I have a React Native app which was running perfectly earlier this morning. I've deleted package-lock.json after mistakenly doing an npm install instead of a yarn install. Then I've ran yarn install and now when I try to run my app I get this error at the packager:
error: bundling failed: index.js: "" is not a valid identifer name
BUNDLE [ios, dev] ./index.js ░░░░░░░░░░░░░░░░ 0.0% (0/1), failed.
I've also closed packager and Vscode, removed node_modules and tried running yarn install again but I get the same error. I haven't changed a single line in my code and it was working before that.
What is going on?
It is already opened as an issue.
https://github.com/facebook/react-native/issues/27118
https://github.com/facebook/react-native/issues/27120#issuecomment-549832676
Simply you need to delete "node_modules" and again run the command:
npm i or yarn
Also, you can simply re-create the scratch project with
react-native init example
It will work as expected. They reverted the changes on #babel/run-time at 7.7.1 version.
Have fun 🎊🎉
Delete node_modules and packages-lock.json, erase trash, close Metro Bundle, delete the app from emulator/simulator and run npm install, this way worked for me.
I had the same issue and none of the solutions mentioned here or in the links worked for me. The issue was the react-native local and global versions were different.
node node_modules/react-native/local-cli/cli.js run-ios worked for me.
and while bundling, node node_modules/react-native/local-cli/cli.js bundle --entry-file...
In short replace react-native with node node_modules/react-native/local-cli/cli.js when trying to run or bundle
I have just created new React Native App and when I try to run it on iOS it's ruining without any problem but when I run it on android it is showing me an Error says
undefined is not a function (evaluating 'Object.getOwnPropertyDescriptors(arguments[i])') (http://10.0.2.2:8081/index.delta?platform=android&dev=true&minify=false:3573)
This error shown in the (Red screen) React Native Error Screen after the app has been installed on the device.
its worked for me install this dependency
npm i object.getownpropertydescriptors
link
Unbelievable solution but worked for me 🎯
I guessed that the problem was some kind of dependency upgrade, and because React Native does not come locked to working versions, something got published and broke it.
I grabbed a yarn.lock from a project from over the weekend, pasted that into my project's yarn.lock file and then did yarn at the command line to have it automatically prune/lock things back up. Somewhere in that mess, it grabbed the right stuff and now I can use Android again. Not a great fix, but hopefully it helps!
Copy this yarn.lock contents
Past it over your project's yarn.lock contents
run yarn in the CLI
Note: I got this solution from here.
temporary Fix:
Add the following to your package.json:
"resolutions": {
"#babel/helpers": "7.2.0",
"#babel/runtime": "7.2.0"
}
Then run rm -rf node_modules && yarn && yarn start --reset-cache
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Getting the following message when I init a new project and then launch the Xcode emulator:
React-Native Version Mismatch
Javascript Version 0.50.1
Native version: 0.50.0
Make sure you have rebuilt the native code. ...
Does anyone know what is going on here and can help me?
This is what I've done with it:
Close all terminals and run build again.
You may forget to close nodejs terminal from another project, and they happen to have installed different react version.
So the code fetches from nodejs server conflicts with the native one.
In case you created your react-native app using create-react-native-app. You should have a app.json (expo). and a package.json file, check if the expo versions match and change accordingly. For example in my case the problem was that in the app.json file I had a 25.0.0 version for the expo sdkVersion attribute, I change that to 23.0.0 and everything worked.
package.json:
"dependencies": {
"expo": "^23.0.4",
"react": "16.0.0",
"react-native": "^0.50.4"
}
app.json:
{
"expo": {
"sdkVersion": "23.0.0" // before was 25.0.0
}
}
Just go to your android/app/build.gradle and then add to the dependencies section:
dependencies{
compile ("com.facebook.react:react-native:0.50.3") { force = true }
}
/// the react native version can be found in package.json
For Android developers who couldn't get it fixed by just closing and rebuilding, Manually uninstall the app on the emulator/device.
just force react native version in your android's app level gradle file, in the dependencies section.
compile ("com.facebook.react:react-native:0.52.0") { force = true }
worked for me
If you're running your React Native app through Expo, upgrading React Native is liable to cause this error (as noted at https://github.com/expo/expo/issues/923).
