How does React batch state updates?
PICTURE THIS: JAVASCRIPT EVENT LOOP
Simple meaning
React 18 batches setState in timeouts, promises, and native events so one event loop turn can become one render.
WHY — React instead of guessing?
Why interviewers care about React:
question about React.
trade-offs, and what you would actually do on a Frontend project - not buzzwords.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1React 18 batches setState
in timeouts, promises, and native events so one event loop turn can become one render.
- 2Why it exists
That avoids extra paints.
- 3If I need to
read the latest state I use the functional updater, not a variable I just set.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
React 18 batches setState in timeouts, promises, and native events so one event loop turn can become one render. That avoids extra paints.