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fix: app crashing due to undefined settings constant accessor #923

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fix: app crashing due to undefined settings constant accessor #923

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0daae68
fix: app crashing due to undefined settings constant accessor
CalhamJNorthway Sep 10, 2025
d9f43a5
Merge branch 'main' into fix/rn-fabric-settings-undefined-crash
joker23 Nov 21, 2025
f8eca98
chore: addressing PR comments
joker23 Nov 21, 2025
655ac7a
Merge branch 'main' into fix/rn-fabric-settings-undefined-crash
joker23 Nov 25, 2025
10b9ccc
Merge branch 'main' into fix/rn-fabric-settings-undefined-crash
joker23 Dec 5, 2025
3d8605d
Merge branch 'main' into fix/rn-fabric-settings-undefined-crash
joker23 Dec 8, 2025
0ee1355
Merge branch 'main' into fix/rn-fabric-settings-undefined-crash
joker23 Jan 29, 2026
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1 change: 1 addition & 0 deletions packages/sdk/react-native/package.json
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,7 @@
"tsw": "yarn tsc --watch",
"start": "rimraf dist && yarn tsw",
"lint": "eslint . --ext .ts,.tsx",
"lint:fix": "eslint . --ext .ts,.tsx --fix",
"prettier": "prettier --write '**/*.@(js|ts|tsx|json|css)' --ignore-path ../../../.prettierignore",
"test": "jest",
"coverage": "yarn test --coverage",
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20 changes: 13 additions & 7 deletions packages/sdk/react-native/src/platform/locale.ts
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Original file line number Diff line number Diff line change
@@ -1,12 +1,18 @@
import { NativeModules, Platform } from 'react-native';

/**
* Ripped from:
* https://dev.to/medaimane/localization-and-internationalization-in-react-native-reaching-global-audiences-3acj
* Apps opted into Fabric (the new architecture of React Native)
* may not have access to the SettingsManager.settings.AppleLocale property.
* It is now common to use the `getConstants` method to access these constant properties with Fabric enabled apps.
*/
const locale =
Platform.OS === 'ios'
? NativeModules.SettingsManager?.settings?.AppleLocale // iOS
: NativeModules.I18nManager?.localeIdentifier;
const localeIdentifier = Platform.select({
ios: () => {
const settings =
NativeModules.SettingsManager?.settings ??
NativeModules.SettingsManager?.getConstants()?.settings;
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@cursor cursor bot Dec 8, 2025

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Bug: Incorrect accessor path for getConstants() in Fabric

The fallback accessor NativeModules.SettingsManager?.getConstants()?.settings likely has an incorrect property path. In React Native's new Fabric architecture, getConstants() typically returns constants directly at the top level (e.g., {AppleLocale: 'en_US'}), not nested under a settings property. This means getConstants()?.settings would return undefined, causing AppleLocale to never be found even when available through getConstants(). The accessor likely needs to be getConstants()?.AppleLocale or getConstants() should replace the entire settings variable.

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@cursor cursor bot Jan 29, 2026

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Missing optional chaining on getConstants function call

High Severity

The code NativeModules.SettingsManager?.getConstants()?.settings will throw a TypeError if SettingsManager exists but getConstants is not a function. The optional chain before getConstants() only guards against SettingsManager being nullish, not getConstants being undefined. In older React Native versions without Fabric/TurboModules, getConstants may not exist on SettingsManager. The fix is to use getConstants?.() to safely handle the case where the method doesn't exist.

Fix in Cursor Fix in Web

return settings?.AppleLocale;
},
default: () => NativeModules.I18nManager?.localeIdentifier,
});

export default locale;
export default localeIdentifier();