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prefers-contrast, prefers-reduced-transparency and inverted-colors are never measured, though AccessibilityInfo reports each #514
Description
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
The media evaluator answers prefers-color-scheme, and with #388 prefers-reduced-motion, but no other user preference, though React Native 0.86's AccessibilityInfo reports three more, each with a change event:
prefers-contrast: more:isDarkerSystemColorsEnabled()on iOS (Increase Contrast) andisHighTextContrastEnabled()on Android;prefers-reduced-transparency: reduce:isReduceTransparencyEnabled()on iOS, which Android resolvesfalse;inverted-colors: inverted:isInvertColorsEnabled()on both.
getMediaFeatureValue (src/native/conditions/media-query.ts) has no arm for them, so (prefers-contrast: more) never matches for someone who turned contrast up, and not (prefers-contrast: more) matches for everyone. With no preference set, Chromium 156, Firefox 157 and WebKit 27.2 answer prefers-contrast with no-preference; Chromium alone also answers prefers-reduced-transparency, and WebKit alone inverted-colors.
| condition | the engines that answer it | main (2421ea7) |
#426 (40bfda2) |
|---|---|---|---|
(prefers-contrast: no-preference) |
match (all three) | no match | no match |
not (prefers-contrast: more) |
match (all three) | match | no match |
(prefers-reduced-transparency: no-preference) |
match (Chromium) | no match | no match |
(inverted-colors: none) |
match (WebKit) | no match | no match |
#426 answers an unmeasured feature unknown (MQ5 §3.1), so there not (prefers-contrast: more) stops matching too, and lists these three among its known limits. Each can follow #388, which reads isReduceMotionEnabled() and reduceMotionChanged.
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 foundSteps to reproduce
- Clone the reproducer branch, which is
mainat 2421ea7 with one file added,src/__tests__/native/accessibility-preferences.test.tsx, and install:git clone --branch repro/514-accessibility-preferences-unmeasured https://github.com/YevheniiKotyrlo/react-native-css cd react-native-css yarn install - Run
yarn jest src/__tests__/native/accessibility-preferences.test.tsx.
src/__tests__/native/accessibility-preferences.test.tsx:
// With no accessibility preference set, Chromium, Firefox and WebKit answer prefers-contrast no-preference, and WebKit inverted-colors none
import { render, screen } from "@testing-library/react-native";
import { View } from "react-native-css/components/View";
import { registerCSS } from "react-native-css/jest";
test.each([
["(prefers-contrast: no-preference)", true],
["not (prefers-contrast: more)", true],
["(prefers-reduced-transparency: no-preference)", true],
["(inverted-colors: none)", true],
])("with no preference set, @media %s matches: %s", (condition, expected) => {
registerCSS(`
.child { width: 10px; }
@media ${condition} { .child { width: 37px; } }
`);
render(<View testID="child" className="child" />);
expect(screen.getByTestId("child").props.style.width === 37).toBe(expected);
});Expected: (prefers-contrast: more), (prefers-reduced-transparency: reduce) and (inverted-colors: inverted) match while AccessibilityInfo reports the setting on, and follow its change events.
Actual: none of them ever matches.
The run's output on main at 2421ea7, Windows 11, Node 26.12.1
FAIL src/__tests__/native/accessibility-preferences.test.tsx
× with no preference set, @media (prefers-contrast: no-preference) matches: true (20 ms)
√ with no preference set, @media not (prefers-contrast: more) matches: true (6 ms)
× with no preference set, @media (prefers-reduced-transparency: no-preference) matches: true (2 ms)
× with no preference set, @media (inverted-colors: none) matches: true (1 ms)
● with no preference set, @media (prefers-contrast: no-preference) matches: true
expect(received).toBe(expected) // Object.is equality
Expected: true
Received: false
15 | `);
16 | render(<View testID="child" className="child" />);
> 17 | expect(screen.getByTestId("child").props.style.width === 37).toBe(expected);
| ^
18 | });
19 |
at toBe (src/__tests__/native/accessibility-preferences.test.tsx:17:64)
● with no preference set, @media (prefers-reduced-transparency: no-preference) matches: true
expect(received).toBe(expected) // Object.is equality
Expected: true
Received: false
15 | `);
16 | render(<View testID="child" className="child" />);
> 17 | expect(screen.getByTestId("child").props.style.width === 37).toBe(expected);
| ^
18 | });
19 |
at toBe (src/__tests__/native/accessibility-preferences.test.tsx:17:64)
● with no preference set, @media (inverted-colors: none) matches: true
expect(received).toBe(expected) // Object.is equality
Expected: true
Received: false
15 | `);
16 | render(<View testID="child" className="child" />);
> 17 | expect(screen.getByTestId("child").props.style.width === 37).toBe(expected);
| ^
18 | });
19 |
at toBe (src/__tests__/native/accessibility-preferences.test.tsx:17:64)
Test Suites: 1 failed, 1 total
Tests: 3 failed, 1 passed, 4 total
Snapshots: 0 total
Time: 1.086 s, estimated 2 s
Ran all test suites matching /src\\__tests__\\native\\accessibility-preferences.test.tsx/i.
Activity