Extract CSS vars from RAC docs into reusable package

.parcelrc

@@ -9,7 +9,7 @@
     "bundle-text:*.svg": ["@parcel/transformer-svg", "@parcel/transformer-inline-string"],
     "*.{md,mdx}": ["parcel-transformer-mdx-docs"],
     "*.svg": ["@parcel/transformer-svg-react"],
-    "*.global.css": ["parcel-transformer-css-global", "..."],
+    "packages/@react-aria/example-theme/**/*.css": ["@parcel/transformer-css"],
     "*.css": ["...", "parcel-transformer-css-env"],
     "*.{js,mjs,jsm,jsx,es6,cjs,ts,tsx}": [
       "@parcel/transformer-js",

package.json

@@ -187,7 +187,10 @@
     "browserslist": "4.20.3"
   },
   "@parcel/transformer-css": {
-    "cssModules": true,
+    "cssModules": {
+      "global": true,
+      "exclude": ["**/*.global.css", "packages/@react-aria/example-theme/**"]
+    },
     "drafts": {
       "nesting": true
     },

packages/@react-aria/example-theme/README.md

@@ -0,0 +1,3 @@
+# @react-aria/example-theme
+
+This package is part of [react-spectrum](https://github.com/adobe/react-spectrum). See the repo for more details.

packages/@react-aria/example-theme/package.json

@@ -0,0 +1,22 @@
+{
+  "name": "@react-aria/example-theme",
+  "version": "1.0.0",
+  "description": "Spectrum UI components in React",
+  "license": "Apache-2.0",
+  "source": "src/index.css",
+  "dist": "dist/index.css",
+  "main": "dist/index.css",
+  "targets": {
+    "main": false,
+    "dist": {
+      "optimize": false
+    }
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/adobe/react-spectrum"
+  },
+  "publishConfig": {
+    "access": "public"
+  }
+}

