1. What is AngularJS?
AngularJS is an open-source JavaScript framework developed by Google for building dynamic web applications. It enables developers to use HTML as a template language and extend its syntax to express application components clearly.

2. What are the key features of AngularJS?
Some key features of AngularJS are:
– Two-way data binding
– Directives
– Dependency injection
– MVC architecture
– Templating
– Testing support
– Routing

3. What is two-way data binding in AngularJS?
Two-way data binding is a feature in AngularJS that allows automatic synchronization between the model and the view. When the model changes, the view is automatically updated and vice versa.

4. What are directives in AngularJS?
Directives in AngularJS are markers on a DOM element that extend its functionality or behavior. They can be used to create custom HTML tags, attributes, classes, and comments.

5. What is dependency injection in AngularJS?
Dependency injection is a software design pattern used in AngularJS to manage dependencies between different parts of an application. It helps in creating loosely coupled components and makes code more modular and testable.

6. What is an AngularJS module?
An AngularJS module is a container for different parts of an application, such as controllers, services, filters, directives, etc. It helps in organizing and separating concerns within an application.

7. What is an AngularJS directive and how to create one?
An AngularJS directive is a JavaScript function that can be added to HTML elements as attributes, classes, etc. It allows developers to extend HTML with new functionality. To create a directive, you can use the `directive` method of an AngularJS module.

8. What is the difference between `$rootScope` and `$scope`?
`$rootScope` is the parent scope of all other scopes in an AngularJS application. It is accessible across all controllers, directives, services, etc. On the other hand, `$scope` is specific to a controller or directive and is used to define the model and behavior of that particular component.

9. What is AngularJS template?
An AngularJS template is an HTML file that contains placeholders for dynamically generated content. It can include AngularJS directives to bind data, control flow, and manipulate the DOM.

10. What is the purpose of `$watch` in AngularJS?
The `$watch` function in AngularJS is used to observe changes in model data and trigger a callback function whenever a change is detected. It helps in updating the view automatically when the model changes.

11. What is AngularJS routing and how to implement it?
AngularJS routing allows you to create single-page applications by dynamically changing the content based on the URL. It can be implemented using the `$routeProvider` service provided by the `ngRoute` module.

12. What is data binding in AngularJS?
Data binding in AngularJS is a feature that synchronizes data between the model and the view. It eliminates the need for manual DOM manipulation and keeps the view updated with the latest data.

13. What is the use of `$http` service in AngularJS?
The `$http` service in AngularJS is used to make XMLHttpRequests to a server and retrieve data asynchronously. It provides methods like `get`, `post`, `put`, `delete`, etc., to interact with a RESTful API.

14. How to handle errors in AngularJS?
In AngularJS, you can handle errors using the `$exceptionHandler` service or by defining your own error-handling logic using the `try-catch` block. Additionally, you can also use the `ng-exception` directive to handle exceptions in the view.

15. What is the use of `$routeParams` in AngularJS?
The `$routeParams` service in AngularJS allows you to retrieve the parameters passed in the URL. It is useful when implementing routing and creating dynamic views based on URL parameters.

16. How to handle form validation in AngularJS?
AngularJS provides built-in form validation directives like `ng-required`, `ng-minlength`, `ng-maxlength`, etc., to handle form validation. You can also create custom validation functions and directives to implement complex validation logic.

17. What is AngularJS digest cycle?
The digest cycle in AngularJS is the process of updating the view with the latest model changes. It starts when an event occurs (such as a user input) and triggers the digest loop, which compares the previous and current values of the model and updates the view if necessary.

18. What is the difference between `$apply()` and `$digest()`?
`$apply()` is used to start the AngularJS digest cycle manually. It applies changes to the model and updates the view. On the other hand, `$digest()` triggers the digest cycle explicitly without applying any changes to the model.

