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@media (min-width: calc(50vw + 10px)) never matches: a math function in a condition is never resolved #517
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
A calc(), min(), max() or clamp() in a media or container feature stands for its value (css-values-4 §10), so on a 750px-wide screen Chromium 156, Firefox 157 and WebKit 27.2 match (min-width: calc(50vw + 10px)). One over rem already compares, since the compiler inlines rem in its first pass and lightningcss folds the rest. One over a length lightningcss cannot fold, such as vw or em, reaches parseCalcFn (src/compiler/media-query.ts), which compiles it to a sum, min, max or clamp descriptor the media and container evaluators never resolve. On main a bare vw bound never compares either; #426 resolves one against the window, and the same bound inside a math function still never matches.
| condition | Chromium, Firefox, WebKit | main (2421ea7) |
#426 (40bfda2) |
|---|---|---|---|
@media (min-width: 50vw) |
match | no match | match |
@media (min-width: calc(50vw + 10px)) |
match | no match | no match |
@media (min-width: calc(100vw + 10px)) |
no match | no match | no match |
@media not (min-width: calc(100vw + 10px)) |
match | no match | no match |
@media (min-width: min(50vw, 400px)) |
match | no match | no match |
@media (width > clamp(100px, 50vw, 800px)) |
match | no match | no match |
@container (width > calc(50vw - 100px)) |
match | no match | no match |
@container not (width > calc(50vw - 100px)) |
no match | match | no match |
#494 resolves a bare em bound and lists the same gap for an em inside calc(); #426 lists this among its known limits.
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/media-query-math.test.tsx, and install:git clone --branch repro/517-media-query-math-functions https://github.com/YevheniiKotyrlo/react-native-css cd react-native-css yarn install - Run
yarn jest src/__tests__/native/media-query-math.test.tsx.
src/__tests__/native/media-query-math.test.tsx:
// A math function in a media or container feature is its value (css-values-4 §10); a vw is one lightningcss cannot fold, and #426 resolves a bare vw in a condition against the 750x1334 jest window
import { fireEvent, render, screen } from "@testing-library/react-native";
import { View } from "react-native-css/components/View";
import { registerCSS } from "react-native-css/jest";
test.each([
["(min-width: 50vw)", true],
["(min-width: calc(50vw + 10px))", true],
["(min-width: calc(100vw + 10px))", false],
["not (min-width: calc(100vw + 10px))", true],
["(min-width: min(50vw, 400px))", true],
["(width > clamp(100px, 50vw, 800px))", true],
])("@media %s on the 750px jest window 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);
});
test.each([
["(width > calc(50vw - 100px))", true],
["not (width > calc(50vw - 100px))", false],
])("@container %s in a 400px container matches: %s", (condition, expected) => {
registerCSS(`
.parent { container-type: size; }
.child { width: 10px; }
@container ${condition} { .child { width: 37px; } }
`);
render(
<View testID="parent" className="parent">
<View testID="child" className="child" />
</View>,
);
fireEvent(screen.getByTestId("parent"), "layout", {
nativeEvent: { layout: { x: 0, y: 0, width: 400, height: 200 } },
});
expect(screen.getByTestId("child").props.style.width === 37).toBe(expected);
});Expected: (min-width: calc(50vw + 10px)) matches on a screen wide enough for it, as in a browser.
Actual: the condition never matches.