packages/@react-aria/example-theme/src/index.css

@@ -0,0 +1,118 @@
+/* color themes for dark and light modes, generated with Leonardo.
+ * Light: https://leonardocolor.io/theme.html?name=Light&config=%7B%22baseScale%22%3A%22Gray%22%2C%22colorScales%22%3A%5B%7B%22name%22%3A%22Gray%22%2C%22colorKeys%22%3A%5B%22%23000000%22%5D%2C%22colorspace%22%3A%22RGB%22%2C%22ratios%22%3A%5B%22-1.12%22%2C%221.45%22%2C%222.05%22%2C%223.02%22%2C%224.54%22%2C%227%22%2C%2210.86%22%5D%2C%22smooth%22%3Afalse%7D%2C%7B%22name%22%3A%22Purple%22%2C%22colorKeys%22%3A%5B%22%235e30eb%22%5D%2C%22colorspace%22%3A%22RGB%22%2C%22ratios%22%3A%5B%22-1.12%22%2C%221.45%22%2C%222.05%22%2C%223.02%22%2C%224.54%22%2C%227%22%2C%2210.86%22%5D%2C%22smooth%22%3Afalse%7D%2C%7B%22name%22%3A%22Red%22%2C%22colorKeys%22%3A%5B%22%23e32400%22%5D%2C%22colorspace%22%3A%22RGB%22%2C%22ratios%22%3A%5B%22-1.12%22%2C%221.45%22%2C%222.05%22%2C%223.02%22%2C%224.54%22%2C%227%22%2C%2210.86%22%5D%2C%22smooth%22%3Afalse%7D%5D%2C%22lightness%22%3A98%2C%22contrast%22%3A1%2C%22saturation%22%3A100%2C%22formula%22%3A%22wcag2%22%7D */
+:root {
+  --background-color: #f8f8f8;
+  --gray-50: #ffffff;
+  --gray-100: #d0d0d0;
+  --gray-200: #afafaf;
+  --gray-300: #8f8f8f;
+  --gray-400: #717171;
+  --gray-500: #555555;
+  --gray-600: #393939;
+  --purple-100: #d5c9fa;
+  --purple-200: #b8a3f6;
+  --purple-300: #997cf2;
+  --purple-400: #7a54ef;
+  --purple-500: #582ddc;
+  --purple-600: #3c1e95;
+  --red-100: #f7c4ba;
+  --red-200: #f29887;
+  --red-300: #eb664d;
+  --red-400: #de2300;
+  --red-500: #a81b00;
+  --red-600: #731200;
+  --highlight-hover: rgb(0 0 0 / 0.07);
+  --highlight-pressed: rgb(0 0 0 / 0.15);
+}
+
+/* Dark: https://leonardocolor.io/theme.html?name=Dark&config=%7B%22baseScale%22%3A%22Gray%22%2C%22colorScales%22%3A%5B%7B%22name%22%3A%22Gray%22%2C%22colorKeys%22%3A%5B%22%23000000%22%5D%2C%22colorspace%22%3A%22RGB%22%2C%22ratios%22%3A%5B%22-1.12%22%2C%221.45%22%2C%222.05%22%2C%223.02%22%2C%224.54%22%2C%227%22%2C%2210.86%22%5D%2C%22smooth%22%3Afalse%7D%2C%7B%22name%22%3A%22Purple%22%2C%22colorKeys%22%3A%5B%22%235e30eb%22%5D%2C%22colorspace%22%3A%22RGB%22%2C%22ratios%22%3A%5B%22-1.12%22%2C%221.45%22%2C%222.05%22%2C%223.02%22%2C%224.54%22%2C%227%22%2C%2210.86%22%5D%2C%22smooth%22%3Afalse%7D%2C%7B%22name%22%3A%22Red%22%2C%22colorKeys%22%3A%5B%22%23e32400%22%5D%2C%22colorspace%22%3A%22RGB%22%2C%22ratios%22%3A%5B%22-1.12%22%2C%221.45%22%2C%222.05%22%2C%223.02%22%2C%224.54%22%2C%227%22%2C%2210.86%22%5D%2C%22smooth%22%3Afalse%7D%5D%2C%22lightness%22%3A11%2C%22contrast%22%3A1%2C%22saturation%22%3A100%2C%22formula%22%3A%22wcag2%22%7D */
+@media (prefers-color-scheme: dark) {
+  :root {
+    --background-color: #1d1d1d;
+    --gray-50: #101010;
+    --gray-100: #393939;
+    --gray-200: #4f4f4f;
+    --gray-300: #686868;
+    --gray-400: #848484;
+    --gray-500: #a7a7a7;
+    --gray-600: #cfcfcf;
+    --purple-100: #3c1e95;
