react-devtools 3.5.0 breaks new project

[sunnylqm]

reactDevTools.connectToDevTools is not a function

## Environment
  React Native Environment Info:
    System:
      OS: macOS High Sierra 10.13.6
      CPU: (8) x64 Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz
      Memory: 833.36 MB / 16.00 GB
      Shell: 5.3 - /bin/zsh
    Binaries:
      Node: 8.15.0 - /usr/local/bin/node
      Yarn: 1.12.3 - /usr/local/bin/yarn
      npm: 6.4.1 - /usr/local/bin/npm
      Watchman: 4.9.0 - /usr/local/bin/watchman
    SDKs:
      iOS SDK:
        Platforms: iOS 12.1, macOS 10.14, tvOS 12.1, watchOS 5.1
      Android SDK:
        API Levels: 22, 23, 24, 25, 26, 27, 28
        Build Tools: 23.0.1, 23.0.2, 23.0.3, 24.0.1, 25.0.0, 25.0.2, 25.0.3, 26.0.1, 26.0.2, 26.0.3, 27.0.3, 28.0.2
        System Images: android-25 | Google APIs Intel x86 Atom, android-27 | Google APIs Intel x86 Atom, android-28 | Google APIs Intel x86 Atom, android-28 | Google APIs Intel x86 Atom_64
    IDEs:
      Android Studio: 3.1 AI-173.4907809
      Xcode: 10.1/10B61 - /usr/bin/xcodebuild
    npmPackages:
      react: 16.6.3 => 16.6.3
      react-native: 0.57.8 => 0.57.8
    npmGlobalPackages:
      react-native-cli: 2.0.1
      react-native-create-library: 3.1.2
      react-native-debugger-open: 0.3.17
      react-native-git-upgrade: 0.2.7
      react-native-update-cli: 0.1.0

Description

Reproducible Demo

Just init a new project and you'll hit this issue

Workaround

Put the following in your package.json and run yarn (not npm, which does not support "resolutions") to force install the previous version:

  "resolutions": {
    "react-devtools-core": "3.4.3"
  }

Then close the current packager window, run yarn start --reset-cache.

Since the compiled js file changed a lot and we actually got an empty object in setupDevtools.js, so I suspect that something went wrong with build configuration, maybe related to facebook/react-devtools@28d36a2

cc @bvaughn @kelset @hramos

[Flatheadman]

same problem.

[ESXHandsome]

same problem.

[swushi]

Same issue on two different computers. Workaround without yarn on Windows?

[silencer07]

resolution did not work for me strangely enough, what i did is install this particular version as dev-dependency for the mean time

[trops]

still not working with the workarounds

[jamonholmgren]

Thanks for reporting! (Please don't comment with "same here" comments; just thumbs-up the issue and subscribe to updates if you want.)

[osamaqarem]

Same issue.
I decided to learn React Native today, and I struggled for ~3 hours thinking I did something wrong during the "Get Started" guide. I was about to open a new issue to get help... only to find this opened 2 hours ago. Quite the headache 😫

[ppv94]

i am also getting the same error what should i do resolve this error
i have tried this but i am getting same error
"resolutions": {
"react-devtools-core": "3.4.3"
}
what should i do to resolve this issue

[prav02]

I am facing same problems, but when I am trying to run the previous projects that I have created, they all run fine.

[MingFaiYau]

After i upgrade react native 0.54.x -> 0.57.8, i got this problem too.

In setupDevtools.js

const reactDevTools = require('react-devtools-core');
reactDevTools return is an Object, not a function , so get error...
So it may be the react-devtools-core/build/backend.js problem..

For my temp solution..
add checking before use reactDevTools or just remove this code..

    if (typeof reactDevTools === 'function') {
      reactDevTools.connectToDevTools({
        isAppActive,
        host,
        // Read the optional global variable for backward compatibility.
        // It was added in https://github.com/facebook/react-native/commit/bf2b435322e89d0aeee8792b1c6e04656c2719a0.
        port: window.__REACT_DEVTOOLS_PORT__,
        resolveRNStyle: require('flattenStyle'),
      });
    }

[jamonholmgren]

I would recommend rolling back to react-devtools-core@3.4.3. I was able to do this and it worked.

yarn add --dev react-devtools-core@3.4.3
or
npm install --save-dev react-devtools-core@3.4.3

I will note that this happened on a brand-new 0.57.7 project also.

God bless you

[chuckntaylor]

Same issues here. Reverting to react-devtools-core@3.4.3 as @jamonholmgren recommended got me back up and running. Thanks!