Type module (ESM) incompatible with EAS build

[LinusU]

Build/Submit details page URL

https://expo.dev/accounts/loco/projects/bnm7d25/builds/0ba703f7-d5c2-4812-8ada-95874115e8a0

Summary

Build an app on EAS doesn't work if the project is setup to with "type": "module" in the package.json.

I think that this is because the EAS build checks if there is an metro.config.js, and if there isn't it creates it itself. This however won't work with "type": "module" since it will be treated as an esm file.

Locally this works for us since we have a metro.config.cjs file. But it seems like EAS build creates metro.config.js even when there is an metro.config.cjs.

Workaround: our current workaround is to include a symlink from metro.config.js to metro.config.cjs. This allows the build to go thru...

Managed or bare?

Managed

Environment

  expo-env-info 1.0.2 environment info:
    System:
      OS: macOS 13.3.1
      Shell: 5.9 - /bin/zsh
    Binaries:
      Node: 18.12.1 - ~/.nvm/versions/node/v18.12.1/bin/node
      Yarn: 1.22.19 - ~/coding/loco/order/node_modules/.bin/yarn
      npm: 8.19.2 - ~/.nvm/versions/node/v18.12.1/bin/npm
      Watchman: 2023.05.01.00 - /opt/homebrew/bin/watchman
    Managers:
      CocoaPods: 1.12.0 - /opt/homebrew/bin/pod
    SDKs:
      iOS SDK:
        Platforms: DriverKit 22.4, iOS 16.4, macOS 13.3, tvOS 16.4, watchOS 9.4
    IDEs:
      Xcode: 14.3/14E222b - /usr/bin/xcodebuild
    npmPackages:
      expo: ^48.0.0 => 48.0.17 
      react: 18.2.0 => 18.2.0 
      react-dom: 18.2.0 => 18.2.0 
      react-native: 0.71.8 => 0.71.8 
    npmGlobalPackages:
      expo-cli: 6.0.1
    Expo Workflow: managed

✔ Validating global prerequisites versions passed
✔ Checking for incompatible packages passed
✔ Checking for conflicting global packages in project passed
✔ Verifying prebuild support package versions are compatible passed
✔ Checking dependency versions for compatibility with the installed Expo SDK passed
✔ Validating Expo Config passed
✔ Checking package.json for common issues passed

Didn't find any issues with the project!

Error output

Error: @build-script-error-begin
Error loading Metro config and Expo app config: require() of ES Module /Users/expo/workingdir/build/metro.config.js from /Users/expo/workingdir/build/node_modules/metro-config/node_modules/import-fresh/index.js not supported.
metro.config.js is treated as an ES module file as it is a .js file whose nearest parent package.json contains "type": "module" which declares all .js files in that package scope as ES modules.
Instead rename metro.config.js to end in .cjs, change the requiring code to use dynamic import() which is available in all CommonJS modules, or change "type": "module" to "type": "commonjs" in /Users/expo/workingdir/build/package.json to treat all .js files as CommonJS (using .mjs for all ES modules instead).


Make sure your project is configured properly and your app.json / app.config.js is valid.
If you are using environment variables in app.config.js, verify that you have set them in your EAS Build profile configuration or secrets.
@build-script-error-end

    at /Users/expo/workingdir/build/node_modules/expo-updates/scripts/createManifest.js:52:11
Command PhaseScriptExecution failed with a nonzero exit code

Reproducible demo or steps to reproduce from a blank project

1. Create a new blank project
2. Add "type": "module" to package.json
3. Build on EAS
4. ???
5. :boo

[pencilcheck]

Is this fixed?

Btw, app.config.ts plugins is somehow loaded with commonjs so adding "type": "module" messed that up as well and app.config.cjs and app.config.mjs aren't being recognized and I can only use app.config.ts.

Is there a workaround for that as well?

----- actually nvm, I found a solution, just need to rename those plugins files into .cjs

[AizenSousuke]

Is this fixed?

Btw, app.config.ts plugins is somehow loaded with commonjs so adding "type": "module" messed that up as well and app.config.cjs and app.config.mjs aren't being recognized and I can only use app.config.ts.

Is there a workaround for that as well?

----- actually nvm, I found a solution, just need to rename those plugins files into .cjs

how is it resolved?

[billomore]

Is this fixed?

Btw, app.config.ts plugins is somehow loaded with commonjs so adding "type": "module" messed that up as well and app.config.cjs and app.config.mjs aren't being recognized and I can only use app.config.ts.

Is there a workaround for that as well?

----- actually nvm, I found a solution, just need to rename those plugins files into .cjs

I'd very much like to know too, @pencilcheck :)

[cameronmurphy]

Experiencing this too