`transition-property: scale` names `scale`, while the style that changes is `transform`

Start with the transition-property case in src/compiler/declarations.ts, then trace how parseMargin, parseTranslate and the other parsers determine written style keys. Run the reproducer test src/__tests__/native/transition-key-written-elsewhere.test.tsx from the linked branch. Done means transitions name the keys produced by the declarations and keep duration, delay and timing function lists aligned.

Before submitting a new issue

• I tested using the latest version of the library, as the bug might be already fixed.
• I tested using a supported version of react native.
• I checked for possible duplicate issues, with possible answers.

Bug summary

A transition names the style key it animates, but the compiler writes some properties under other keys: translate, rotate and scale into transform, and a non-uniform margin into its sides. So transition-property: scale names scale while the style that changes is transform, and Reanimated's transition, which follows the names it is given, animates nothing.

scale: transitionProperty ["scale"], style keys ["transform"]
translate: transitionProperty ["translate"], style keys ["transform"]
margin: transitionProperty ["margin"], style keys ["marginTop","marginBottom","marginLeft","marginRight"]

All three fail. Expected: a transition on each property names the keys it is written to, repeating its duration, delay and timing function for each so the lists stay aligned. addTransitionValue's transition-property case (src/compiler/declarations.ts) maps one name to one key, while the keys a shorthand or translate, rotate and scale write come from their parsers (parseMargin, parseTranslate and the rest).

Library version

main at 2421ea7 (0.0.0-nightly.2421ea7)

Environment info

System:
  OS: Windows 11 10.0.26300
  CPU: "(32) x64 AMD Ryzen 9 9950X3D 16-Core Processor          "
  Memory: 155.26 GB / 255.67 GB
Binaries:
  Node:
    version: 26.12.1
    path: C:\Program Files\nodejs\node.EXE
  Yarn:
    version: 4.9.2
    path: C:\Users\<user>\AppData\Roaming\npm\yarn.CMD
  npm:
    version: 12.2.1
    path: C:\Program Files\nodejs\npm.CMD
  Watchman: Not Found
SDKs:
  Android SDK:
    API Levels:
      - "33"
      - "35"
      - "35"
      - "35"
      - "36"
      - "37"
    Build Tools:
      - 35.0.0
      - 36.0.0
      - 36.1.0
      - 37.0.0
    System Images:
      - android-26 | Google APIs Intel x86_64 Atom
      - android-28 | Google APIs Intel x86_64 Atom
      - android-29 | Google APIs Intel x86_64 Atom
      - android-30 | Google APIs Intel x86_64 Atom
      - android-31 | Google APIs Intel x86_64 Atom
      - android-32 | Google APIs Intel x86_64 Atom
      - android-33 | Google APIs Intel x86_64 Atom
      - android-34 | Google APIs Intel x86_64 Atom
      - android-35 | Google APIs Intel x86_64 Atom
      - android-36.1 | Google Play Intel x86_64 Atom
      - android-36.1 | Pre-Release 16 KB Page Size Google Play Intel x86_64 Atom
      - android-37.0 | Google APIs Intel x86_64 Atom
    Android NDK: Not Found
  Windows SDK: Not Found
IDEs:
  Android Studio: AI-262.9437.185.2621.16467767
  Visual Studio: Not Found
Languages:
  Java:
    version: 17.0.20.1
    path: C:\Program Files\Microsoft\jdk-17.0.20.101-hotspot\bin\javac.EXE
  Ruby: Not Found
npmPackages:
  "@react-native-community/cli": Not Found
  react:
    installed: 19.2.3
    wanted: 19.2.3
  react-native:
    installed: 0.86.3
    wanted: 0.86.3
  react-native-windows: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: Not found
  newArchEnabled: Not found
iOS:
  hermesEnabled: Not found
  newArchEnabled: Not found

Steps to reproduce

1. Clone the reproducer branch, which is main at 2421ea7 with one file added, src/__tests__/native/transition-key-written-elsewhere.test.tsx, and install:

   git clone --branch repro/532-transition-names-a-key-the-compiler-writes-elsewhere https://github.com/YevheniiKotyrlo/react-native-css
   cd react-native-css
   yarn install
   

