`@media (min-width: calc(50vw + 10px))` never matches: a math function in a condition is never resolved

Abierto

#517 abierto el 29/10/2026 0 comentarios 0 reacciones 0 asignados Ver en GitHub

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Nadie ha tomado este issue todavía.

Evaluación

Dificultad: 4/5
Tiempo estimado: 3-5 días
Aptitud para principiantes: 56/100

Tipo de issue: Error
Claridad: Bien especificado
Estado de actividad: Activo
Stack tecnológico: javascript, react-native, typescript
Área: frontend, testing

Línea de trabajo

Start with src/compiler/media-query.ts and the media and container evaluators named in the report; read how parseCalcFn produces descriptors and compare that with the existing bare vw handling from #426. Run the provided media-query-math.test.tsx reproducer, then check the full media and container condition coverage. Done means the reported math functions resolve correctly for media and container conditions, including negated conditions.

Escrito por el modelo de indexación a partir del texto del issue.

Descripción

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 found

Steps to reproduce

Clone the reproducer branch, which is main at 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

Lenguaje dominante: TypeScript
Estrellas: 166
Forks: 45
Merge medio: 13 d 14 h
PR fusionados (30 d): 1

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Más issues de TypeScript

`@media (min-width: calc(50vw + 10px))` never matches: a math function in a condition is never resolved

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Evaluación

Línea de trabajo

Descripción

Before submitting a new issue

Bug summary

Library version

Environment info

Steps to reproduce

Reproducible example repository

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Primeros pasos

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