Add Tailwind support to Astro Dev Server (#222)

* Improve PostCSS and Tailwind support

* Update styling docs

* Changelog

* Fix test hanging

.changeset/red-eyes-stare.md

@@ -0,0 +1,5 @@
+---
+'astro': minor
+---
+
+Add Tailwind JIT support for Astro

docs/config.md

@@ -28,6 +28,8 @@ export default {
   devOptions: {
     /** The port to run the dev server on. */
     port: 3000,
+    /** Path to tailwind.config.js if used, e.g. './tailwind.config.js' */
+    tailwindConfig: undefined,
   },
 };
 ```

docs/styling.md

@@ -4,13 +4,15 @@ Styling in Astro is meant to be as flexible as you’d like it to be! The follow
 
 | Framework        | Global CSS | Scoped CSS | CSS Modules |
 | :--------------- | :--------: | :--------: | :---------: |
-| Astro (`.astro`) |     ✅     |     ✅     |    N/A¹     |
-| React / Preact   |     ✅     |     ❌     |     ✅      |
-| Vue              |     ✅     |     ✅     |     ✅      |
-| Svelte           |     ✅     |     ✅     |     ❌      |
+| `.astro`         |     ✅     |     ✅     |    N/A¹     |
+| `.jsx` \| `.tsx` |     ✅     |     ❌     |     ✅      |
+| `.vue`           |     ✅     |     ✅     |     ✅      |
+| `.svelte`        |     ✅     |     ✅     |     ❌      |
 
 ¹ _`.astro` files have no runtime, therefore Scoped CSS takes the place of CSS Modules (styles are still scoped to components, but don’t need dynamic values)_
 
+All styles in Astro are automatically [**autoprefixed**](#-autoprefixer) and optimized, so you can just write CSS and we’ll handle the rest ✨.
+
 ## 🖍 Quick Start
 
 ##### Astro
@@ -92,7 +94,6 @@ And also create a `tailwind.config.js` in your project root:
 
 ```js
 // tailwind.config.js
-
 module.exports = {
   mode: 'jit',
   purge: ['./public/**/*.html', './src/**/*.{astro,js,jsx,ts,tsx,vue}'],
@@ -100,19 +101,36 @@ module.exports = {
 };
 ```
 
-Then add [Tailwind utilities][tailwind-utilities] to any Astro component that needs it:
+Be sure to add the config path to `astro.config.mjs`, so that Astro enables JIT support in the dev server.
 
-```html
-<style>
-  @tailwind base;
-  @tailwind components;
-  @tailwind utilities;
-</style>
+```diff
+  // astro.config.mjs
+  export default {
++   devOptions: {
++     tailwindConfig: './tailwindConfig.js',
++   },
+  };
 ```
 
-You should see Tailwind styles compile successfully in Astro.
+Now you’re ready to write Tailwind! Our recommended approach is to create a `public/global.css` file with [Tailwind utilities][tailwind-utilities] like so:
 
-💁 **Tip**: to reduce duplication, try loading `@tailwind base` from a parent page (`./pages/*.astro`) instead of the component itself.
+```css
+/* public/global.css */
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+```
+
+💁 As an alternative to `public/global.css`, You may also add Tailwind utilities to individual `pages/*.astro` components in `<style>` tags, but be mindful of duplication! If you end up creating multiple Tailwind-managed stylesheets for your site, make sure you’re not sending the same CSS to users over and over again in separate CSS files.
+
+#### 📦 Bundling
+
+All CSS is minified and bundled automatically for you in running `astro build`. The general specifics are:
+
+- If a style only appears on one route, it’s only loaded for that route
+- If a style appears on multiple routes, it’s deduplicated into a `common.css` bundle
+
+We’ll be expanding our styling optimization story over time, and would love your feedback! If `astro build` generates unexpected styles, or if you can think of improvements, [please open an issue](https://github.com/snowpackjs/astro/issues).
 
