Which stages or methods of the React component lifecycle are not available for implementation in functional components?

Functional React components do not have lifecycle methods like class components, such as:

• componentDidMount
• componentDidUpdate
• componentWillUnmount
• shouldComponentUpdate
• getDerivedStateFromProps
• componentDidCatch

Instead, hooks are used, for example, useEffect allows implementing logic similar to componentDidMount, componentDidUpdate, and componentWillUnmount.

However, some methods, such as shouldComponentUpdate (for rendering optimization), are not directly implemented, but React.memo can be used for memoization of functional components.

Thus, there are no direct lifecycle methods in functional components, but their behavior is achieved through hooks and auxiliary functions.