+1

I am getting this on 0.46

Alright seems like I've managed to fix this on RN 0.45.1
Just clean everything:

watchman watch-del-all
rm -rf $TMPDIR/react-*
rm -rf yarn.lock
rm -rf ./node_modules
yarn install

Worked for me, also unlinking and linking might help.

Face same problem when creating new project with Ignite.

• react-native -V 0.45.1
• node -v v7.10.0
• npm -v 4.2.0
• yarn --version 0.27.5
• react-native run-ios

@Amurmurmur suggestion didn't help.

Found the problem what I had (with new project generated with Ignite).

The error were pointing in my project to line import rootSaga from '../Sagas/' which contain export like this:

export default function * root () {
  yield [
    // ... snip ....
  ]
}

After changing it to this started to work:

const root = function * root () {
  yield [
    // .... snip ....
  ]
}
export default root

I'm not yet familiar with the ES6 generator functions and require support for them, but at least now I can continue. And have to say that the error were pointing to the place where the invalid export were. I hope this helps someone.

infinitered/ignite#1098 (comment)

Wasn't this fixed here? e7c1cf5

So this won't roll out till 0.47?

Tried to fix with the suggested Saga solution, its surely something to do with saga because when I comment out saga implementation in my configureStore, the error is gone however trying suggested solution doesnt work for me. :/

@grabbou @GantMan @ernoaapa
Alright guys, figured out the problem
downgraded babel-preset-react-native form 2.1.0 to 2.0.0 all works fine on Android/iOS
Though once upgraded to 0.46 the error comes back.
As for RN 0.47-rc.0, most packages I have linked, wont work due to some changes to the api of the react-native I guess because they will throw errors such as:

:react-native-blur:compileReleaseJavaWithJavac - is not incremental (e.g. outputs have changed, no previous execution, etc.).
/Users/amurmurmur/exampleapp/node_modules/react-native-blur/android/src/main/java/com/cmcewen/blurview/BlurViewPackage.java:23: error: method does not override or implement a method from a supertype
    @Override
    ^
Note: /Users/amurmurmur/exampleapp/node_modules/react-native-blur/android/src/main/java/com/cmcewen/blurview/BlurringView.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
1 error
:react-native-blur:compileReleaseJavaWithJavac FAILED

@Amurmurmur I am still seeing the issue on 0.45.1 even after downgrading babel. I wonder how much node and npm versions might be affecting which fixes work and which ones don't.
node: v8.1.0
npm: 5.1.0
OS: macOS Sierra 10.12.5

@kcalmes Make sure you reset react-native packager after you've downgraded babel with:

npm start -- --reset-cache

That did the trick, I previously deleted the node_modules dir, but I didn't realize I missed the other cache. Thanks for your help @Amurmurmur!

@facebook-github-bot close

@brentvatne tells me to close this issue. If you think it should still be opened let us know why.

Still experiencing this with 0.46.1 and babelrc on both 2.0.0 and 2.1.0. Tried all the things done here but it doesnt fix it. Why was this closed @brentvatne @grabbou

@vongohren Double make sure you reset the packager, Im using react-native 0.46.1 and babel at 2.0.0 all good on both platforms Debug/Release builds.
Please make sure you run

watchman watch-del-all
rm -rf ./node_modules
rm -rf $TMPDIR/react-*
npm i babel-preset-react-native@2.0.0 -D -S
npm install
npm start -- --reset-cache
react-native run-ios

Also make sure you reset your android/ios emulator/simulator, delete both android/ios build folders.

Loool, this is what I have done all the way, but I did not reset the emulator and delete the build folder. Seemed to help, thanks man. But can anyone answere why this happens? @grabbou @brentvatne

Edit: This did solve my android problem, but produces different iOS problems. What are the different clearing options of ios? Clear derivated folders? Pod install again. What else @Amurmurmur ? Im running Cocoapods and swift on iOS

Downgrade babel-preset-react-native to 2.0.0 work for me too. But why 2.1.0 don't work?

Downgrading worked for me, but I'd also like to know what the issue actually is and what a real fix is.

Running a completly new project, that is not dependent on cocoapods or swift, works out of the box. I did not try to add all my dependencies but that could be a test case.

@vongohren Indeed the fresh project will work for you however once you start using babel features such as export/import you will face the problem with babel-preset-react-native 2.1.0
This is a relevant issue #14933

Same issue here, from react-native version 0.45.1 on Linux subsystem for Windows, downgrading babel-preset and @Amurmurmur's method doesn't work

@HelloEdit
But it works, can you share an example project where the problem occurs for you ?
It works fine on my side no matter RN 0.45.1 or 0.46.1 all still.

I had the same issue using 2.1.0 and downgraded to 2.0.0 which fixed the issue.

Now for some reason it doesn't work anymore with 2.0.0 😕

LE : apparently worked after a restart, maybe something was cached...

@fengshuo thanks, but already tried and didn't work.
I'm with Expo create-react-native-app, maybe it adds some to this issue

Same here, also coming from Expo create-react-native-app.

@fengshuo @webwelten I believe you are going to have to wait and see if this gets updated in SDK 21, or forbabel-preset-expo to get updated... or you can try and not use the default crna .babelrc and set the preferred babel preset. You will have to account for @expo/vector-icons though; see this comment and the one below it.

