Numbers with underscore separators cause error on Android

[xavierstampslafont]

Summary

If a number has underscore separators in it, e.g. 1_000, it will cause this error on Android (both on emulator and on device): No identifiers allowed directly after numeric literal

It works fine on iOS. Ideally it should work for Android too!

Managed or bare workflow? If you have ios/ or android/ directories in your project, the answer is bare!

managed

What platform(s) does this occur on?

Android

SDK Version (managed workflow only)

No response

Environment

Expo CLI 4.1.3 environment info:
System:
OS: macOS 11.2
Shell: 5.8 - /bin/zsh
Binaries:
Node: 15.5.0 - /usr/local/bin/node
Yarn: 1.22.10 - /usr/local/bin/yarn
npm: 7.5.4 - /usr/local/bin/npm
Managers:
CocoaPods: 1.10.1 - /usr/local/bin/pod
SDKs:
iOS SDK:
Platforms: iOS 14.4, DriverKit 20.2, macOS 11.1, tvOS 14.3, watchOS 7.2
IDEs:
Android Studio: 4.1 AI-201.8743.12.41.7042882
Xcode: 12.4/12D4e - /usr/bin/xcodebuild
npmPackages:
expo: ~40.0.0 => 40.0.1
react: 16.13.1 => 16.13.1
react-dom: 16.13.1 => 16.13.1
react-native: https://github.com/expo/react-native/archive/sdk-40.0.1.tar.gz => 0.63.2
react-native-web: ~0.13.12 => 0.13.18
npmGlobalPackages:
expo-cli: 4.1.3
Expo Workflow: managed

Reproducible demo or steps to reproduce from a blank project

https://snack.expo.io/ns4xL2JLk

[AdamJNavarro]

Hey @xavierstampslafont, this falls out of the scope of Expo but rather deals with JavaScript's implementation itself.

[xavierstampslafont]

Is it because of different JS engines being used for Android vs iOS?

If you're aware of where else I can raise this issue, I'd appreciate any help!