Expo Client for iOS is not working

I’m with an issue happening only on my Expo Client for iOS, can someone support me? I think that is something related to the Babel Runtime on the Expo Client, once I am able to publish my app, but I am not able to execute on the Expo Client.

I’m getting this error ONLY on Expo Client.


Hey @obetomuniz,

Can you check your .babelrc file and your dependencies to make sure everything is copacetic? Also, googling that issue yielded a lot of results that may help you out!



I’m not sure about that. Looks like some problem in the Expo Client Runtime. I mean, on the Expo Client running on the iOS Simulator everything works well. Only when I publish my app and try to download the app to my Expo Client on my physical phone this problem appear. I already tried change the presets on .babelrc or something like that, but the build on the Expo Client running on my iPhones not is working. I already tried in 3 iPhone (5s, 7 Plus and X), but I catch that same error.

Sadly, this error is not easy to debug also, once it is not describing the module or the line with the problem. It’s another negative point for the Expo ecosystem. I’m creating a big product with Expo, but after this problem and the bad support, I am really planning to remove Expo


I already solved my problem. It was happening because of some weird support of babel with async/await feature that only Expo Client was figuring.

I added the babel-plugin-transform-async-to-generator on the project and everything works well.

Hope to not figure issues like that again. The error debugger on Expo Client is very bad.

@obetomuniz I’ve been having this exact same issue, but I’ve tried installing the babel-plugin-transform-async-to-generator and a few other “fixes” in this thread - https://github.com/facebook/react-native/issues/4844

My package.json is - https://gist.github.com/jm90m/c0a5938ab963d57dd1825a67890f5c7c

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