To access the Redux store outside of a component, you can use the getState() method provided by the Redux store. This allows you to access the current state of the store and is often used in middleware or in other parts of the application that do not have direct access to the store.

In React, you can make an AJAX call by using the "fetch" API or a library like Axios or jQuery. The recommended lifecycle method to make an AJAX call is "componentDidMount()", which is called once the component has been mounted to the DOM. This method is a good place to fetch data from an API or server, and update the component state with the new data.

Relay is a library for handling data fetching and caching in React applications. It is often used in conjunction with GraphQL APIs. While Redux is a state management library, Relay focuses specifically on data fetching and caching. Relay provides a number of features, such as declarative data requirements, automatic query generation, and optimistic updates.

TestRenderer is a package that allows developers to render React components to a JSON format, making it easier to test and debug components. It is used for snapshot testing and is similar to the ReactTestUtils package.

Uncaught errors in React 16 and later versions trigger a fatal error and crash the application. This behavior was introduced in order to prevent subtle bugs and inconsistencies that could result from errors being silently ignored or logged to the console.

DevTools may not load for local files in Chrome due to the browser's security settings. To fix this issue, you can start Chrome with the --allow-file-access-from-files flag, which disables the security check for local files. Alternatively, you can run the React app on a local web server instead of opening the HTML file directly in the browser.

Redux Form is a library that provides a simple and efficient way to manage forms in Redux applications. It allows you to easily create and manage form components using a simple declarative syntax. Redux Form provides a range of features, including form validation, field normalization, and asynchronous form submission.

To set the initial state in Redux, you can set the initialState property in the reducer function when creating the Redux store. This allows you to set the initial state for the entire Redux store or for a specific slice of the store.

Redux Thunk is a middleware for Redux that allows you to write asynchronous logic that interacts with a Redux store. It enables you to dispatch asynchronous actions, such as API requests, and handle them in a synchronous way.

In React, keys should be globally unique whenever possible. This helps React identify which items have changed, added, or removed from a list, and update the UI accordingly. While keys do not have to be globally unique in all cases, it is generally a best practice to use unique keys whenever possible.