When not to use
- If you can calculate something during render, you don’t need an Effect.
- To cache expensive calculations, add
useMemo instead of useEffect.
- To reset the state of an entire component tree, pass a different
key to it.
- To reset a particular bit of state in response to a prop change, set it during rendering.
- Code that runs because a component was displayed should be in Effects, the rest should be in events.
- If you need to update the state of several components, it’s better to do it during a single event.
- Whenever you try to synchronize state variables in different components, consider lifting state up.
- You can fetch data with Effects, but you need to implement cleanup to avoid race conditions.
Sources