If that's your scenario, your options are:
Bump Expo (which is listed in your package.json) to a version that is compatible with your React Native version (if one exists, which may not be the case - judging by the linked issue, I figure that Expo support trails React Native releases).
Discard your changes, delete and reinstall your Node modules, Eject from Expo, and then (after checking that you can still run your app post-ejection) try your upgrade again.
I've never seen this error before, but whenever I can't get Xcode and React-Native to play well together, I do a couple of things. Check what version of Xcode I'm working with. If it needs to be updated, I update it. Then clearing watchman and the cache are the second place I go. I don't use the reset cache command. It always says that I need to verify the cache, so I skip that (you can do it though, I just get confused). I use rm -rf $TMPDIR/react-* to get rid of any cached builds. If that doesn't work, I try to build the app in Xcode, then work my way from there, to build it with react-native run-ios. With this error message, it seems you might start by trying to build it with Xcode. Hope that helps...let me know your progress with it. Good luck! (Also, you could update to RN 0.51 as another attempt to get your versions synced.)
I had this problem for the longest time and none of the above solutions helped. I was in the middle of upgrading react native in a create-react-native-app project until I found out that not all versions of Expo support the latest React Native.
Found this page linked in the documentation that shows which version combinations of React Native, React, and Expo are officially supported:
Source: https://github.com/react-community/create-react-native-app/blob/master/VERSIONS.md
Editing the app.json and package.json files to match the corresponding versions and running npm install got everything working again.
I am using a physical device, in my case this solved the problem:
Uninstall the app
lsof -i :8081
kill -9 PID
Rebuild the app (react-native run-android or react-native run-ios)
In your build.gradle file add the following
implementation ("com.facebook.react:react-native:0.51.0") {
force = true;
}
replace 0.51.0 with the version in your package.json
Try installing the dependencies again. That worked for me-
1.) yarn/npm install
2.) yarn/npm start --reset-cache
For me it was due to react-native version in dependency section of package.json file. It was:
"dependencies": {
"expo": "^27.0.1",
"react": "16.3.1",
"react-native": "~0.55.0"
}
I chaged it to:
"dependencies": {
"expo": "^27.0.1",
"react": "16.3.1",
"react-native": "0.52.0"
}
Now it works fine.
In my case installing a new virtual device helped. Now I am using 1 device per app.
It happens sometimes when you try to run without closing the node server, in which the previous app was running, so try restarting React.To do so, just run the following commands:
1. To kill current processes
killall node -9
2. To Start React Native
react-native start
3. Then Run android
react-native run-android
For my case I'm facing it on iOS, and I've tried to reset and clear all cache using below command but failed too, despite many comments saying that the root cause is there is react packager running somewhere accidentally, I've restarted my mac and the problem still remained.
watchman watch-del-all && rm -rf node_modules/ && yarn cache clean && yarn install && yarn start --reset-cache
The solution is, to delete the build folder # /ios/build, then execute react-native run-ios solved it
I have tried the solutions above but adding this to AndroidManifest.xml seems to fix it.
android:usesCleartextTraffic="true"
For others with the same problem on iOS with CocoaPods:
I tried all of the solutions above, without luck. I have some packages with native dependencies in my project, and some of those needed pod modules being installed. The problem was that React was specified in my Podfile, but the React pod didn't automatically get upgraded by using react-native-git-upgrade.
The fix is to upgrade all installed pods, by running cd ios && pod install.
Expo users - make sure your app.json sdk version and package.json expo version are (may be equal) compatible to each other.
