay updated with the latest trends in AngularJS (or front-end development in general)?

    • Answer: (This requires a personalized answer. Mention specific resources, such as blogs, websites, conferences, newsletters, etc.)

  42. Why are you interested in this internship?

    • Answer: (This requires a personalized answer. Mention specific reasons, such as the company's mission, the project's scope, and your career goals.)

  43. What are your strengths and weaknesses?

    • Answer: (This requires a personalized answer. Be honest and focus on relevant skills.)

  44. Tell me about a time you faced a challenging problem and how you solved it.

    • Answer: (This requires a personalized answer. Use the STAR method: Situation, Task, Action, Result.)

  45. Tell me about a time you worked on a team project. What was your role?

    • Answer: (This requires a personalized answer. Describe your contributions and how you collaborated with others.)

  46. Where do you see yourself in 5 years?

    • Answer: (This requires a personalized answer. Be realistic and show ambition.)

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