feat(expo): add first-class Re.Pack integration by whydidoo · Pull Request #1425 · callstack/repack

whydidoo · 2026-07-30T10:24:23Z

Summary

This PR introduces first-class Expo support for Re.Pack through a new @callstack/repack-expo package.

It allows Expo SDK 56 applications using prebuild/CNG to use Rspack and the existing Re.Pack runtime, including ScriptManager and Module Federation v2, without changing the core Re.Pack packages.

The package remains private while we validate the initial integration contract.

What’s included

An Expo Config Plugin that configures generated iOS and Android projects for Re.Pack.
An ExpoPlugin for Rspack that owns the required Expo/Re.Pack defaults:
- Expo Router and plain entry resolution
- Babel configuration
- React Native and monorepo module resolution
- images, density variants, fonts and XML assets
- EXPO_PUBLIC_* environment variables
- source maps and symbolication
- packaged local chunks through ScriptManager
CLI commands for initial setup and diagnostics:
- npx @callstack/repack-expo init
- npx @callstack/repack-expo doctor
Development, native Release and EAS Build integration.
Expo Router support without importing Metro runtime behavior.
Module Federation v2 support using the existing public Re.Pack plugin and ScriptManager.
Expo host and Expo widget validation applications for iOS and Android.

Module Federation v2

Module Federation remains explicit and application-owned, matching regular Re.Pack behavior.

The implementation supports:

Expo host → Expo widget
Expo host → regular Re.Pack MF v2 widget
packaged local React.lazy() chunks alongside remote widgets
remotely deployed widget chunks, assets and fonts
platform-specific iOS and Android manifests
the existing ScriptManager resolver, storage and security mechanisms

Remote widgets cannot provide native dependencies. Native modules must already be installed and linked in the host application.

Native integration

@callstack/repack-expo init only updates application-owned configuration.

Native changes are applied through the Expo Config Plugin during expo prebuild. The integration does not require users to maintain custom Swift, Kotlin, Gradle or Xcode changes manually.

Development applications are launched with:

npm run repack:start
npm run repack:ios
# or
npm run repack:android

changeset-bot · 2026-07-30T10:24:26Z

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vercel · 2026-07-30T10:24:30Z

@whydidoo is attempting to deploy a commit to the Callstack Team on Vercel.

A member of the Team first needs to authorize it.

dannyhw · 2026-07-30T13:41:11Z

@whydidoo can you check the merge conflicts?

dannyhw · 2026-07-30T14:01:52Z

+    "expo-router": "~56.2.7",
+    "expo-status-bar": "~56.0.4",
+    "react": "19.2.3",
+    "react-native": "0.85.3",


I recently updated our react native version to "0.86.0"
also note that we have some of our package versions in catalogs in pnpm workspace
would be good to keep react native versions in sync across projects I think

Expo SDK 57 currently expects React Native 0.86.2 and React 19.2.3.
I’ve kept both Expo examples on the same Expo-compatible versions rather than forcing the default catalog versions. We could add a dedicated Expo SDK 57 catalog later to keep those versions centralized as well.

dannyhw · 2026-08-03T13:31:35Z

lets try and align the Expo package and examples with the workspace catalogs

At the moment the new Expo projects use direct pins for React, React Native, Community CLI packages, the React Native Babel preset, React types, TypeScript, and Module Federation, while existing testers use the shared catalog entries. In particular, the Expo apps use React Native 0.86.2 while the catalog is 0.86.0; if 0.86.2 is the Expo 57-compatible version, please update the shared React Native catalog to 0.86.2 and have the relevant examples consume it through the catalog.

The Expo SDK packages themselves can live in a dedicated Expo 57 catalog, shared by both Expo fixtures, so their versions do not drift. The same applies to any Expo-specific React, CLI, or Babel compatibility pins that genuinely cannot use the default catalog.

regarding typescript version I have a separate pr that updates typescript to v7 which we could merge before this and then update those expo projects to be on v7 as well

bartekkrok · 2026-08-05T09:09:49Z

+}
+
+export function configureExpoRouterEntry(
+  rules: unknown[],


Suggested change

rules: unknown[],

rules: RuleSetRule[],

bartekkrok · 2026-08-05T09:15:28Z

+      resolvedEntry.projectRoot
+    );
+    const caller = createExpoBabelCaller({
+      isDev: compiler.options.mode === 'development',


Suggested change

isDev: compiler.options.mode === 'development',

isDev: compiler.options.mode !== 'production',

Since export type Mode = "development" | "production" | "none"; when someone will set none then will take production behaviour. Not sure if it's in purpose

bartekkrok · 2026-08-05T10:06:31Z

+
+const ANDROID_MAIN_MODULE_TAG = 'repack-expo-android-main-module';
+const ANDROID_BUNDLE_COMMAND_TAG = 'repack-expo-android-bundle-command';
+const EXPO_CLI_BLOCK = `    // Use Expo CLI to bundle the app, this ensures the Metro config


I think that instead of matching the entire block character-by-character we could use RegExp with tolerance for whitespace. Both here (EXPO_CLI_BLOCK) and in ios.ts (EXPO_CLI_DEFAULTS)

bartekkrok · 2026-08-05T10:27:57Z

+    if (
+      parent === current ||
+      fs.existsSync(path.join(current, '.git')) ||
+      fs.existsSync(path.join(current, 'pnpm-workspace.yaml'))


Suggested change

fs.existsSync(path.join(current, 'pnpm-workspace.yaml'))

fs.existsSync(path.join(current, 'pnpm-workspace.yaml')) ||

(currentPackageJson && 'workspaces' in currentPackageJson)

feat(expo): add first-class Re.Pack integration

b57cbb3

whydidoo requested a review from dannyhw July 30, 2026 10:24

whydidoo added the area:3rd-party The issue is about 3rd party package or library. label Jul 30, 2026

This was linked to issues Jul 30, 2026

[TRACKING] Enhanced Expo support #1413

Open

Re.pack and its Module Federation / Micro-frontends is not working with expo #1396

Open

dannyhw reviewed Jul 30, 2026

View reviewed changes

whydidoo added 4 commits July 30, 2026 19:25

feat(expo): support SDK 56 and newer

98ca23d

Merge branch 'main' into feat/expo-repack-support

e2c2c3c

fix(expo): declare worklets Babel dependencies

922aca7

fix(expo): configure tester remote assets

f0d1727

bartekkrok reviewed Aug 5, 2026

View reviewed changes

Merge branch 'main' into feat/expo-repack-support

70db013

bartekkrok reviewed Aug 5, 2026

View reviewed changes

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feat(expo): add first-class Re.Pack integration - #1425

feat(expo): add first-class Re.Pack integration#1425
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	isDev: compiler.options.mode === 'development',
	isDev: compiler.options.mode !== 'production',

	fs.existsSync(path.join(current, 'pnpm-workspace.yaml'))
	fs.existsSync(path.join(current, 'pnpm-workspace.yaml')) \|\|
	(currentPackageJson && 'workspaces' in currentPackageJson)

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whydidoo commented Jul 30, 2026

Summary

What’s included

Module Federation v2

Native integration

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