Description
Description
Simulator.Screen.Recording.-.iPhone.16.Pro.-.2025-06-06.at.02.15.23.mp4
As visible from the video i have 2 text inputs rendered with a map with stable keys, i focus the one on top and then swap them and they swap keeping the focus on the active one which is what i need. If then i do the same but swapping the focused input from bottom to top it looses focus.
I dived a bit into the RN code and figured out that when going from bottom top top it gets unmounted and then remounted since Differentiator.cpp generated a remove and an insert commands. I understand nothing about how the diffing algo works so i have no idea if this is intendend behaviour or not but it's blocking me with this focus loss problem
I'm reporting the issue on iOS since is where i investigated it the most, on android it works bad as well but in a bit of a different way, with the same code i added in the reproduce section you can see the problem on android as well
Steps to reproduce
import { useState } from "react";
import { View, StyleSheet, TextInput, Button } from "react-native";
export default function TestPage() {
const [keys, setKeys] = useState<string[]>(["1", "2"]);
function swap() {
const newKeys = [...keys];
const temp = newKeys[0];
newKeys[0] = newKeys[1];
newKeys[1] = temp;
setKeys(newKeys);
}
return (
<View style={styles.container}>
{keys.map((key, index) => (
<TextInput
key={key}
style={styles.input}
defaultValue={key == "1" ? "First input" : "Second input"}
/>
))}
<Button title="Swap" onPress={swap} />
</View>
);
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: "center",
alignItems: "center",
},
input: {
height: 40,
width: "80%",
borderColor: "gray",
borderWidth: 1,
marginBottom: 10,
paddingHorizontal: 10,
},
});React Native Version
0.79.2
Affected Platforms
Runtime - Android, Runtime - iOS
Output of npx @react-native-community/cli info
System:
OS: macOS 15.3.2
CPU: (10) arm64 Apple M1 Pro
Memory: 864.30 MB / 32.00 GB
Shell:
version: "5.9"
path: /bin/zsh
Binaries:
Node:
version: 20.15.1
path: ~/.nvm/versions/node/v20.15.1/bin/node
Yarn:
version: 1.22.22
path: ~/.nvm/versions/node/v20.15.1/bin/yarn
npm:
version: 10.7.0
path: ~/.nvm/versions/node/v20.15.1/bin/npm
Watchman:
version: 2025.04.28.00
path: /opt/homebrew/bin/watchman
Managers:
CocoaPods:
version: 1.16.2
path: /Users/ipla/.rvm/gems/ruby-3.3.1/bin/pod
SDKs:
iOS SDK:
Platforms:
- DriverKit 24.4
- iOS 18.4
- macOS 15.4
- tvOS 18.4
- visionOS 2.4
- watchOS 11.4
Android SDK:
Android NDK: 22.1.7171670
IDEs:
Android Studio: 2024.2 AI-242.23726.103.2422.12816248
Xcode:
version: 16.3/16E140
path: /usr/bin/xcodebuild
Languages:
Java:
version: 21.0.6
path: /usr/bin/javac
Ruby:
version: 3.3.1
path: /Users/ipla/.rvm/rubies/ruby-3.3.1/bin/ruby
npmPackages:
"@react-native-community/cli": Not Found
react:
installed: 19.0.0
wanted: 19.0.0
react-native:
installed: 0.79.2
wanted: 0.79.2
react-native-macos: Not Found
npmGlobalPackages:
"*react-native*": Not Found
Android:
hermesEnabled: Not found
newArchEnabled: Not found
iOS:
hermesEnabled: Not found
newArchEnabled: Not found
Stacktrace or Logs
Doesn't apply
MANDATORY Reproducer
https://snack.expo.dev/@ipla/rn-swap-reproducer