[Bug Fix][Fabric] Fix onChangeText firing twice when first typing in TextInput #14788
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HariniMalothu17
changed the title
| onChangeArgs.eventCount = ++m_nativeEventCount; | ||
| emitter->onChange(onChangeArgs); | ||
| auto currentText = GetTextFromRichEdit(); | ||
| if (currentText != m_lastOnChangeText) { |
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This seems like a pretty expensive check. If there was a very large set of text in the textiput, this comparison would get relatively expensive. Is there not some code flow way of determining that the event is not needed?
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/azp run |
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Pull Request Overview
This PR fixes duplicate onChangeText events in Fabric TextInput by only emitting the change when the underlying text really changed.
- Added a check for the RichEdit
EM_GETMODIFYflag before firingonChange - Clear the modify flag (
EM_SETMODIFY) after handling to prevent redundant events - Updated prerelease metadata in the JSON manifest
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| vnext/Microsoft.ReactNative/Fabric/Composition/TextInput/WindowsTextInputComponentView.cpp | Wrap onChange emission in a modify-flag check |
| change/react-native-windows-5060f8b9-f264-472c-a212-48147bd0b243.json | Added prerelease entry with bugfix comment |
Comments suppressed due to low confidence (3)
vnext/Microsoft.ReactNative/Fabric/Composition/TextInput/WindowsTextInputComponentView.cpp:1290
- [nitpick] Consider renaming the variable
modifiedtoisModified(or similar) to indicate that it holds a boolean-like flag.
LRESULT modified = 0;
vnext/Microsoft.ReactNative/Fabric/Composition/TextInput/WindowsTextInputComponentView.cpp:1291
- Consider adding a unit test that simulates typing and ensures
onChangefires exactly once per actual text change, covering this new deduplication logic.
m_textServices->TxSendMessage(EM_GETMODIFY, 0, 0, &modified);
vnext/Microsoft.ReactNative/Fabric/Composition/TextInput/WindowsTextInputComponentView.cpp:1295
- [nitpick] Indent the
onChangeArgslines and theemitter->onChangecall to clearly show they are inside theif (modified)block for better readability.
facebook::react::WindowsTextInputEventEmitter::OnChange onChangeArgs;
| @@ -0,0 +1,7 @@ | |||
| { | |||
| "type": "prerelease", | |||
| "comment": "Fixed OnchangeText bug", | |||
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Update the comment to match the code casing, e.g., "Fixed onChangeText bug", for consistency.
| "comment": "Fixed OnchangeText bug", | |
| "comment": "Fixed onChangeText bug", |
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Description
Type of Change
Why
In Fabric TextInput, when a user types a single character, the onChangeText callback was being triggered twice instead of once. This was inconsistent with Paper TextInput behavior and could cause issues in applications that rely on accurate change event counts.
Resolves [https://github.com//issues/12780 ]
What
The new solution uses text-based deduplication - it only emits onChange when the current text differs from the last text for which onChange was emitted. This prevents duplicate onChange events while preserving all expected onChange behavior.
Screenshots
(
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Testing
E2E test ran succesfully
Changelog
yes
Add a brief summary of the change to use in the release notes for the next release.
Microsoft Reviewers: Open in CodeFlow