+    --purple-200: #522acd;
+    --purple-300: #6f46ed;
+    --purple-400: #8e6ef1;
+    --purple-500: #b099f5;
+    --purple-600: #d5c8fa;
+    --red-100: #721200;
+    --red-200: #9c1900;
+    --red-300: #cc2000;
+    --red-400: #e95034;
+    --red-500: #f08c79;
+    --red-600: #f7c3ba;
+    --highlight-hover: rgb(255 255 255 / 0.1);
+    --highlight-pressed: rgb(255 255 255 / 0.2);
+  }
+}
+
+/* Semantic colors */
+:root {
+  --focus-ring-color: var(--purple-400);
+  --text-color: var(--gray-600);
+  --text-color-base: var(--gray-500);
+  --text-color-hover: var(--gray-600);
+  --text-color-disabled: var(--gray-200);
+  --text-color-placeholder: var(--gray-400);
+  --link-color: var(--purple-500);
+  --link-color-secondary: var(--gray-500);
+  --link-color-pressed: var(--purple-600);
+  --border-color: var(--gray-300);
+  --border-color-hover: var(--gray-400);
+  --border-color-pressed: var(--gray-400);
+  --border-color-disabled: var(--gray-100);
+  --field-background: var(--gray-50);
+  --field-text-color: var(--gray-600);
+  --overlay-background: var(--gray-50);
+  --button-background: var(--gray-50);
+  --button-background-pressed: var(--background-color);
+  /* these colors are the same between light and dark themes
+   * to ensure contrast with the foreground color */
+  --highlight-background: #6f46ed; /* purple-300 from dark theme, 3.03:1 against background-color */
+  --highlight-background-pressed: #522acd; /* purple-200 from dark theme */
+  --highlight-background-invalid: #cc2000; /* red-300 from dark theme */
+  --highlight-foreground: white; /* 5.56:1 against highlight-background */
+  --highlight-foreground-pressed: #ddd;
+  --highlight-overlay: rgb(from #6f46ed r g b / 15%);
+  --invalid-color: var(--red-400);
+  --invalid-color-pressed: var(--red-500);
+}
+
+/* Windows high contrast mode overrides */
+@media (forced-colors: active) {
+  :root {
+    --background-color: Canvas;
+    --focus-ring-color: Highlight;
+    --text-color: ButtonText;
+    --text-color-base: ButtonText;
+    --text-color-hover: ButtonText;
+    --text-color-disabled: GrayText;
+    --text-color-placeholder: ButtonText;
+    --link-color: LinkText;
+    --link-color-secondary: LinkText;
+    --link-color-pressed: LinkText;
+    --border-color: ButtonBorder;
+    --border-color-hover: ButtonBorder;
+    --border-color-pressed: ButtonBorder;
+    --border-color-disabled: GrayText;
+    --field-background: Field;
+    --field-text-color: FieldText;
+    --overlay-background: Canvas;
+    --button-background: ButtonFace;
+    --button-background-pressed: ButtonFace;
+    --highlight-background: Highlight;
+    --highlight-background-pressed: Highlight;
+    --highlight-background-invalid: LinkText;
+    --highlight-foreground: HighlightText;
+    --highlight-foreground-pressed: HighlightText;
+    --invalid-color: LinkText;
+    --invalid-color-pressed: LinkText;
+  }
+}

