polyfillPromise.js imports a `promise` package that never used as `hasPromise()` is always true
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Description
Description
Currently we have a runtime check for hasPromise() that leads to bundling a dead code (promise package) in the final JS bundle
hasPromise () is true by default so promise package code is never used by thousands apps in productions
Steps to reproduce
...
React Native Version
0.86.0
Affected Platforms
Runtime - Android, Runtime - iOS
Output of npx @react-native-community/cli info
System:
OS: macOS 26.5
CPU: (11) arm64 Apple M3 Pro
Memory: 5.12 GB / 36.00 GB
Shell:
version: 4.0.1
path: /opt/homebrew/bin/fish
Binaries:
Node:
version: 24.13.1
path: /usr/local/bin/node
Yarn:
version: 3.6.4
path: /opt/homebrew/bin/yarn
npm:
version: 11.8.0
path: /usr/local/bin/npm
Watchman:
version: 2025.09.01.00
path: /opt/homebrew/bin/watchman
Managers:
CocoaPods:
version: 1.16.2
path: /Users/i/.rbenv/shims/pod
SDKs:
iOS SDK:
Platforms:
- DriverKit 25.2
- iOS 26.2
- macOS 26.2
- tvOS 26.2
- visionOS 26.2
- watchOS 26.2
Android SDK:
API Levels:
- "34"
- "35"
- "36"
Build Tools:
- 33.0.1
- 34.0.0
- 35.0.0
- 36.0.0
- 37.0.0
System Images:
- android-34 | Android TV ARM 64 v8a
- android-34 | Google TV ARM 64 v8a
- android-35 | Google APIs ARM 64 v8a
- android-35 | Google Play ARM 64 v8a
- android-36 | Android TV ARM 64 v8a
- android-36 | Google TV ARM 64 v8a
Android NDK: Not Found
IDEs:
Android Studio: 2026.1 AI-261.23567.138.2611.15646644
Xcode:
version: 26.2/17C52
path: /usr/bin/xcodebuild
Languages:
Java:
version: 17.0.13
path: /usr/bin/javac
Ruby:
version: 2.6.10
path: /Users/i/.rbenv/shims/ruby
npmPackages:
"@react-native-community/cli":
installed: 20.1.0
wanted: 20.1.0
react:
installed: 19.2.3
wanted: 19.2.3
react-native:
installed: 0.86.0
wanted: 0.86.0
react-native-macos: Not Found
npmGlobalPackages:
"*react-native*": Not Found
Android:
hermesEnabled: true
newArchEnabled: true
iOS:
hermesEnabled: Not found
newArchEnabled: false
Stacktrace or Logs
...
MANDATORY Reproducer
Screenshots and Videos
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
Start in packages/react-native/Libraries/Core/polyfillPromise.js, especially lines 23-38, and trace how hasPromise() controls the promise package import. Check how that import affects the final JavaScript bundle. Done means the unused promise code is no longer bundled while Promise behavior remains intact.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- javascript
- Domain
- mobile
- Issue type
- Bug
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 68/100