react / react/metro

Metro bundle extremely slow and gets stuck with babel v7.17.x

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📦Bundler Needs: Triage :mag:
Dominant language
JavaScript
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Description

Description

I had a huge issue bundling the app for development and production as soon as I updated the following packages to the latest version:

"@babel/core": "7.16.12",
"@babel/plugin-proposal-decorators": "7.16.7",
"@babel/runtime": "7.16.7",
"babel-jest": "27.5.1",
"metro-react-native-babel-preset": "0.67.0",

Basically, one of the mentioned packages is causing metro to bundle extremely slow and finally get stuck at approximately 90%.
After I reverted the package.json back to an older version, it still didn't help because of the ^. I had to remove ^ from the packages I mentioned, and it was back to normal.

I'm guessing it's a babel issue (I also updated React Native to 0.67.3), but I think you guys should know, I spent all day yesterday trying to resolve this (I also looked on here) without any luck.

Also, after all of that I was required to install 2 additional packages:

"@babel/plugin-transform-arrow-functions": "7.16.7",
"@babel/plugin-transform-shorthand-properties": "7.16.7",
Version

0.67.3

Output of npx react-native info
System:
    OS: macOS 12.2.1
    CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
    Memory: 606.40 MB / 16.00 GB
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 16.14.0 - /usr/local/bin/node
    Yarn: 1.22.17 - /usr/local/bin/yarn
    npm: 8.5.2 - /usr/local/bin/npm
    Watchman: 2022.02.21.00 - /usr/local/bin/watchman
  Managers:
    CocoaPods: 1.11.2 - /usr/local/bin/pod
  SDKs:
    iOS SDK:
      Platforms: DriverKit 21.2, iOS 15.2, macOS 12.1, tvOS 15.2, watchOS 8.3
    Android SDK:
      API Levels: 30, 31
      Build Tools: 30.0.2, 31.0.0, 32.0.0
      System Images: android-30 | Google Play Intel x86 Atom
      Android NDK: Not Found
  IDEs:
    Android Studio: Bumblebee 2021.1.1 Patch 2 Bumblebee 2021.1.1 Patch 2
    Xcode: 13.2.1/13C100 - /usr/bin/xcodebuild
  Languages:
    Java: 1.8.0_292 - /usr/bin/javac
  npmPackages:
    @react-native-community/cli: Not Found
    react: 17.0.2 => 17.0.2
    react-native: 0.67.3 => 0.67.3
    react-native-macos: Not Found
  npmGlobalPackages:
    *react-native*: Not Found
Steps to reproduce

Running npx react-native start after updating all the packages to the latest version.

Snack, code example, screenshot, or link to a repository

No response

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the package versions in package.json and reproduce the problem by running npx react-native start with the listed Babel and React Native versions. Compare bundling with the caret ranges and pinned versions, then narrow down which package causes the stall; done means the regression is identified and bundling no longer gets stuck near 90%.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, react-native
Domain
build-system, devtools
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
28/100

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