Clarify event handler error docs

[aurorascharff]

What

Clarifies the docs that useErrorBoundary is useful for event handler errors as well as async callback errors.

Why

React error boundaries do not automatically catch errors from event handlers or async code that runs after render. The previous "async errors" wording was accurate but too narrow, because manually caught event handler errors can also be passed to the nearest boundary.

How

• Rename the relevant docs section and navigation from "async" to "event handler and async" errors.
• Restore the useErrorBoundary example to the common useEffect + rejected fetch pattern.
• Make the effect example recover when username changes and ignore stale request failures after cleanup.
• Keep the React 19 useTransition example focused on a mutation-style Action.
• Regenerate docs, example, and search artifacts.

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Pull request overview

Note

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Updates the “Async user code errors” example and related documentation to emphasize that error boundaries don’t automatically catch errors from event handlers or async callbacks, and demonstrates forwarding those errors to the nearest boundary.

Changes:

• Updated the example to trigger async work in an effect and forward failures via useErrorBoundary.
• Renamed UI/docs copy from “Async errors” to “Event handler and async errors” across routes/README/generated docs.
• Regenerated search and example JSON artifacts to reflect the new wording/snippet.

Reviewed changes

Copilot reviewed 5 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/routes/examples/AsyncUserCodeErrors.tsx	Refactors the example to wrap in an ErrorBoundary and forward async callback errors from useEffect.
src/routes/AsyncUserCodeErrorsRoute.tsx	Updates page title and explanatory copy to include event handler + async callback errors.
src/App.tsx	Updates nav label and warning copy to match the new wording.
lib/components/ErrorBoundary.tsx	Updates public JSDoc section header wording.
README.md	Renames the “Async errors” section and refreshes example copy/snippet.
public/generated/examples/AsyncUserCodeErrors.json	Regenerates the highlighted example HTML snippet.
public/generated/docs/ErrorBoundary.json	Regenerates docs content with updated section label.
public/generated/search-records.json	Regenerates searchable docs text with updated wording/snippet.
public/generated/search-index.json	Regenerates search index entries with updated wording/snippet.

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Project	Deployment	Actions	Updated (UTC)
react-error-boundary	Ready	Preview	May 25, 2026 1:55pm

[bvaughn]

This particular change kind of breaks the layout:

Before	After

How would you feel about this instead?

Suggested change

	Event handler and async errors
	Events and async functions

[aurorascharff]

Good catch! Looks like the layout breaks when i select it (because of the bold) even with the shorter version. So probably we should also fix the layout! Checking.

[aurorascharff]

I'll just make it slightly shorter to "events & async" to avoid changing your sidebar layout here

But I would love to freshen up the docs page app the future!

[bvaughn]

If you have ideas for the docs page, let's chat about them over on https://github.com/bvaughn/react-lib-tools 😃 That project is just an internal set of scripts and styles etc that I put together to make it easier for me to release docs for a few of my React component libs like this.

[bvaughn]

I think the change back to an effect+fetch is probably a good one here, but I wonder if we should show more than just the error path? (Currently the fetch discards the successful value so the docs example looks a bit incomplete.)

The original example had a comment placeholder:

  useEffect(() => {
    fetchGreeting(username).then(
      (response) => {
        // Set data in state and re-render ...
        response; // hidden
      },
      (error) => {
        // Show error boundary
        showBoundary(error);
      }
    );
  });

Maybe we should (re)add that?

[aurorascharff]

Agreed!

[bvaughn]

I like these changes! 👍🏼

Two small suggestions though.