Why does my Expo app run in Expo Go but not as a development build?

Question

I've created a development build of an Expo app using EAS. Previously I would open the app in Expo Go by running npx expo start and scanning the Metro Bundler QR code.

Now, when I try to do the same thing, Expo Go asks whether I want to open the project in Expo Go or as a "Development Build". It works fine in Expo Go, but crashes immediately when I attempt to open the dev build. The error reads:

null is not an object (evaluating '_ReanimatedModule.default.createNode')

This error is suspiciously similar to one that I encountered earlier in development, which I resolved by downgrading to React Native version 0.69.6. I'm also encountering a second error that says "'main' has not been registered", but I suspect this is downstream of the first error.

I have the same issue when I try to run the app with npx expo start --dev-client.

Any ideas why I might be having this problem?

Holbrook

Same problem here. No solutions so far. – Minster

Answer 1

It sounds like you may have run expo prebuild (https://docs.expo.dev/workflow/prebuild/) which removes "main": "node_modules/expo/AppEntry.js", from app.json. Try to create a new expo app and look at it's app.json file.

When you run expo prebuild it changes a few things with your project (see "side effects" in the prebuild docs).

I'm actually working through some issues with that right now too. I thought I had to run prebuild but turns out I didn't have to. Ever since I ran it my app will not load via the dev-client way. I can however switch back to npx expo start (NOT npx expo start --dev-client, see the scripts section of app.json as that is also changed when prebuild is run).

Let me know if you are able to get your app to load after re-adding the main stuff to app.json.

Ps, are you by chance using react-native-google-mobile-ads?

Paramecium

That worked for me, except that I put the main inside package.json, not app.json! – Schmeltzer

How would this work with expo-router/entry file based routing system? – Skiascope

I'm using react-native-google-mobile-ads, facing the same issue, any tips? – Substitution

@PauloLima Make sure you have a valid ios_app_id and android_app_id in app.json. "react-native-google-mobile-ads": { "android_app_id": "ca-app-pub-********~********", "ios_app_id": "ca-app-pub-********~********" } – Paramecium

In case anyone stumbles on the same question as @conor909, set the following in your package.json: "main": "expo-router/entry". That worked for me. – Exam

based on my observations, for expo@^50 it doesn't change entry etc., but only looks if expo-dev-client is present as an installed dependency. That is, if it is, expo start will target native dev builds, not Expo Go; which I wanted to temporarily avoid to test on iOS simulator with Expo Go, so I just removed expo-dev-client dependency and it worked. – Interdiction

@PauloLima Have you managed to find a solution? I have the same issue – Brann

Answer 2

Not sure if this is relevant anymore, but for me what worked was uninstalling expo-dev-client package.

Layette

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Answer 3

I had the same issue, I simply rebuild using EAS with this command

eas build --platform android --profile development

you can follow these steps

Morten