fix(web): repair web regressions when using expo web support#8924
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fix(web): repair web regressions when using expo web support#8924
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using the web-targeted firebase-js-sdk implies that we need functioning implementations of Headers, Request, Response, fetch, and Readable Stream react-native does not provide those so we polyfill for them whenever we are using firebase-js-sdk in a native environment and need them however, Expo can actually use react-native-firebase in a pure web context, where those things are functioning and need no polyfill - in fact our polyfills rely on react-native internals and are harmful as they create errors during web bundling Expo web uses the metro bundler which allows platform-specific resolution though, so if we add a no-op polyfills.web file, it is resolved instead of the problematic polyfills, and everything works
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Shervanator
approved these changes
Mar 10, 2026
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Description
Expo can run react-native-firebase successfully in web mode (
npx expo start --web), or at least it used to be able to for most packages.But there are (or were) two problems:
1- The remote-config package and the AI package have problematic polyfills that touch react-native internals though (specifically, react-native-fetch-api uses an internal react-native Blob import which goes to a native react-native method, and that won't work on web)
2- The auth package uses a method from firebase-js-sdk that is only exposed on the react-native bundle exported for react-native only from firebase-js-sdk package.json
For item 1, I made web specific polyfills that were empty. Metro loads the
.websuffix files for the web platform first, so it stubs out the problematic polyfills, while they are still loaded for the native platforms (which includes "other" - where the firebase-js-sdk is running in the react-native environment vs the browser environment)For item 2, I just check if we are
Platform.OS === "web"prior to attempting the react-native-specific method call during auth initialization, and that fixes things.Related issues
@react-native-firebase/remote-configweb fallback imports RN private modules and crashes Expo web (__fbBatchedBridgeConfig) #8903Release Summary
Two fix commits, should generate a semver patch release
Checklist
AndroidiOSOther(macOS, web)e2etests added or updated inpackages/\*\*/e2ejesttests added or updated inpackages/\*\*/__tests__Test Plan
Extensive use of https://github.com/mikehardy/rnfbdemo/blob/main/make-expo-demo.sh - which I augmented to include a web test for this purpose, and ran against local packages made using
.github/workflows/scripts/create_npm_packages.sh packages ~/packagesThink
react-native-firebaseis great? Please consider supporting the project with any of the below:React Native FirebaseandInvertaseon Twitter