[Regression 0.62.2] requestIdleCallback is never called on iOS

[Freddy03h]

Description

requestIdleCallback is never called on iOS. On a debug or release mode the behavior is the same. On Android it still work as expected.
The only way for requestIdleCallback to be called on iOS is by providing an timeout option (but all called of requestIdleCallback will be with didTimeout…).

It's a regression in 0.62.X, it worked well on 0.61.5 (and since, at least, 0.47.X on my own app).

React Native version:

System:
    OS: macOS 10.15.4
    CPU: (4) x64 Intel(R) Core(TM) i5-6267U CPU @ 2.90GHz
    Memory: 21.85 MB / 16.00 GB
    Shell: 5.7.1 - /bin/zsh
  Binaries:
    Node: 12.14.1 - /var/folders/68/7qlptmf573d5fzhxlhc6tfvm0000gn/T/yarn--1586712574681-0.7718023604103352/node
    Yarn: 1.19.1 - /var/folders/68/7qlptmf573d5fzhxlhc6tfvm0000gn/T/yarn--1586712574681-0.7718023604103352/yarn
    npm: 6.13.4 - ~/.nvm/versions/node/v12.14.1/bin/npm
    Watchman: 4.9.0 - /usr/local/bin/watchman
  Managers:
    CocoaPods: 1.8.4 - /Users/freddy/.rbenv/shims/pod
  SDKs:
    iOS SDK:
      Platforms: iOS 13.4, DriverKit 19.0, macOS 10.15, tvOS 13.4, watchOS 6.2
    Android SDK:
      API Levels: 23, 24, 25, 26, 27, 28, 29
      Build Tools: 23.0.1, 23.0.3, 24.0.3, 25.0.0, 25.0.2, 25.0.3, 26.0.1, 26.0.2, 26.0.3, 27.0.3, 28.0.1, 28.0.2, 28.0.3, 29.0.2, 29.0.3
      System Images: android-23 | Intel x86 Atom, android-23 | Intel x86 Atom_64, android-23 | Google APIs ARM EABI v7a, android-23 | Google APIs Intel x86 Atom, android-23 | Google APIs Intel x86 Atom_64, android-25 | Google APIs ARM EABI v7a, android-25 | Google APIs Intel x86 Atom, android-25 | Google APIs Intel x86 Atom_64, android-25 | Google Play Intel x86 Atom, android-26 | Google APIs Intel x86 Atom, android-26 | Google Play Intel x86 Atom, android-27 | Google APIs Intel x86 Atom, android-28 | Google APIs Intel x86 Atom
      Android NDK: Not Found
  IDEs:
    Android Studio: 3.1 AI-173.4819257
    Xcode: 11.4/11E146 - /usr/bin/xcodebuild
  Languages:
    Java: 1.8.0_111 - /usr/bin/javac
    Python: 2.7.16 - /usr/bin/python
  npmPackages:
    @react-native-community/cli: Not Found
    react: 16.11.0 => 16.11.0
    react-native: 0.62.2 => 0.62.2
  npmGlobalPackages:
    *react-native*: Not Found

Steps To Reproduce

1. Create a fresh new react-native app and install the js dependencies and pods. (I used https://github.com/react-native-community/rn-diff-purge/tree/release/0.62.2/RnDiffApp)
2. On App.js, inside or outside a function component:

requestIdleCallback(()=> {
  console.log("Never called on iOS, only on Android");
});

Expected Results

Expect to requestIdleCallback work as expected.

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

Expo/Snack is not yet on 0.62, the best way is to create a new project with react native cli or by cloning https://github.com/react-native-community/rn-diff-purge/tree/release/0.62.2/RnDiffApp

Thank you

[svenlombaert]

I can confirm that I'm running into this issue as well, thinking it was a swr issue.

[svenlombaert]

If anyone runs into the issue, you can just polyfill it with something like this for now:

window.requestIdleCallback =
    function(cb) {
        var start = Date.now();
        return setTimeout(function() {
            cb({
                didTimeout: false,
                timeRemaining: function() {
                    return Math.max(0, 50 - (Date.now() - start));
                },
            });
        }, 1);
    };

Taken from https://github.com/pladaria/requestidlecallback-polyfill, but the package itself won't work since window.requestIdleCallback is defined by react-native. So you just have to remove that if.

[matt-oakes]

@Freddy03h @svenlombaert I have found the issue that's causing this and submitted a PR to fix it. It's easy to fix this yourself using patch-package.

[Nantris]

I hope this can get fixed? It's pretty confusing that the function is defined and everything seems right, but then the code just stops executing when we try to use the function. Took me a bit to realize what the issue was since it works fine on Android.