Just to let you know that i solved ejecting from Expo

I'm still having this issue, even after following all of the solutions presented in this thread, including @Amurmurmur 's solution and resetting my terminal / local server, even resetting my computer. It started happening for me after I moved my project root from my user folder to my documents, but the issue persists even if it's moved back so I'm not sure that's the cause.

I can't help but notice my main.jsbundle in xcode is red, which usually indicates it's missing. I'd try to re-add it to my project, but I can't find any resources online that indicate where the main.jsbundle is.

Here's my full Xcode log:

undefined is not an object (evaluating 'regeneratorRuntime.mark')
2017-09-13 11:47:23.171 [fatal][tid:com.facebook.react.ExceptionsManagerQueue] Unhandled JS Exception: undefined is not an object (evaluating 'regeneratorRuntime.mark')
2017-09-13 11:47:23.176 [info][tid:com.facebook.react.JavaScript] Running application "APP" with appParams: {"rootTag":1,"initialProps":{}}. __DEV__ === true, development-level warning are ON, performance optimizations are OFF
2017-09-13 11:47:23.176 [error][tid:com.facebook.react.JavaScript] Application APP has not been registered.

Hint: This error often happens when you're running the packager (local dev server) from a wrong folder. For example you have multiple apps and the packager is still running for the app you were working on before.
If this is the case, simply kill the old packager instance (e.g. close the packager terminal window) and start the packager in the correct app folder (e.g. cd into app folder and run 'npm start').

This error can also happen due to a require() error during initialization or failure to call AppRegistry.registerComponent.


2017-09-13 11:47:23.197 [fatal][tid:com.facebook.react.ExceptionsManagerQueue] Unhandled JS Exception: Application APP has not been registered.

Hint: This error often happens when you're running the packager (local dev server) from a wrong folder. For example you have multiple apps and the packager is still running for the app you were working on before.
If this is the case, simply kill the old packager instance (e.g. close the packager terminal window) and start the packager in the correct app folder (e.g. cd into app folder and run 'npm start').

This error can also happen due to a require() error during initialization or failure to call AppRegistry.registerComponent.

Currently running on the latest version of React Native (0.48.3) and the latest babel-preset-react-native (3.0.2).

Also to address the registration complaint, my app has been running fine on previous versions of React Native and I haven't changed the registration code in either my index.ios.js or my index.android.js.

My index.ios.js and index.android.js:

import {
  AppRegistry,
} from 'react-native';

import Home from "./src/Home";

AppRegistry.registerComponent('APP', () => Home);

This should be correct, yeah? So I have no clue why it's suddenly getting this complaint too. Although I suspect it's the result of the first error undefined is not an object (evaluating 'regeneratorRuntime.mark')

I'm using react-native 0.48.3 and what fixed it for me is the following steps:

1. I created a .babelrc file with the following contents in the root of the project

{
  "presets": ["react-native"]
}

2. I installed babel-preset-react-native@3.0.2
3. I ran node node_modules/react-native/local-cli/cli.js start --reset-cache

The problem is now gone.

@SudoPlz How do I create a .babelrc file?

@arminsal1 Open a terminal, cd to your project dir and type touch .babelrc

@SudoPlz Your solution solved my problem, thank you so much!

I'm glad, :)

@SudoPlz, thanks. This did the trick finally. Can you explain also why only after this it starts to work?

@ernoaapa Thanks

watchman watch-del-all
rm -rf ./node_modules
rm -rf $TMPDIR/react-*
npm i babel-preset-react-native@2.0.0 -D -S
npm install
npm start -- --reset-cache
react-native run-ios

From：
https://stackoverflow.com/questions/45155249/when-using-redux-saga-with-react-native-web-we-get-an-error-cannot-read-propert

ps:
First remove package-lock.json or yarn.lock because other packages may also use babel-preset-react-native, and you can open the lock file to check that they depend on the babel-preset-react-native, which may be the locked version 2.1.0

I ran into this error using babel-preset-expo and fixed it by switching to babel-preset-react-native:

yarn add babel-preset-react-native

in .babelrc:

"presets": [
    "babel-preset-react-native"
  ]

@csuermann Thanks! That worked for me!

what sdk version were you using @csuermann? this shouldn't be a problem with latest version of expo

@brentvatne:
"sdkVersion": "21.0.0"

@brentvatne I am running into the same issue with sdkVersion "22.0.0"

It seems that the version of babel-preset-react-native that babel-preset-expo depends on is 2.1.0. Per what I've read above, this may be causing the problem (and downgrading to 2.0.0 is a potential solution)

Edit:

I was able to get around the issue without changing any dependencies, just had to switch up how I write my sagas:

Went from

function* listenForSignUpUser() {
}

to

const listenForSignUpUser = function* () {
}

I have a bug in the Expo's Font.loadAsync dependency. It uses async and I get this error:

Please help me. Im on time pressure. Thanks

@SudoPlz
node node_modules/react-native/local-cli/cli.js start --reset-cache + "the sagas export refactoring" work for me !! 😁

"babel-preset-react-native": "^4.0.0",`
"react-native": "^0.50.4",
"react": "16.0.0"

Please note that this also error might also happen with old code (react native 0.44 and about as old babel-preset-react-native) if using Node >= 9.

A fix is to use any Node <9 version which might be a lot easier than upgrading react native.

@Pokute I downgraded Node from 9 to 8, and it worked for me!
Thank you!!!