fix(react/testing-library): align fireEvent with Lynx bubbling semantics by upupming · Pull Request #2532 · lynx-family/lynx-stack

upupming · 2026-04-28T10:22:56Z

Summary

TouchEvent-family events (tap, longtap, touchstart, touchmove, touchend, touchcancel, longpress) now default to bubbles: true, matching the Lynx runtime where every event whose handler signature is EventHandler<BaseTouchEvent<T>> in @lynx-js/types propagates through capture/bubble phases. Other entries (bgload, transitionend, mouse/key/focus/blur/layout, …) keep their non-bubbling default — Lynx has no symmetric capture-bind/capture-catch API for them.
Skip read-only Event.prototype accessors (bubbles, cancelable, composed) when applying EventInit via Object.assign after construction — reassigning those getters throws TypeError in strict mode. They're still applied via the EventInit dict.
Cover bind / catch / capture-bind / capture-catch handler semantics and the TouchEvent-family bubble defaults in events.test.jsx.

Test plan

pnpm vitest run src/__tests__/events.test.jsx — 41/41 pass (was previously failing in strict mode on the Object.assign(event, init) call when init carried bubbles/cancelable/composed)
CI green

Summary by CodeRabbit

Bug Fixes
- Touch-family events in the testing library now bubble by default so ancestor handlers run unless explicitly disabled; also avoids runtime errors when certain event properties are read-only.
Tests
- Added comprehensive tests validating capture vs. bubble semantics and propagation behavior for event handlers.
Documentation
- Added a changeset documenting these behavioral updates.

- TouchEvent-family events (tap, longtap, touchstart, touchmove, touchend, touchcancel, longpress) now default to bubbles: true, matching the Lynx runtime where these events propagate through capture/bubble phases. - Skip read-only Event accessors (bubbles/cancelable/composed) when applying EventInit via Object.assign — those are getters on Event.prototype and reassigning them throws TypeError in strict mode. - Add Event handler property semantics tests covering bind/catch/ capture-bind/capture-catch propagation and bubble defaults across the TouchEvent family.

changeset-bot · 2026-04-28T10:23:04Z

🦋 Changeset detected

Latest commit: 66f0503

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@lynx-js/react	Patch
@lynx-js/react-umd	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

coderabbitai · 2026-04-28T10:23:12Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Reviewing files that changed from the base of the PR and between e0b9dde and 66f0503.

📒 Files selected for processing (1)

.changeset/fix-testing-library-tap-bubbles.md

🚧 Files skipped from review as they are similar to previous changes (1)

.changeset/fix-testing-library-tap-bubbles.md

📝 Walkthrough

Walkthrough

Touch-event fireEvent helpers now default to bubbles: true; event construction omits bubbles, cancelable, and composed from init before assignment to avoid strict-mode TypeError. A patch changeset and tests validating handler-phase and propagation behavior were added.

Changes

Cohort / File(s)	Summary
Changeset / Docs `\.changeset/fix-testing-library-tap-bubbles.md`	Adds a patch-level changeset documenting TouchEvent bubbling default and the change to event property assignment.
Tests `packages/react/testing-library/src/__tests__/events.test.jsx`	Adds tests covering Lynx handler phase semantics (`bind`, `catch`, `capture-bind`, `capture-catch`), propagation behavior, and verifies Touch-event bubbling defaults.
Implementation `packages/react/testing-library/src/fire-event.ts`	Sets TouchEvent-family entries to default `bubbles: true`; changes event creation to exclude `bubbles`, `cancelable`, `composed` from direct assignment to prevent TypeError in strict mode.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Suggested reviewers

HuJean
Yradex
hzy

Poem

🐇 I tapped the world and let it go,
Bubbles rising from tip to toe.
I avoided proto's grumpy bite,
Now events travel left and right—
A tiny hop, a merry light.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: aligning fireEvent TouchEvent behavior with Lynx bubbling semantics through updates to event defaults and implementation.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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Commit unit tests in branch fix/testing-library-tap-bubbles

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codecov · 2026-04-28T10:25:34Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

📢 Thoughts on this report? Let us know!

coderabbitai

🧹 Nitpick comments (1)

packages/react/testing-library/src/__tests__/events.test.jsx (1)

314-330: Add longtap to the default-bubbling ancestor test matrix.

Line 314 currently validates touchstart/touchmove/touchend/touchcancel/longpress, but longtap also changed to default bubbles: true in fire-event.ts. Including it here would close that regression gap.

🧪 Proposed test update

-  it.each(['touchstart', 'touchmove', 'touchend', 'touchcancel', 'longpress'])(
+  it.each(['longtap', 'touchstart', 'touchmove', 'touchend', 'touchcancel', 'longpress'])(
     '%s: bubbles to ancestor handlers by default',
     (eventName) => {
       const parent = vi.fn();
       const childRef = createRef();

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@packages/react/testing-library/src/__tests__/events.test.jsx` around lines
314 - 330, Update the test matrix in the it.each call so the ancestor-bubbling
test covers the 'longtap' event as well: inside the array passed to it.each
(currently ['touchstart','touchmove','touchend','touchcancel','longpress']), add
'longtap' so that the loop invokes fireEvent[eventName](childRef.current) for
'longtap' and asserts parent handler was called; this ensures the change in
fire-event.ts (default bubbles: true for longtap) is covered by the test.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@packages/react/testing-library/src/__tests__/events.test.jsx`:
- Around line 314-330: Update the test matrix in the it.each call so the
ancestor-bubbling test covers the 'longtap' event as well: inside the array
passed to it.each (currently
['touchstart','touchmove','touchend','touchcancel','longpress']), add 'longtap'
so that the loop invokes fireEvent[eventName](childRef.current) for 'longtap'
and asserts parent handler was called; this ensures the change in fire-event.ts
(default bubbles: true for longtap) is covered by the test.

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📥 Commits

Reviewing files that changed from the base of the PR and between e15852f and 5217110.

📒 Files selected for processing (3)

.changeset/fix-testing-library-tap-bubbles.md
packages/react/testing-library/src/__tests__/events.test.jsx
packages/react/testing-library/src/fire-event.ts

codspeed-hq · 2026-04-28T11:32:48Z

Merging this PR will not alter performance

✅ 81 untouched benchmarks
⏩ 26 skipped benchmarks¹

_{Comparing fix/testing-library-tap-bubbles (66f0503) with main (e15852f)}

26 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

relativeci · 2026-04-28T11:33:50Z

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relativeci · 2026-04-28T11:33:52Z

React Example

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relativeci · 2026-04-28T11:33:52Z

React External

#799 Bundle Size — 680.27KiB (0%).

66f0503(current) vs 3920afa main#798(baseline)

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upupming requested review from HuJean, Yradex and hzy as code owners April 28, 2026 10:22

coderabbitai Bot added the framework:React label Apr 28, 2026

coderabbitai Bot reviewed Apr 28, 2026

View reviewed changes

upupming added 2 commits April 28, 2026 19:13

chore: shorten testing-library changeset

e0b9dde

chore: changeset under @lynx-js/react

66f0503

Yradex approved these changes Apr 28, 2026

View reviewed changes

upupming merged commit e4ace87 into main Apr 28, 2026
106 of 111 checks passed

upupming deleted the fix/testing-library-tap-bubbles branch April 28, 2026 12:39

github-actions Bot mentioned this pull request Apr 28, 2026

chore: Release 2026-05-04 00:55:51 #2535

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fix(react/testing-library): align fireEvent with Lynx bubbling semantics#2532

fix(react/testing-library): align fireEvent with Lynx bubbling semantics#2532
upupming merged 3 commits intomainfrom
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