What are component lifecycle methods? List the main ones.

Component lifecycle methods are special functions that are called at different stages of a component's existence in the UI. They allow managing state, performing side effects, and optimizing performance.

The main lifecycle methods in React (class components) include:

• constructor — component initialization.
• componentDidMount — called after the component is mounted, suitable for data loading.
• shouldComponentUpdate — controls whether the component should re-render.
• componentDidUpdate — called after the component updates.
• componentWillUnmount — resource cleanup before the component is removed.

In functional components, these stages are implemented through hooks, such as useEffect.