React components go through a lifecycle with three main phases: Mounting, Updating, and Unmounting.
- Mounting: This phase occurs once when a component is first created and inserted into the DOM. It's where you set up initial state and perform one-time setup.
- Updating: This phase is triggered whenever a component's props or state change, causing it to re-render. It's about responding to new data and ensuring the UI reflects the latest information.
- Unmounting: This phase happens when a component is removed from the DOM. It's crucial for cleanup tasks, such as canceling subscriptions or timers, to prevent memory leaks.
The useEffect hook is commonly used to manage side effects across these phases. When used with an empty dependency array ([]), it mimics the mounting and unmounting phases. When dependencies are provided, it runs after the initial mount and after any update where those dependencies have changed.
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