 ## 📚 Advanced Styling Architecture in Astro
 

examples/snowpack/.stylelintrc.js

@@ -1,15 +0,0 @@
-module.exports = {
-  extends: [
-    'stylelint-config-standard',
-    'stylelint-config-rational-order',
-    'stylelint-config-prettier',
-  ],
-  rules: {
-    'at-rule-no-unknown': [
-      true,
-      { ignoreAtRules: ['use', 'each', 'for', 'mixin', 'extend', 'include'] },
-    ], // allow Sass syntax,
-    'no-descending-specificity': null,
-  },
-  syntax: 'scss',
-};

examples/snowpack/package.json

@@ -8,7 +8,6 @@
     "astro-dev": "nodemon --delay 0.5 -w ../../packages/astro/dist -x '../../packages/astro/astro.mjs dev'",
     "test": "jest /__test__/",
     "format": "prettier --write \"src/**/*.js\" && yarn format:css",
-    "format:css": "stylelint 'src/**/*.scss' --fix",
     "lint": "prettier --check \"src/**/*.js\""
   },
   "dependencies": {
@@ -31,11 +30,7 @@
     "luxon": "^1.25.0",
     "markdown-it": "^12.0.2",
     "markdown-it-anchor": "^6.0.0",
-    "nodemon": "^2.0.7",
-    "stylelint": "^13.8.0",
-    "stylelint-config-prettier": "^8.0.2",
-    "stylelint-config-rational-order": "^0.1.2",
-    "stylelint-config-standard": "^20.0.0"
+    "nodemon": "^2.0.7"
   },
   "snowpack": {
     "workspaceRoot": "../.."

examples/tailwindcss/astro.config.mjs

@@ -0,0 +1,5 @@
+export default {
+  devOptions: {
+    tailwindConfig: './tailwind.config.js',
+  },
+};

examples/tailwindcss/package.json

@@ -9,7 +9,7 @@
   },
   "devDependencies": {
     "astro": "^0.10.0",
-    "tailwindcss": "^2.1.1"
+    "tailwindcss": "^2.1.2"
   },
   "snowpack": {
     "workspaceRoot": "../.."

examples/tailwindcss/public/global.css

@@ -0,0 +1,3 @@
+@tailwind base;
+@tailwind components;
+@tailwind utilities;

examples/tailwindcss/src/components/Button.astro

@@ -1,8 +1,3 @@
-<style>
-  @tailwind components;
-  @tailwind utilities;
-</style>
-
 <button class="py-2 px-4 bg-green-500 text-white font-semibold rounded-lg shadow-md hover:bg-green-700 focus:outline-none focus:ring-2 focus:ring-green-400 focus:ring-opacity-75">
   <slot />
 </button>

examples/tailwindcss/src/pages/index.astro

@@ -6,9 +6,7 @@ import Button from '../components/Button.astro';
   <head>
     <meta charset="UTF-8" />
     <title>Astro + TailwindCSS</title>
-    <style>
-      @tailwind base;
-    </style>
+    <link rel="stylesheet" type="text/css" href="/global.css">
   </head>
 
   <body>

packages/astro/package.json

@@ -36,9 +36,10 @@
     "@babel/parser": "^7.13.15",
     "@babel/traverse": "^7.13.15",
     "@silvenon/remark-smartypants": "^1.0.0",
+    "@snowpack/plugin-postcss": "^1.4.0",
     "@snowpack/plugin-sass": "^1.4.0",
-    "@snowpack/plugin-svelte": "^3.6.1",
-    "@snowpack/plugin-vue": "^2.4.0",
+    "@snowpack/plugin-svelte": "^3.7.0",
+    "@snowpack/plugin-vue": "^2.5.0",
     "@vue/server-renderer": "^3.0.10",
     "acorn": "^7.4.0",
     "astro-parser": "0.1.0",
@@ -64,7 +65,7 @@
     "moize": "^6.0.1",
     "node-fetch": "^2.6.1",
     "picomatch": "^2.2.3",
-    "postcss": "^8.2.8",
+    "postcss": "^8.2.15",
     "postcss-icss-keyframes": "^0.2.1",
     "preact": "^10.5.13",
     "preact-render-to-string": "^5.1.18",
@@ -83,7 +84,7 @@
     "sass": "^1.32.13",
     "shorthash": "^0.0.2",
     "slash": "^4.0.0",
-    "snowpack": "^3.3.7",
+    "snowpack": "^3.5.1",
     "source-map-support": "^0.5.19",
     "string-width": "^5.0.0",
     "svelte": "^3.35.0",

packages/astro/src/@types/astro.ts

@@ -26,6 +26,8 @@ export interface AstroConfig {
     /** The port to run the dev server on. */
     port: number;
     projectRoot?: string;
+    /** Path to tailwind.config.js, if used */
+    tailwindConfig?: string;
   };
 }
 
