Excessive number of pending callbacks: 501

[mezalejandro]

React Native version:

System:
OS: macOS Mojave 10.14.6
CPU: (4) x64 Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz
Memory: 22.95 MB / 8.00 GB
Shell: 3.2.57 - /bin/bash
Binaries:
Node: 10.15.1 - /usr/local/bin/node
npm: 6.4.1 - /usr/local/bin/npm
Watchman: 4.9.0 - /usr/local/bin/watchman
SDKs:
iOS SDK:
Platforms: iOS 12.2, macOS 10.14, tvOS 12.2, watchOS 5.2
Android SDK:
API Levels: 22, 23, 24, 25, 26, 27, 28, 29
Build Tools: 27.0.3, 28.0.2, 28.0.3, 29.0.1, 29.0.2
System Images: android-23 | Google APIs Intel x86 Atom, android-28 | Google APIs Intel x86 Atom, android-28 | Google APIs Intel x86 Atom_64, android-28 | Google Play Intel x86 Atom, android-28 | Google Play Intel x86 Atom_64
IDEs:
Android Studio: 3.4 AI-183.6156.11.34.5692245
Xcode: 10.2.1/10E1001 - /usr/bin/xcodebuild
npmPackages:
react: 16.9.0 => 16.9.0
react-native: 0.61.5 => 0.61.5
npmGlobalPackages:
react-native-cli: 2.0.1
react-native-git-upgrade: 0.2.7

Steps To Reproduce

Describe what you expected to happen:

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

[esensei]

Same problem

[madhums]

Seems to be occurring in async functions with awaiting promises. Here's a test

[superandrew]

same issue here, not sure why

[roger-ngx]

maybe firebase caused the problem ?

[kriscarle]

I had this error because I was looping and queuing hundreds of promises like

await Promise.all(filesToDownload.map(url => fetch(url)))

not the best plan... from the code it looks this warning is fired when there are more than 500 things pending in the message queue that hands runtime async calls off to the native code. (I'm new to this code so just a quick interpretation)

react-native/Libraries/BatchedBridge/MessageQueue.js

Line 210 in ce1703a

'excessive-number-of-pending-callbacks',

I ended up switching to Bluebird's Promise.map() function that has a concurrency option to limit how many promises are called at a time http://bluebirdjs.com/docs/api/promise.map.html#map-option-concurrency or you could use Async's mapLimit() https://caolan.github.io/async/v3/docs.html#mapLimit

[stale]

Hey there, it looks like there has been no activity on this issue recently. Has the issue been fixed, or does it still require the community's attention? This issue may be closed if no further activity occurs. You may also label this issue as a "Discussion" or add it to the "Backlog" and I will leave it open. Thank you for your contributions.

[rahamin1]

This happens to me with RN 0.62.2, and didn't happen to me on earlier versions of RN (I upgraded from 0.59.9).

Is this going to be fixed?

[rahulje9]

This is happening to me with RN 0.63.2. I was on 0.61.5 and updated packages just 2 weeks before and this is a big issue for us since we are in production.

Edit - I had updated all the packages including navigation. the app just hangs while navigating between the screen via bottom tab bar. everything was working fine in 0.61.5 and react-navigation 4.x

[savioserra]

Still experiencing this on v63.2 (react-navigation v5). Any updates?