packages/dev/parcel-transformer-mdx-docs/MDXTransformer.js

@@ -17,9 +17,7 @@ const {fragmentUnWrap, fragmentWrap} = require('./MDXFragments');
 const yaml = require('js-yaml');
 const dprint = require('dprint-node');
 const t = require('@babel/types');
-const lightningcss = require('lightningcss');
-const fs = require('fs');
-const path = require('path');
+const processCSS = require('./processCSS');
 
 const IMPORT_MAPPINGS = {
   '@react-spectrum/theme-default': {
@@ -44,9 +42,6 @@ module.exports = new Transformer({
     let preRelease = preReleaseParts ? preReleaseParts[0] : '';
 
     let visit = (await import('unist-util-visit')).visit;
-    let unified = (await import('unified')).unified;
-    let remarkParse = (await import('remark-parse')).default;
-    let remarkMdx = (await import('remark-mdx')).default;
     const extractExamples = () => (tree, file) => (
       flatMap(tree, node => {
         if (node.type === 'code') {
@@ -169,50 +164,7 @@ module.exports = new Transformer({
     );
 
     let appendCSS = () => async (tree) => {
-      let transformed = await lightningcss.bundleAsync({
-        filename: `${asset.filePath}.lightning`,
-        minify: true,
-        drafts: {
-          nesting: true
-        },
-        targets: {
-          chrome: 95 << 16,
-          safari: 15 << 16
-        },
-        resolver: {
-          resolve(specifier, parent) {
-            if (specifier.startsWith('.')) {
-              return path.resolve(path.dirname(parent), specifier);
-            }
-
-            let baseDir = process.env.DOCS_ENV === 'production' ? 'docs' : 'packages';
-            return path.resolve(options.projectRoot, baseDir, specifier);
-          },
-          read(filePath) {
-            if (filePath === `${asset.filePath}.lightning`) {
-              return cssCode.join('\n');
-            }
-            let result = '';
-            try {
-              let contents = fs.readFileSync(filePath, 'utf8');
-              // get all css blocks and concat
-              let ast = unified().use(remarkParse).use(remarkMdx).parse(contents);
-              visit(ast, 'code', node => {
-                if (node.lang !== 'css' || node?.meta?.includes('render=false') || node?.meta?.includes('hidden')) {
-                  return;
-                }
-                let code = node.value;
-                code = code.replace(/@import.*/g, '');
-                result += code;
-              });
-            } catch (e) {
-              console.log(e);
-            }
-            return result;
-          }
-        }
-      });
-      let css = transformed.code.toString();
+      let css = await processCSS(cssCode, asset, options);
 
       tree.children.push(
         {

packages/dev/parcel-transformer-mdx-docs/processCSS.js

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2020 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+const lightningcss = require('lightningcss');
+const fs = require('fs');
+const path = require('path');
+
+module.exports = async function processCSS(cssCode, asset, options) {
+  let visit = (await import('unist-util-visit')).visit;
+  let unified = (await import('unified')).unified;
+  let remarkParse = (await import('remark-parse')).default;
+  let remarkMdx = (await import('remark-mdx')).default;
+  let transformed = await lightningcss.bundleAsync({
+    filename: `${asset.filePath}.lightning`,
+    minify: true,
+    drafts: {
+      nesting: true
+    },
+    targets: {
+      chrome: 95 << 16,
+      safari: 15 << 16
+    },
+    resolver: {
+      resolve(specifier, parent) {
+        if (specifier.startsWith('.')) {
+          return path.resolve(path.dirname(parent), specifier);
+        }
+
+        if (path.extname(specifier) === '') {
+          // Assume this is a package.
+          specifier += '/src/index.css';
+        }
+
+        let baseDir = process.env.DOCS_ENV === 'production' ? 'docs' : 'packages';
+        return path.resolve(options.projectRoot, baseDir, specifier);
+      },
+      read(filePath) {
+        if (filePath === `${asset.filePath}.lightning`) {
+          return cssCode.join('\n');
+        }
+        asset.invalidateOnFileChange(filePath);
+
+        let result = '';
+        try {
+          let contents = fs.readFileSync(filePath, 'utf8');
+          if (path.extname(filePath) === '.css') {
+            return contents;
+          }
+          // get all css blocks and concat
+          let ast = unified().use(remarkParse).use(remarkMdx).parse(contents);
+          visit(ast, 'code', node => {
+            if (node.lang !== 'css' || node?.meta?.includes('render=false') || node?.meta?.includes('hidden')) {
+              return;
+            }
+            let code = node.value;
+            code = code.replace(/@import.*/g, '');
+            result += code;
+          });
+        } catch (e) {
+          console.log(e);
+        }
+        return result;
+      }
+    },
+    visitor: {
+      Rule: {
+        media(m) {
+          // Convert dark mode media query to use docs color scheme.
+          let mediaQueries = m.value.query.mediaQueries;
+          let condition = mediaQueries[0].condition;
+          let isDarkMode = mediaQueries.length === 1
+            && condition.type === 'feature'
+            && condition.value.type === 'plain'
+            && condition.value.name === 'prefers-color-scheme'
+            && condition.value.value.value === 'dark';
+          if (isDarkMode) {
+            return {
+              type: 'style',
+              value: {
+                // Generates this selector: `:root[style*="color-scheme: dark"]`
+                selectors: [[
+                  {type: 'pseudo-class', kind: 'root'},
+                  {type: 'attribute', name: 'style', operation: {operator: 'substring', value: 'color-scheme: dark'}}
+                ]],
+                loc: m.value.loc,
+                declarations: m.value.rules[0].value.declarations
+              }
+            };
+          }
+        }
+      }
+    }
+  });
+
+  return transformed.code.toString();
+};