(cherry-pick) fix: Keyframe LA easing not working properly on web #7991
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## Summary Fixes: #7950 This PR fixes the problem with easings configured via the custom `Keyframe` layout animation on web. The problem results from the adopted convention in which we expect the keyframe easing to be defined in the second keyframe of the keyframes pair between which the easing should be applied. This is different from how CSS animations work and slightly confusing but, since changing this behavior will introduce a breaking change, I decide to just adjust the web implementation to shift keyframe easings one keyframe before, which in result makes it possible to create a valid CSS animation from out LA `Keyframe` object. ## Test example Before this PR the custom easing was not applied and the animation progressed with a default easing. | Before | After | |-|-| | <video src="https://github.com/user-attachments/assets/15629df8-f9d1-4b34-b119-eb325b30ee97" /> | <video src="https://github.com/user-attachments/assets/a7145b3b-cefa-4dbb-8eb5-a0454bb0346b" /> | <details> <summary>Source code</summary> ```tsx import React from 'react'; import { Easing, StyleSheet, Text } from 'react-native'; import Animated, { Keyframe } from 'react-native-reanimated'; export default function EmptyExample() { const keyframe = new Keyframe({ 0: { transform: [{ translateY: `100%` }], }, 100: { transform: [{ translateY: `0%` }], easing: Easing.exp, }, }); return ( <Animated.View entering={keyframe.duration(1000)} style={styles.box}> <Text>Some text</Text> </Animated.View> ); } const styles = StyleSheet.create({ box: { width: 100, height: 100, backgroundColor: 'red', }, }); ``` </details>
15 tasks
m-bert
approved these changes
Aug 4, 2025
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Cherry-pick of the #7978