@@ -36,6 +38,7 @@ export type AstroUserConfig = Omit<AstroConfig, 'buildOptions' | 'devOptions'> &
   devOptions: {
     port?: number;
     projectRoot?: string;
+    tailwindConfig?: string;
   };
 };
 

packages/astro/src/@types/compiler.ts

@@ -7,4 +7,5 @@ export interface CompileOptions {
   astroConfig: AstroConfig;
   extensions?: Record<string, ValidExtensionPlugins>;
   mode: RuntimeMode;
+  tailwindConfig?: string;
 }

packages/astro/src/compiler/transform/styles.ts

@@ -2,7 +2,6 @@ import type { TransformOptions, Transformer } from '../../@types/transformer';
 import type { TemplateNode } from 'astro-parser';
 
 import crypto from 'crypto';
-import fs from 'fs';
 import { createRequire } from 'module';
 import path from 'path';
 import { fileURLToPath } from 'url';
@@ -55,7 +54,6 @@ export interface StyleTransformResult {
 
 interface StylesMiniCache {
   nodeModules: Map<string, string>; // filename: node_modules location
-  tailwindEnabled?: boolean; // cache once per-run
 }
 
 /** Simple cache that only exists in memory per-run. Prevents the same lookups from happening over and over again within the same build or dev server session. */
@@ -68,6 +66,7 @@ export interface TransformStyleOptions {
   type?: string;
   filename: string;
   scopedClass: string;
+  tailwindConfig?: string;
 }
 
 /** given a class="" string, does it contain a given class? */
@@ -80,7 +79,7 @@ function hasClass(classList: string, className: string): boolean {
 }
 
 /** Convert styles to scoped CSS */
-async function transformStyle(code: string, { logging, type, filename, scopedClass }: TransformStyleOptions): Promise<StyleTransformResult> {
+async function transformStyle(code: string, { logging, type, filename, scopedClass, tailwindConfig }: TransformStyleOptions): Promise<StyleTransformResult> {
   let styleType: StyleType = 'css'; // important: assume CSS as default
   if (type) {
     styleType = getStyleType.get(type) || styleType;
@@ -122,7 +121,7 @@ async function transformStyle(code: string, { logging, type, filename, scopedCla
   const postcssPlugins: Plugin[] = [];
 
   // 2a. Tailwind (only if project uses Tailwind)
-  if (miniCache.tailwindEnabled) {
+  if (tailwindConfig) {
     try {
       const require = createRequire(import.meta.url);
       const tw = require.resolve('tailwindcss', { paths: [import.meta.url, process.cwd()] });
@@ -192,21 +191,6 @@ export default function transformStyles({ compileOptions, filename, fileID }: Tr
   const styleTransformPromises: Promise<StyleTransformResult>[] = []; // async style transform results to be finished in finalize();
   const scopedClass = `astro-${hashFromFilename(fileID)}`; // this *should* generate same hash from fileID every time
 
-  // find Tailwind config, if first run (cache for subsequent runs)
-  if (miniCache.tailwindEnabled === undefined) {
-    const tailwindNames = ['tailwind.config.js', 'tailwind.config.mjs'];
-    for (const loc of tailwindNames) {
-      const tailwindLoc = path.join(fileURLToPath(compileOptions.astroConfig.projectRoot), loc);
-      if (fs.existsSync(tailwindLoc)) {
-        miniCache.tailwindEnabled = true; // Success! We have a Tailwind config file.
-        debug(compileOptions.logging, 'tailwind', 'Found config. Enabling.');
-        break;
-      }
-    }
-    if (miniCache.tailwindEnabled !== true) miniCache.tailwindEnabled = false; // We couldn‘t find one; mark as false
-    debug(compileOptions.logging, 'tailwind', 'No config found. Skipping.');
-  }
-
   return {
     visitors: {
       html: {
@@ -231,6 +215,7 @@ export default function transformStyles({ compileOptions, filename, fileID }: Tr
                   type: (langAttr && langAttr.value[0] && langAttr.value[0].data) || undefined,
                   filename,
                   scopedClass,
+                  tailwindConfig: compileOptions.tailwindConfig,
                 })
               );
               return;

packages/astro/src/config.ts

@@ -28,12 +28,15 @@ function validateConfig(config: any): void {
   }
 
   // buildOptions
-  if (config.buildOptions && config.buildOptions.site !== undefined) {
-    if (typeof config.buildOptions.site !== 'string') throw new Error(`[config] buildOptions.site is not a string`);
-    try {
-      new URL(config.buildOptions.site);
-    } catch (err) {
-      throw new Error('[config] buildOptions.site must be a valid URL');
+  if (config.buildOptions) {
+    // buildOptions.site
+    if (config.buildOptions.site !== undefined) {
+      if (typeof config.buildOptions.site !== 'string') throw new Error(`[config] buildOptions.site is not a string`);
+      try {
+        new URL(config.buildOptions.site);
+      } catch (err) {
+        throw new Error('[config] buildOptions.site must be a valid URL');
+      }
     }
   }
 
