What is the lifecycle of a React functional component?

In React, functional components do not have lifecycle methods like class components, but you can use React’s hooks to simulate lifecycle behavior. Here are some commonly used hooks.

1. The useEffect hook is used to perform side effects after the component has been rendered. You can specify a dependency array to execute the side effect when the dependencies change.
2. useState is utilized for adding state in functional components. The state value and methods for updating the state can be obtained through destructuring.
3. useMemo: Cache the computed result during the component rendering process, and only recalculate when the values in the dependency array change.
4. useCallback: a function used for caching, only recreates the function when the values in the dependency array change.
5. useContext: used to access the React context.
6. useReducer encapsulates the state of a component and its method for updating the state into a single function, used for managing complex state logic.

It is important to note that the lifecycle functions of functional components will run every time the component is rendered, rather than only in specific lifecycle stages. This could potentially cause performance issues, so it is important to use a dependency array to control when side effects are executed.