Intl library functions become undefined on iOS in React Native v0.74.x with Hermes

[rcluca]

Old Version

0.73.8

New Version

0.74.1

Description

The built-in Intl library seems to lose support on iOS with Hermes in v0.74.x, specifically methods like Intl.DateTimeFormat.formatToParts() become undefined. Android (with and without Hermes) and Web work as expected.

Steps to reproduce

1. Install the app with yarn install and pod install in the ios repo
2. Add a reference to the Intl library and use it, for example, add the following to the App.tsx file:
   const formatter = new Intl.DateTimeFormat(); console.log(formatter.formatToParts(new Date()));
3. Run the app with react-native start and react-native run-ios.
4. See the app crash when loading the App component.

Affected Platforms

Runtime - iOS

Output of npx react-native info

System:
  OS: macOS 13.6.6
  CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
  Memory: 102.14 MB / 32.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 19.4.0
    path: /usr/local/bin/node
  Yarn:
    version: 3.6.4
    path: /usr/local/bin/yarn
  npm:
    version: 9.2.0
    path: /usr/local/bin/npm
  Watchman:
    version: 2023.01.16.00
    path: /usr/local/bin/watchman
Managers:
  CocoaPods:
    version: 1.15.2
    path: /Users/raulluca/.rbenv/shims/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 23.2
      - iOS 17.2
      - macOS 14.2
      - tvOS 17.2
      - visionOS 1.0
      - watchOS 10.2
  Android SDK: Not Found
IDEs:
  Android Studio: 2022.3 AI-223.8836.35.2231.10811636
  Xcode:
    version: 15.2/15C500b
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.11
    path: /usr/bin/javac
  Ruby:
    version: 2.7.6
    path: /Users/raulluca/.rbenv/shims/ruby
npmPackages:
  "@react-native-community/cli": Not Found
  react: Not Found
  react-native: Not Found
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: false
iOS:
  hermesEnabled: true
  newArchEnabled: false

Stacktrace or Logs

LOG  Running "ReproducerApp" with {"rootTag":1,"initialProps":{"concurrentRoot":false}}
 ERROR  TypeError: formatter.formatToParts is not a function (it is undefined)

This error is located at:
    in Section (created by App)
    in RCTView (created by View)
    in View (created by App)
    in RCTScrollContentView (created by ScrollView)
    in RCTScrollView (created by ScrollView)
    in ScrollView (created by ScrollView)
    in ScrollView (created by App)
    in RCTSafeAreaView (created by App)
    in App
    in RCTView (created by View)
    in View (created by AppContainer)
    in RCTView (created by View)
    in View (created by AppContainer)
    in AppContainer
    in ReproducerApp(RootComponent), js engine: hermes

Reproducer

https://github.com/rcluca/intl-hermes

Screenshots and Videos

[dmytrorykun]

This regression was first introduced in 0.74.0-nightly-20231018-191c3deae

[dmytrorykun]

This regression was introduced here facebook/hermes@c5a633f

cc @cipolleschi

[cipolleschi]

We picked the revert for 0.74.2.

[thespacemanatee]

@cipolleschi, can we pick this revert for 0.76 as well? It has started to break for us again, and we use it in our projects. Are we advised to use alternative APIs?

[cipolleschi]

@thespacemanatee I'm sorry for that. We will revert the commit commit on 0.76 again. Meanwhile, I'll try to find a more sustainable long term solution.

[maksim-romanov]

same issue for me, formatRange is undefined too

[G2Jose]

Hey this still seems to be a problem (in react native 0.79.3)