React

useEffect Hook in React

Synchronize with external systems: fetch, subscriptions, timers, DOM APIs.

August 21, 2026 By malekimtiyajmca@gmail.com 1 min read

useEffect Hook in React — a practical guide to React useEffect with clear examples you can reuse in real projects.

React Tutorial Series (29/103). Prefer one article? Read the complete React tutorial.

Short description

Declare dependencies correctly; clean up subscriptions in the return function.

useEffect

useEffect(() => {
  const id = setInterval(() => setNow(Date.now()), 1000);
  return () => clearInterval(id);
}, []);