@@ -41,6 +44,9 @@ function validateConfig(config: any): void {
   if (typeof config.devOptions?.port !== 'number') {
     throw new Error(`[config] devOptions.port: Expected number, received ${type(config.devOptions?.port)}`);
   }
+  if (config.devOptions?.tailwindConfig !== undefined && typeof config.devOptions?.tailwindConfig !== 'string') {
+    throw new Error(`[config] devOptions.tailwindConfig: Expected string, received ${type(config.devOptions?.tailwindConfig)}`);
+  }
 }
 
 /** Set default config values */

packages/astro/src/dev.ts

@@ -47,7 +47,7 @@ export default async function dev(astroConfig: AstroConfig) {
         break;
       }
       case 404: {
-        const fullurl = new URL(req.url || '/', 'https://example.org/');
+        const fullurl = new URL(req.url || '/', astroConfig.buildOptions.site || `http://localhost${astroConfig.devOptions.port}`);
         const reqPath = decodeURI(fullurl.pathname);
         error(logging, 'static', 'Not found', reqPath);
         res.statusCode = 404;

packages/astro/src/runtime.ts

@@ -266,12 +266,13 @@ interface CreateSnowpackOptions {
   env: Record<string, any>;
   mode: RuntimeMode;
   resolvePackageUrl?: (pkgName: string) => Promise<string>;
+  target: 'frontend' | 'backend';
 }
 
 /** Create a new Snowpack instance to power Astro */
 async function createSnowpack(astroConfig: AstroConfig, options: CreateSnowpackOptions) {
   const { projectRoot, astroRoot, extensions } = astroConfig;
-  const { env, mode, resolvePackageUrl } = options;
+  const { env, mode, resolvePackageUrl, target } = options;
 
   const internalPath = new URL('./frontend/', import.meta.url);
 
@@ -295,20 +296,43 @@ async function createSnowpack(astroConfig: AstroConfig, options: CreateSnowpackO
     mountOptions[fileURLToPath(astroConfig.public)] = '/';
   }
 
+  const plugins: (string | [string, any])[] = [
+    [fileURLToPath(new URL('../snowpack-plugin.cjs', import.meta.url)), astroPlugOptions],
+    [require.resolve('@snowpack/plugin-svelte'), { compilerOptions: { hydratable: true } }],
+    require.resolve('@snowpack/plugin-vue'),
+  ];
+
+  // note: styles only need processing once
+  if (target === 'frontend') {
+    plugins.push(require.resolve('@snowpack/plugin-sass'));
+    plugins.push([
+      require.resolve('@snowpack/plugin-postcss'),
+      {
+        config: {
+          plugins: {
+            [require.resolve('autoprefixer')]: {},
+            ...(astroConfig.devOptions.tailwindConfig ? { [require.resolve('tailwindcss')]: {} } : {}),
+          },
+        },
+      },
+    ]);
+  }
+
+  // Tailwind: IDK what this does but it makes JIT work 🤷‍♂️
+  if (astroConfig.devOptions.tailwindConfig) {
+    (process.env as any).TAILWIND_DISABLE_TOUCH = true;
+  }
+
   const snowpackConfig = await loadConfiguration({
     root: fileURLToPath(projectRoot),
     mount: mountOptions,
     mode,
-    plugins: [
-      [fileURLToPath(new URL('../snowpack-plugin.cjs', import.meta.url)), astroPlugOptions],
-      require.resolve('@snowpack/plugin-sass'),
-      [require.resolve('@snowpack/plugin-svelte'), { compilerOptions: { hydratable: true } }],
-      require.resolve('@snowpack/plugin-vue'),
-    ],
+    plugins,
     devOptions: {
       open: 'none',
       output: 'stream',
       port: 0,
+      tailwindConfig: astroConfig.devOptions.tailwindConfig,
     },
     buildOptions: {
       out: astroConfig.dist,
@@ -343,6 +367,7 @@ export async function createRuntime(astroConfig: AstroConfig, { mode, logging }:
     },
     mode,
     resolvePackageUrl,
+    target: 'backend',
   });
   debug(logging, 'core', `backend snowpack created [${stopTimer(timer.backend)}]`);
 
@@ -352,6 +377,7 @@ export async function createRuntime(astroConfig: AstroConfig, { mode, logging }:
       astro: false,
     },
     mode,
+    target: 'frontend',
   });
   debug(logging, 'core', `frontend snowpack created [${stopTimer(timer.frontend)}]`);