The run's output on main at 2421ea7, Windows 11, Node 26.12.1
FAIL src/__tests__/native/media-query-math.test.tsx
× @media (min-width: 50vw) on the 750px jest window matches: true (18 ms)
× @media (min-width: calc(50vw + 10px)) on the 750px jest window matches: true (6 ms)
√ @media (min-width: calc(100vw + 10px)) on the 750px jest window matches: false (1 ms)
× @media not (min-width: calc(100vw + 10px)) on the 750px jest window matches: true (2 ms)
× @media (min-width: min(50vw, 400px)) on the 750px jest window matches: true (1 ms)
× @media (width > clamp(100px, 50vw, 800px)) on the 750px jest window matches: true (1 ms)
× @container (width > calc(50vw - 100px)) in a 400px container matches: true (6 ms)
× @container not (width > calc(50vw - 100px)) in a 400px container matches: false (1 ms)
● @media (min-width: 50vw) on the 750px jest window matches: true
expect(received).toBe(expected) // Object.is equality
Expected: true
Received: false
17 | `);
18 | render(<View testID="child" className="child" />);
> 19 | expect(screen.getByTestId("child").props.style.width === 37).toBe(expected);
| ^
20 | });
21 |
22 | test.each([
at toBe (src/__tests__/native/media-query-math.test.tsx:19:64)
● @media (min-width: calc(50vw + 10px)) on the 750px jest window matches: true
expect(received).toBe(expected) // Object.is equality
Expected: true
Received: false
17 | `);
18 | render(<View testID="child" className="child" />);
> 19 | expect(screen.getByTestId("child").props.style.width === 37).toBe(expected);
| ^
20 | });
21 |
22 | test.each([
at toBe (src/__tests__/native/media-query-math.test.tsx:19:64)
● @media not (min-width: calc(100vw + 10px)) on the 750px jest window matches: true
expect(received).toBe(expected) // Object.is equality
Expected: true
Received: false
17 | `);
18 | render(<View testID="child" className="child" />);
> 19 | expect(screen.getByTestId("child").props.style.width === 37).toBe(expected);
| ^
20 | });
21 |
22 | test.each([
at toBe (src/__tests__/native/media-query-math.test.tsx:19:64)
● @media (min-width: min(50vw, 400px)) on the 750px jest window matches: true
expect(received).toBe(expected) // Object.is equality
Expected: true
Received: false
17 | `);
18 | render(<View testID="child" className="child" />);
> 19 | expect(screen.getByTestId("child").props.style.width === 37).toBe(expected);
| ^
20 | });
21 |
22 | test.each([
at toBe (src/__tests__/native/media-query-math.test.tsx:19:64)
● @media (width > clamp(100px, 50vw, 800px)) on the 750px jest window matches: true
expect(received).toBe(expected) // Object.is equality
Expected: true
Received: false
17 | `);
18 | render(<View testID="child" className="child" />);
> 19 | expect(screen.getByTestId("child").props.style.width === 37).toBe(expected);
| ^
20 | });
21 |
22 | test.each([
at toBe (src/__tests__/native/media-query-math.test.tsx:19:64)
● @container (width > calc(50vw - 100px)) in a 400px container matches: true
expect(received).toBe(expected) // Object.is equality
Expected: true
Received: false
37 | nativeEvent: { layout: { x: 0, y: 0, width: 400, height: 200 } },
38 | });
> 39 | expect(screen.getByTestId("child").props.style.width === 37).toBe(expected);
| ^
40 | });
41 |
at toBe (src/__tests__/native/media-query-math.test.tsx:39:64)
● @container not (width > calc(50vw - 100px)) in a 400px container matches: false
expect(received).toBe(expected) // Object.is equality
Expected: false
Received: true
37 | nativeEvent: { layout: { x: 0, y: 0, width: 400, height: 200 } },
38 | });
> 39 | expect(screen.getByTestId("child").props.style.width === 37).toBe(expected);
| ^
40 | });
41 |
at toBe (src/__tests__/native/media-query-math.test.tsx:39:64)
Test Suites: 1 failed, 1 total
Tests: 7 failed, 1 passed, 8 total
Snapshots: 0 total
Time: 1.062 s, estimated 2 s
Ran all test suites matching /src\\__tests__\\native\\media-query-math.test.tsx/i.
Reproducible example repository
https://github.com/YevheniiKotyrlo/react-native-css/tree/repro/517-media-query-math-functions
Activity