[Suggestion]: Section "Queueing a Series of State Updates": await in event handler cause immediate rerender
Nobody has claimed this yet.
- Dominant language
- JavaScript
- Stars
- 11.8k
- Forks
- 7.9k
- Avg merge
- 1d 11h
- Merged PRs (30d)
- 11
Description
Summary
The documentation says here: "React waits until all code in the event handlers has run before processing your state updates"
This not the case when using await inside the handler!
Example
const [myNumber, setMyNumber] = useState(0);
async function handleClick(){
setMyNumber(i => i + 1);
await delay(100);
setMyNumber(i => i + 1);
}
function delay(ms) {
return new Promise(resolve => {
setTimeout(resolve, ms);
});
}
This will rerender the component twice!
Page
https://react.dev/learn/queueing-a-series-of-state-updates
Details
I suggest it should be mentioned as caveat/pitfall that if you call await inside an event handler,
all changes made to states before that await will then be flushed and trigger a rerender immediately, not waiting
for the event handler to finish completely.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Read the “Queueing a Series of State Updates” page linked in the issue and reproduce the provided async event-handler example to confirm the behavior. Update that page with a caveat explaining that state updates before an await can flush before the handler finishes; done means the example and batching guidance are accurate and clear.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- javascript, react
- Domain
- documentation
- Issue type
- Documentation
- Difficulty
- 1/5
- Estimated time
- Under an hour
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 55/100