2. Run yarn jest src/__tests__/native/transition-key-written-elsewhere.test.tsx.

src/__tests__/native/transition-key-written-elsewhere.test.tsx:

import { StyleSheet } from "react-native";

import { render, screen } from "@testing-library/react-native";
import { View } from "react-native-css/components/View";
import { registerCSS, testID } from "react-native-css/jest";

jest.mock("../../native/reanimated", () => ({
  animatedComponentFamily: (component: unknown) => component,
}));

test.each([
  ["scale", "scale: 2"],
  ["translate", "translate: 10px"],
  ["margin", "margin: 1px 2px"],
])("a transition on %s names a key the style holds", (property, declaration) => {
  registerCSS(`.a { transition-property: ${property}; transition-duration: 1s; ${declaration}; }`);
  render(<View testID={testID} className="a" />);
  const style = StyleSheet.flatten(screen.getByTestId(testID).props.style) as Record<string, unknown>;
  const keys = Object.keys(style).filter((key) => !key.startsWith("transition"));
  console.log(`${property}: transitionProperty ${JSON.stringify(style.transitionProperty)}, style keys ${JSON.stringify(keys)}`);
  expect(keys).toEqual(expect.arrayContaining(style.transitionProperty as string[]));
});

Expected: transition-property: scale animates the style that changes, transform, and the same for the other properties the compiler writes under other keys.

Actual: the transition names scale, a key the style never changes, so nothing animates.

  console.log
    scale: transitionProperty ["scale"], style keys ["transform"]
      at log (src/__tests__/native/transition-key-written-elsewhere.test.tsx:20:11)
  console.log
    translate: transitionProperty ["translate"], style keys ["transform"]
      at log (src/__tests__/native/transition-key-written-elsewhere.test.tsx:20:11)
  console.log
    margin: transitionProperty ["margin"], style keys ["marginTop","marginBottom","marginLeft","marginRight"]
      at log (src/__tests__/native/transition-key-written-elsewhere.test.tsx:20:11)
FAIL src/__tests__/native/transition-key-written-elsewhere.test.tsx
  × a transition on scale names a key the style holds (29 ms)
  × a transition on translate names a key the style holds (5 ms)
  × a transition on margin names a key the style holds (2 ms)
  ● a transition on scale names a key the style holds
    expect(received).toEqual(expected) // deep equality
    Expected: ArrayContaining ["scale"]
    Received: ["transform"]
      19 |   const keys = Object.keys(style).filter((key) => !key.startsWith("transition"));
      20 |   console.log(`${property}: transitionProperty ${JSON.stringify(style.transitionProperty)}, style keys ${JSON.stringify(keys)}`);
    > 21 |   expect(keys).toEqual(expect.arrayContaining(style.transitionProperty as string[]));
         |                ^
      22 | });
      23 |
      at toEqual (src/__tests__/native/transition-key-written-elsewhere.test.tsx:21:16)
  ● a transition on translate names a key the style holds
    expect(received).toEqual(expected) // deep equality
    Expected: ArrayContaining ["translate"]
    Received: ["transform"]
      19 |   const keys = Object.keys(style).filter((key) => !key.startsWith("transition"));
      20 |   console.log(`${property}: transitionProperty ${JSON.stringify(style.transitionProperty)}, style keys ${JSON.stringify(keys)}`);
    > 21 |   expect(keys).toEqual(expect.arrayContaining(style.transitionProperty as string[]));
         |                ^
      22 | });
      23 |
      at toEqual (src/__tests__/native/transition-key-written-elsewhere.test.tsx:21:16)
  ● a transition on margin names a key the style holds
    expect(received).toEqual(expected) // deep equality
    Expected: ArrayContaining ["margin"]
    Received: ["marginTop", "marginBottom", "marginLeft", "marginRight"]
      19 |   const keys = Object.keys(style).filter((key) => !key.startsWith("transition"));
      20 |   console.log(`${property}: transitionProperty ${JSON.stringify(style.transitionProperty)}, style keys ${JSON.stringify(keys)}`);
    > 21 |   expect(keys).toEqual(expect.arrayContaining(style.transitionProperty as string[]));
         |                ^
      22 | });
      23 |
      at toEqual (src/__tests__/native/transition-key-written-elsewhere.test.tsx:21:16)
Test Suites: 1 failed, 1 total
Tests:       3 failed, 3 total
Snapshots:   0 total
Time:        1.154 s, estimated 2 s
Ran all test suites matching /src\\__tests__\\native\\transition-key-written-elsewhere.test.tsx/i.

Reproducible example repository

https://github.com/YevheniiKotyrlo/react-native-css/tree/repro/532-transition-names-a-key-the-compiler-writes-elsewhere