onTextLayout incorrectly returns multiple lines for text that renders in a single line
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Description
Description
onTextLayout is returning incorrect lines data for simple single-line text.
In previous React Native versions (tested on Expo 52 with react-native 0.79), the lines array matched the actual number of rendered lines. After the latest update (RN 0.81), some texts that clearly render in one line are reported as two lines.
This breaks logic that depends on overflow detection (e.g., switching between normal text and marquee scrolling). Because onTextLayout now gives false positives, it’s impossible to reliably detect when text exceeds one line.
Steps to reproduce
The bug is present in Expo template when created with npx create-expo-app@latest.
- Install the dependencies
npm install - Open the app in Expo Go application
- See the log in terminal. You should see the text is rendered in one line, but
onTextLayoutgives an array with 2 items.
React Native Version
0.81.5
Affected Platforms
Runtime - Android
Output of npx @react-native-community/cli info
System:
OS: macOS 26.1
CPU: (11) arm64 Apple M3 Pro
Memory: 286.83 MB / 18.00 GB
Shell:
version: 3.2.57
path: /bin/sh
Binaries:
Node:
version: 22.12.0
path: /Users/smhd/.nvm/versions/node/v22.12.0/bin/node
Yarn: Not Found
npm:
version: 10.9.0
path: /Users/smhd/.nvm/versions/node/v22.12.0/bin/npm
Watchman:
version: 2024.12.02.00
path: /opt/homebrew/bin/watchman
Managers:
CocoaPods: Not Found
SDKs:
iOS SDK:
Platforms:
- DriverKit 24.2
- iOS 18.2
- macOS 15.2
- tvOS 18.2
- visionOS 2.2
- watchOS 11.2
Android SDK: Not Found
IDEs:
Android Studio: 2025.1 AI-251.26094.121.2513.14007798
Xcode:
version: 16.2/16C5032a
path: /usr/bin/xcodebuild
Languages:
Java:
version: 17.0.14
path: /usr/bin/javac
Ruby:
version: 2.6.10
path: /usr/bin/ruby
npmPackages:
"@react-native-community/cli": Not Found
react:
installed: 19.1.0
wanted: 19.1.0
react-native:
installed: 0.81.5
wanted: 0.81.5
react-native-macos: Not Found
npmGlobalPackages:
"*react-native*": Not Found
Android:
hermesEnabled: Not found
newArchEnabled: Not found
iOS:
hermesEnabled: Not found
newArchEnabled: Not found
info React Native v0.82.1 is now available (your project is running on v0.81.5).
info Changelog: https://github.com/facebook/react-native/releases/tag/v0.82.1
info Diff: https://react-native-community.github.io/upgrade-helper/?from=0.81.5&to=0.82.1
info For more info, check out "https://reactnative.dev/docs/upgrading?os=macos".
Stacktrace or Logs
No stacktrace available. Not related in this case.
MANDATORY Reproducer
https://github.com/SMhdAsadi/onTextLayout-issue-rn81
Screenshots and Videos
This is the first page of a new Expo project in default template:
The title "Welcome!" is rendered in one line, but is reported to be in two lines in onTextLayout prop.
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
Run the mandatory reproducer at https://github.com/SMhdAsadi/onTextLayout-issue-rn81 with the Expo template on Android and inspect the onTextLayout output for the single-line “Welcome!” text. Trace the React Native Android text-layout path that produces the lines array. Done means a text that renders on one line reports one line without breaking overflow detection.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- android, react-native
- Domain
- mobile-dev
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 55/100