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useNativeVariable("--x") fails to type-check in a React Native app: the package types it () => never #543
Description
Before submitting a new issue
- I tested using the latest version of the library, as the bug might be already fixed.
- I tested using a supported version of react native.
- I checked for possible duplicate issues, with possible answers.
Bug summary
useNativeVariable and useUnstableNativeVariable read a CSS variable's resolved value on native, and the declaration a React Native app is checked against takes no argument: the package's types entry re-exports ./runtime, which re-exports ./web, whose stub is declared () => never (dist/typescript/module/src/web/api.d.ts). TypeScript does not follow the .native suffix a bundler does, so it never reaches runtime.native.d.ts, whose declaration is useNativeVariable(name: string): any.
Library version
main at 2421ea7 (0.0.0-nightly.2421ea7)
Environment info
System:
OS: Windows 11 10.0.26300
CPU: "(32) x64 AMD Ryzen 9 9950X3D 16-Core Processor "
Memory: 161.91 GB / 255.67 GB
Binaries:
Node:
version: 26.12.1
path: C:\Program Files\nodejs\node.EXE
Yarn: Not Found
npm:
version: 12.2.1
path: C:\Program Files\nodejs\npm.CMD
Watchman: Not Found
SDKs:
Android SDK:
API Levels:
- "33"
- "35"
- "35"
- "35"
- "36"
- "37"
Build Tools:
- 35.0.0
- 36.0.0
- 36.1.0
- 37.0.0
System Images:
- android-26 | Google APIs Intel x86_64 Atom
- android-28 | Google APIs Intel x86_64 Atom
- android-29 | Google APIs Intel x86_64 Atom
- android-30 | Google APIs Intel x86_64 Atom
- android-31 | Google APIs Intel x86_64 Atom
- android-32 | Google APIs Intel x86_64 Atom
- android-33 | Google APIs Intel x86_64 Atom
- android-34 | Google APIs Intel x86_64 Atom
- android-35 | Google APIs Intel x86_64 Atom
- android-36.1 | Google Play Intel x86_64 Atom
- android-36.1 | Pre-Release 16 KB Page Size Google Play Intel x86_64 Atom
- android-37.0 | Google APIs Intel x86_64 Atom
Android NDK: Not Found
Windows SDK: Not Found
IDEs:
Android Studio: AI-262.9437.185.2621.16467767
Visual Studio: Not Found
Languages:
Java:
version: 17.0.20.1
path: C:\Program Files\Microsoft\jdk-17.0.20.101-hotspot\bin\javac.EXE
Ruby: Not Found
npmPackages:
"@react-native-community/cli": Not Found
react:
installed: 19.3.1
wanted: 19.3.1
react-native:
installed: 0.88.1
wanted: 0.88.1
react-native-windows: Not Found
npmGlobalPackages:
"*react-native*": Not Found
Android:
hermesEnabled: Not found
newArchEnabled: Not found
iOS:
hermesEnabled: Not found
newArchEnabled: Not foundSteps to reproduce
- Clone the reproducer, a React Native app's three files on the nightly build of
main, and install:git clone https://github.com/YevheniiKotyrlo/react-native-css-native-variable-types cd react-native-css-native-variable-types npm install - Run
npx tsc.
index.ts:
import { useNativeVariable, useUnstableNativeVariable } from "react-native-css";
export function useFontSans(): string {
const fromStable = useNativeVariable("--font-sans");
const fromUnstable = useUnstableNativeVariable("--font-sans");
return String(fromStable ?? fromUnstable);
}package.json:
{
"name": "react-native-css-native-variable-types",
"private": true,
"type": "module",
"dependencies": {
"react": "19.3.1",
"react-native": "0.88.1",
"react-native-css": "0.0.0-nightly.2421ea7"
},
"devDependencies": {
"@types/react": "19.3.0",
"typescript": "7.0.2"
}
}tsconfig.json:
{
"compilerOptions": {
"strict": true,
"skipLibCheck": true,
"module": "preserve",
"jsx": "react-jsx",
"target": "es2022",
"noEmit": true
},
"files": ["index.ts"]
}Expected: both calls type-check, and the value is typed, string | undefined or what resolveValue can answer, rather than any.
Actual: both calls fail with TS2554, because the declaration TypeScript reads takes no argument. npx tsc in the reproducer at 9f2f65d, Windows 11, Node 26.12.1, TypeScript 7.0.2, React Native 0.88.1:
index.ts(4,40): error TS2554: Expected 0 arguments, but got 1.
index.ts(5,50): error TS2554: Expected 0 arguments, but got 1.
Reproducible example repository
https://github.com/YevheniiKotyrlo/react-native-css-native-variable-types
Activity