Directives in AngularJS play a pivotal role in dynamic view manipulation. They allow the creation of custom HTML tags and attributes, enabling developers to extend HTML syntax and create reusable components. By attaching behavior to elements, directives facilitate dynamic updates to the DOM, enhancing the flexibility and maintainability of AngularJS applications. Understanding the role of directives is essential for effective front-end development in AngularJS.

Controllers in AngularJS can communicate with each other using the $scope.$emit and $scope.$on methods. $scope.$emit is used to broadcast an event upwards through the scope hierarchy, and $scope.$on is used to listen for and handle the emitted event. This mechanism allows controllers to exchange information and coordinate actions in a loosely coupled manner. Understanding this communication pattern is important for building modular and reusable AngularJS components.

The $digest function can be used in AngularJS controllers to manually initiate a digest cycle for data binding. The digest cycle is the process by which AngularJS detects changes in the model and updates the view accordingly. Manually invoking $digest is useful in scenarios where automatic detection may not occur, ensuring that changes are reflected in the UI.

To dynamically change the layout of a web page in response to user interactions, you would use the AngularJS directive ng-switch. The ng-switch directive allows you to conditionally render content based on a specified expression, enabling you to switch between different layouts depending on user input. Understanding how to leverage ng-switch for conditional layouts is essential for creating dynamic and responsive user interfaces in AngularJS applications.

In AngularJS, when data in the model changes, the two-way data binding automatically updates the Template to reflect these changes. The template is the HTML representation that binds to the model using directives like ng-model. This automatic update ensures that the user interface stays synchronized with the underlying data, enhancing the responsiveness of AngularJS applications. Understanding the role of the template is crucial for effective implementation of two-way data binding in AngularJS.

In AngularJS, two-way data binding is a common practice to handle DOM events and update the model accordingly. Two-way data binding establishes a synchronization between the model and the view, allowing changes in one to automatically reflect in the other. This simplifies the process of handling user input and keeping the application state in sync with the user interface. Understanding two-way data binding is fundamental to effective data management in AngularJS.

In AngularJS, when two controllers need to communicate, you can use the $broadcast and $on features. $broadcast sends an event downward to all child scopes, and $on listens for these events. This allows controllers to exchange information without being directly connected. Understanding this mechanism is crucial for implementing efficient communication between controllers in AngularJS applications.

AngularJS expressions have limitations compared to standard JavaScript expressions, including limited access to global objects. Due to security reasons, AngularJS expressions do not have direct access to the global window object or other global variables. Developers should be aware of these limitations when working with expressions in AngularJS and use them judiciously to maintain a secure and efficient application.

In MVC architecture, the Controller component is responsible for handling user interactions and managing the flow of data between the Model and View.

Integrating with an external WebSocket API in AngularJS is advantageous because it reduces the need for constant polling. WebSockets enable bidirectional communication between the client and server, allowing real-time data updates. This leads to a more responsive and efficient application, particularly in scenarios where timely updates are critical, such as live chat applications or financial dashboards.