[...Array(5).keys()] not working in Android

[James2516]

Is this a bug report?

Yes

Have you read the Contributing Guidelines?

Yes

Environment

OS: macOS Sierra 10.12.6
Node: 9.8.0
Yarn: 1.5.1
npm: 5.6.0
Watchman: 4.7.0
Xcode: Xcode 9.2 Build version 9C40b
Android Studio: 3.0 AI-171.4443003

Packages: (wanted => installed)
react: ^16.3.0-alpha.1 => 16.3.0-alpha.2
react-native: 0.54.2 => 0.54.2

Steps to Reproduce

console.log([...Array(2).keys()]) does not produce [0, 1].

1. Run https://snack.expo.io/SJT6PCPPZ on Android (works)
2. Run https://snack.expo.io/H1elODwPb on Android (nothing rendered on screen)
   Additional note: both works on iOS.

Expected Behavior

https://snack.expo.io/H1elODwPb should render data on screen

Actual Behavior

https://snack.expo.io/H1elODwPb renders nothing on screen

Reproducible Demo

see above

[react-native-bot]

Thanks for posting this! It looks like your issue may be missing some necessary information. Can you run react-native info and edit your issue to include these results under the Environment section?

Thank you for your contributions.

[hramos]

Seems like a JavaScriptCore issue (this is the JavaScript engine used by React Native).

As a point of comparison, using V8 we get identical results:

[...Array(5).keys()].map(String)
(5) ["0", "1", "2", "3", "4"]
['0', '1', '2', '3', '4'].map(String)
(5) ["0", "1", "2", "3", "4"]

IIRC, we use a fork of the JSC on Android which diverged from what iOS provides.