19. What is AngularJS filter and how to use it?
AngularJS filters allow you to format, sort, and filter data in the view. They can be used with data bindings, directives, and controllers. Filters are applied using the `|` (pipe) symbol followed by the filter name.

20. How to make AJAX calls in AngularJS?
You can make AJAX calls in AngularJS using the `$http` service or the `$resource` service. The `$http` service provides a simple way to perform AJAX requests, while the `$resource` service is more powerful and can handle RESTful APIs easily.

1. What is AngularJS?
AngularJS is an open-source JavaScript framework developed by Google. It is used to build dynamic web applications.

2. What are the key features of AngularJS?
Some key features of AngularJS include two-way data binding, dependency injection, directives, templates, and testing capabilities.

3. What is two-way data binding in AngularJS?
Two-way data binding in AngularJS allows automatic synchronization between the model and the view. Any changes made in the model are immediately reflected in the view, and vice versa.

4. Explain the concept of dependency injection in AngularJS.
Dependency injection is a design pattern used in AngularJS where the dependencies of a component are provided externally rather than being created internally. It helps in creating loosely coupled and testable components.

5. What are directives in AngularJS?
Directives in AngularJS are markers on a DOM element that tell AngularJS to attach a specific behavior to that element or transform the DOM element and its children.

6. Explain the difference between ng-show and ng-if directives.
The ng-show directive shows or hides an element based on a condition while keeping it in the DOM. The ng-if directive also shows or hides an element based on a condition but removes it from the DOM if the condition is false.

7. What is AngularJS service?
An AngularJS service is a singleton object or function that is available for the entire application. It is used to share data and behavior across different parts of the application.

8. Explain the concept of scopes in AngularJS.
Scopes in AngularJS are objects that bind the view and the model. They act as a glue between the controller and the view, allowing data and functions to be accessed from both sides.

9. What are filters in AngularJS?
Filters in AngularJS are used to manipulate data before displaying it in the view. They can be applied to expressions in the view to format, filter, and sort data.

10. What is $routeProvider in AngularJS?
$routeProvider is a service in AngularJS that provides routing capabilities. It is used to define the routes for different URLs in the application and map them to different templates and controllers.

11. Explain the concept of $http in AngularJS.
$http is a service in AngularJS that allows making AJAX requests to the server. It provides methods like GET, POST, PUT, DELETE to send and receive data from the server.

12. What is ng-model directive in AngularJS?
ng-model is a directive in AngularJS used for two-way data binding. It binds the value of an HTML element to a property in the model.

13. How does AngularJS handle form validation?
AngularJS provides built-in form validation using its ngForm and ngModel directives. It supports both default and custom validation rules.

14. Explain the use of $watch and $digest in AngularJS.
$watch is used to observe changes in a specific property or expression in the scope. $digest is used to trigger the process of checking for changes in the scope and updating the view if necessary.

15. What is the difference between $timeout and setTimeout?
$timeout is a service in AngularJS that provides a wrapper for the setTimeout function in JavaScript. The key difference is that $timeout triggers the digest cycle after the timeout, ensuring that any changes to the scope are reflected in the view.

16. What is ng-bind directive in AngularJS?
ng-bind is a directive in AngularJS used to bind the content of an HTML element to a property in the model. It is similar to the double curly brace notation {{ }}, but it performs better in terms of performance.

17. Explain the concept of $route in AngularJS.
$route is a service in AngularJS that provides routing capabilities. It allows defining different routes in the application and mapping them to different templates and controllers.

18. What is transclusion in AngularJS?
Transclusion is a technique in AngularJS that allows including the content of a directive inside its template. It is useful when you want to create reusable components with customizable content.

19. How can you communicate between controllers in AngularJS?
There are multiple ways to communicate between controllers in AngularJS, such as using a shared service, using events, or using the $rootScope.

20. What is the use of $q service in AngularJS?
$q is a service in AngularJS used for handling asynchronous operations and promises. It provides methods like defer, resolve, and reject to handle async tasks and their results.