The usePrevious custom hook allows you to access the previous state or props without triggering a re-render. It's not a built-in hook in React but is often implemented as a custom hook. The useEffect hook can be used to achieve similar functionality, but it can indirectly trigger re-renders, making usePrevious a more direct choice for this specific use case.

A potential reason why the error isn't caught by error boundaries is that it originates in a child component of the one wrapped with an error boundary. Error boundaries only catch errors in the component tree below them, not in their parent components. The other options are less likely explanations. Asynchronous errors (Option 1) can still be caught, custom error boundaries (Option 2) can be configured to catch specific errors, and error boundaries can be set up before rendering (Option 4).

React Fragments are useful when you want to group multiple elements without introducing an extra div wrapper. This is beneficial for cleaner and more semantic JSX code. The other options do not directly relate to the use of React Fragments.

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.

A common mistake that can cause a function to be called every time the component renders is declaring the function inside the component's render method. This can cause the function to be recreated every time the component renders, even if the function's dependencies have not changed. To avoid this problem, functions should be declared outside the render method, or in a separate file if they are reused across multiple components.

It is not recommended to keep all component state in the Redux store. While Redux is useful for managing state in large applications, it can also add unnecessary complexity and boilerplate code to small applications. It is recommended to keep only the necessary state in the Redux store and use component state for simpler state management needs.