The fix we did was to make sure the ANDROID_HOME and PATH variables were set up prior to the build.
First, run the below two commands then the build the app for the device.
export ANDROID_HOME=/Users/username/MyFiles/applications/androidsdk
export PATH=$PATH:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools
This is working for me :
react-native start --reset-cache
I also had this issue using Expo and iOS Simulator. What worked for me was erasing the Simulator in Hardware > Erase All Content and Settings...
I have got the same issue while building my react native app for android and I did the following which worked for me.
The "JavaScript version 0.50.1" in the error console is the react-native version in your package.json file. Make sure it is the same version as "Native version 0.50.0" in the error console.
I have Updated the react-native version to the "Native Version 0.50.0" as prompted in the error console.
Rebuild the app react-native run-android.
Possible Fix:
Delete the package-lock.json
Run: watchman watch-del-all && rm -rf $TMPDIR/react-* && rm -rf $TMPDIR/haste-map-react-native-packager-* && rm -rf node_modules/&& npm install
If the problem persists, try to execute the project directly from the Xcode
This worked for me.
In my case (NOT using expo & Android build)
package.json
"dependencies": {
"react": "16.3.1",
"react-native": "0.55.2"
}
And app.json
{
"sdkVersion": "27"
}
resolved the issue
I was trying to build and run a React Native app from WebStorm and ran into this problem. The simple solution for me was:
watchman watch-del-all
On macOS, if watchman is not already installed, install it using Homebrew:
brew install watchman
In my case, I changed the expo version manually. I got the same issue because I forgot to update sdkVersion in app.json and babel-preset-expo in package.json
After that run: expo r -c to clear cache and start the app.
This Answer is Published in 2020,
Fix this Error in 3 steps:
First step: I changed the value of expo in package.json file to the latest supported version, according to expo documents(visit here).
Second step: I changed the value of sdkVersion in app.json file to the same value of expo in package.json.( equal number to last step).
Third step : I changed the value of react-native in package.json file to the same value of React Native Version , according to expo documents(visit here).
now your ready to go.
use npm install to install specified version of dependencies and then npm start to run the project
I got this classing when TypeScript type definitions mismatched.
E.G react-native at 0.61.5 in dependencies and #types/react-native at 0.60.0 in devDependencies.
As soon as I updated devDependencies it worked. Didn't have to restart anything.
edit your package.json for your javascript version
"react-native": "^0.50.1",
after run
npm install
For me, who is running with a monorepo, there was a hidden react-native version inside yarn.lock. It was not present in any package.json, but was never deleted.
I removed that particular react-native version from yarn.lock, and did a
yarn install
This cleaned out alot of old stuff and made sure that things was working fine.
I just upgraded react-native version to 0.48.1 from 0.30 and I am facing a weird issue.
I fixed all the peer-dependencies for the libraries that I am using. then ran command,
react-native start
running above command starts packager. Now when I hit below url to generate jsbundle,
http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false
I am getting below error,
"message":"Ambiguous resolution: module '$PROJ_ROOT_DIR/index.android.js' tries to require 'react-native', but there are several files providing this module. You can delete or fix them:
$PROJ_ROOT_DIR/node_modules/jest-react-native/node_modules/react-native/package.json
$PROJ_ROOT_DIR/node_modules/react-native/package.json"
$PROJ_ROOT_DIR is my project directory path.
I don't have any '$PROJ_ROOT_DIR/node_modules/jest-react-native/node_modules/' directory in my setup.
I tried deleting node_modules directory then running npm install. but nothing changed.
I have also tried, clearing packager cache by running command,
ls -l $TMPDIR/react-*
but nothing happened.
Has anyone faced similar issue? any suggestions?
Thanks in advance!
In case anyone else facing same issue of similar issues, Clearing cache using below command worked for me.
npm start -- --reset-cache
I was trying react-native start -- --reset-cache command which does nothing(my bad.).