React Hooks were introduced based on community proposals and discussions, as well as official React documentation and blog posts. They were also presented and discussed at React conferences and meetups.

Portals in React provide a way to render a component's children in a different part of the DOM. This can be useful for creating modal dialogs, tooltips, and other UI components that need to be positioned outside the normal flow of the page.

In React, an element is a plain JavaScript object that represents a single HTML element. A component, on the other hand, is a function or class that returns an element (or multiple elements). Components are used to create reusable UI elements, while elements are used to represent the actual DOM elements that make up the UI.

In React Router v4, you can programmatically navigate by using the "history" object provided by the router. To navigate to a new route, you can use the "this.props.history.push" method with a route path as a string. This method adds a new entry to the history stack and navigates to the specified route. For example: this.props.history.push('/new-route');.

In Create React App, you can use HTTPS instead of HTTP by setting the "HTTPS=true" environment variable. This will start the development server with HTTPS enabled, and will allow you to test your application with SSL/TLS encryption.

In React, the "setState" method is used to update component state, and it merges the new state with the old state. The "replaceState" method is similar, but it overwrites the old state completely with the new state. However, "replaceState" is deprecated in React and should not be used. Instead, you should use the "setState" method to update state in a React component.

The ref argument is only available for class components in React. Function components do not have an instance, so refs cannot be attached to them. Refs can be attached to DOM elements, class components, and functional components that are created using the forwardRef() method.

Whether or not to use Redux to manage state in a React application depends on the complexity and size of the application. For small and simple applications, it may be sufficient to use React's internal state management. However, for larger and more complex applications, Redux can be a helpful tool for managing application state.

Stateful components, also known as class components, are components that maintain state. Stateful components are useful for creating more complex UI components that need to maintain state, but they are more difficult to test than stateless components.

In React Router v4, you can get query parameters by using the "location.search" property of the current location object. This property contains the query string of the URL, including the "?" character and the parameter keys and values. To parse the query string, you can use a library like "query-string" or "URLSearchParams". For example: const queryParams = new URLSearchParams(this.props.location.search); const foo = queryParams.get('foo');.

React lazy is a function that creates a lazy version of a component. This lazy version is loaded only when it is actually needed, such as when a user navigates to a page that requires the component. This can help improve performance by reducing the initial load time of the application.

ReactDOMServer is a module that allows you to render React components on the server. ReactDOMServer provides several methods for rendering components, including the renderToString method and the renderToStaticMarkup method.