In AngularJS, the ng-click directive is commonly used to handle DOM events in controllers. The ng-click directive allows you to specify a function in the controller that should be executed when a particular DOM element is clicked. This directive simplifies the process of attaching event handlers to HTML elements, making it easier to handle user interactions in AngularJS applications.

Directives in AngularJS are crucial for separating the view logic from the DOM manipulation code. Directives extend HTML with custom attributes and elements, allowing you to create reusable components and encapsulate view-related behavior. They play a key role in enhancing code modularity and maintainability in AngularJS applications. A solid understanding of directives is essential for developers working with complex and dynamic user interfaces.

When an AngularJS expression contains a syntax error, the application throws an error, and the entire page may crash. It is important to handle and fix syntax errors promptly to ensure the smooth functioning of the AngularJS application. Proper error handling is crucial for debugging and maintaining code integrity.

In React, props (short for "properties") are a component's input data that are passed down from a parent component. Props are read-only and cannot be changed by the child component. Props are used to customize the behavior and appearance of a component.

React has several major features, including a virtual DOM, server-side rendering, and component reusability. The virtual DOM helps improve performance by minimizing the number of updates needed to the actual DOM. Server-side rendering allows React to render components on the server before sending them to the client, improving performance and SEO. Component reusability allows developers to create reusable UI components using JavaScript. One-way data binding is not a major feature of React.

React Hooks were introduced to provide an alternative way of managing state and lifecycle methods in functional components. However, class components are still fully supported in React, and you can continue to use them if they are working for your project.

In React, you can add Google Analytics for React Router by using the "react-ga" library with the "react-router-ga" package. This will allow you to track pageviews and events for your React Router pages in Google Analytics, and can be configured in the "index.js" or "App.js" files.

Controlled components are components that store their state in a parent component and are updated using the setState() method. The parent component passes down the component's state as props and also passes down a function to update the state when needed. This approach allows for more control over the component's behavior and simplifies debugging.

In plain React, you can use async/await to handle asynchronous operations like API calls or Promises. Async/await is a feature of ECMAScript 2017, and can be used with modern browsers or transpiled code. However, you may need to use a library or framework like Redux or Apollo to manage the async state and data flow in your application.

React is a library for creating components and managing the state and events of those components, while ReactDOM is a library for rendering those components to the DOM. React provides the programming interface for working with components, while ReactDOM provides the methods for rendering and updating the components in the browser.