react-useeffect

Use useEffect for synchronizing React components with external systems, handling subscriptions, and data fetching. Avoid React useEffect for transforming state or deriving values during render to prevent common anti-patterns and unnecessary effects.

To clean up subscriptions in a React useEffect hook, return a cleanup function from the effect. This cleanup strategy prevents memory leaks by properly removing event listeners or canceling ongoing external synchronization when the component unmounts.

The best way to fetch data with React useEffect is to implement proper cleanup functions that cancel ongoing requests. This best practice prevents race conditions and ensures safe effects by ignoring stale responses during component lifecycles.

Avoid useEffect for transforming data or reacting to user events; use event handlers instead. For expensive calculations, use useMemo. For external store subscriptions, useSyncExternalStore is the recommended alternative to prevent anti-patterns.

React useEffect interacts with useState by triggering side effects when state updates occur across component lifecycles. However, combining them for derived state is an anti-pattern; compute values during render or use useMemo instead of useEffect.

Yes, you can use useMemo instead of useEffect for state calculations. useMemo is the recommended alternative for caching expensive calculations during render, avoiding the unnecessary effects and anti-patterns caused by forcing derived state through useEffect.