feat: support tailwindcss v3.1.x and v3.2.y (#21)

### Summary

Support Tailwind CSS v3.1 and Tailwind CSS v3.2.

---

### Details

Since Tailwind CSS support using ESM configuration in V3.3, we need to
use CJS configuration before that.

As mentioned in
#7 (comment),
we use `readFile` + `require.resolve` to get the version of
`tailwindcss/package.json`.

- If `satisfies(version, ^3.3.0)`, we will generate ESM configuration to
support both ESM and CJS.
- Else, we generate CJS configuration.

---

### Test plan

We setup two new entries in the testing matrix

- tailwindcss v3.1.0 with Ubuntu
- tailwindcss v3.1.0 with Windows

As you can see, the test is failing at
[0e05c6a](0e05c6a).

And after the fix is landed in
[e783415](e783415),
the test for old tailwindcss is passing.

---

### Related links

close: #18 

- Tailwind CSS v3.3:
  - https://github.com/tailwindlabs/tailwindcss/releases/tag/v3.3.0
  - tailwindlabs/tailwindcss#10785
- Tailwind CSS v3.2
  - https://github.com/tailwindlabs/tailwindcss/releases/tag/v3.2.0
- Tailwind CSS v3.1
  - https://github.com/tailwindlabs/tailwindcss/releases/tag/v3.1.0

Author: colinaaa

.github/workflows/test.yml

@@ -14,9 +14,13 @@ on:
 jobs:
   test:
     runs-on: ${{ matrix.os }}
+    name: Test tailwindcss@${{ matrix.tailwindcss }} on ${{ matrix.os }}
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest]
+        tailwindcss:
+          - latest
+          - "3.1.0" # The fist version that support `options.config`.
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
@@ -35,5 +39,11 @@ jobs:
       - name: Install Dependencies
         run: pnpm install && npx playwright install chromium
 
+      - name: Install tailwindcss@${{ matrix.tailwindcss }}
+        if: ${{ matrix.tailwindcss }} != "latest"
+        # Tailwind CSS <= v3.4.0 does not have correct TypeScript definition, which will make `rslib build` fail.
+        continue-on-error: true 
+        run: pnpm add -D -w tailwindcss@${{ matrix.tailwindcss }}
+
       - name: Run Test
         run: pnpm run test

package.json

@@ -35,8 +35,10 @@
     "@rslib/core": "^0.1.1",
     "@rsbuild/webpack": "^1.1.3",
     "@types/node": "^22.10.1",
+    "@types/semver": "^7.5.8",
     "playwright": "^1.49.0",
     "postcss": "^8.4.49",
+    "semver": "^7.6.3",
     "simple-git-hooks": "^2.11.1",
     "tailwindcss": "^3.4.15",
     "typescript": "^5.7.2"

pnpm-lock.yaml

@@ -1,5 +1,6 @@
 import { existsSync } from 'node:fs';
-import { mkdir, mkdtemp, writeFile } from 'node:fs/promises';
+import { mkdir, mkdtemp, readFile, writeFile } from 'node:fs/promises';
+import { createRequire } from 'node:module';
 import { tmpdir } from 'node:os';
 import path from 'node:path';
 import { pathToFileURL } from 'node:url';
@@ -286,26 +287,80 @@ class TailwindRspackPluginImpl {
       await mkdir(outputDir, { recursive: true });
     }
 
-    const configPath = path.resolve(outputDir, 'tailwind.config.mjs');
+    const [configName, configContent] = await this.#generateTailwindConfig(
+      userConfig,
+      entryModules,
+    );
+    const configPath = path.resolve(outputDir, configName);
 
-    const content = JSON.stringify(entryModules);
+    await writeFile(configPath, configContent);
 
-    await writeFile(
-      configPath,
-      existsSync(userConfig)
-        ? `\
+    return configPath;
+  }
+
+  async #resolveTailwindCSSVersion(): Promise<string> {
+    const require = createRequire(import.meta.url);
+    const pkgPath = require.resolve('tailwindcss/package.json', {
+      paths: [this.compiler.context],
+    });
+
+    const content = await readFile(pkgPath, 'utf-8');
+
+    const { version } = JSON.parse(content) as { version: string };
+
+    return version;
+  }
+
+  async #generateTailwindConfig(
+    userConfig: string,
+    entryModules: string[],
+  ): Promise<['tailwind.config.mjs' | 'tailwind.config.cjs', string]> {
+    const version = await this.#resolveTailwindCSSVersion();
+
+    const { default: satisfies } = await import(
+      'semver/functions/satisfies.js'
+    );
+
+    const content = JSON.stringify(entryModules);
+    if (satisfies(version, '^3.3.0')) {
+      // Tailwind CSS support using ESM configuration in v3.3.0
+      // See:
+      //   - https://github.com/tailwindlabs/tailwindcss/releases/tag/v3.3.0
+      //   - https://github.com/tailwindlabs/tailwindcss/pull/10785
+      //   - https://github.com/rspack-contrib/rsbuild-plugin-tailwindcss/issues/18
+      //
+      // In this case, we provide an ESM configuration to support both ESM and CJS.
+      return [
+        'tailwind.config.mjs',
+        existsSync(userConfig)
+          ? `\
 import config from '${pathToFileURL(userConfig)}'
 export default {
   ...config,
   content: ${content}
 }`
-        : `\
+          : `\
 export default {
   content: ${content}
 }`,
-    );
+      ];
+    }
 
-    return configPath;
+    // Otherwise, we provide an CJS configuration since TailwindCSS would always use `require`.
+    return [
+      'tailwind.config.cjs',
+      existsSync(userConfig)
+        ? `\
+const config = require(${JSON.stringify(userConfig)})
+module.exports = {
+  ...config,
+  content: ${content}
+}`
+        : `\
+module.exports = {
+  content: ${content}
+}`,
+    ];
   }
 }
 

src/TailwindCSSRspackPlugin.ts

@@ -0,0 +1,3 @@
+{
+  "type": "commonjs"
+}

test/cjs/config/package.json

@@ -1,2 +1,2 @@
 /** @type {import('tailwindcss').Config} */
-export default {};
+module.exports = {};

test/basic/tailwind.config.js test/cjs/config/tailwind.config.js

@@ -0,0 +1,99 @@
+import { dirname, resolve } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { expect, test } from '@playwright/test';
+import { createRsbuild } from '@rsbuild/core';
+import { pluginTailwindCSS } from '../../src';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+
+test('should build with relative config', async ({ page }) => {
+  const rsbuild = await createRsbuild({
+    cwd: __dirname,
+    rsbuildConfig: {
+      plugins: [
+        pluginTailwindCSS({
+          config: './config/tailwind.config.js',
+        }),
+      ],
+    },
+  });
+
+  await rsbuild.build();
+  const { server, urls } = await rsbuild.preview();
+
+  await page.goto(urls[0]);
+
+  const display = await page.evaluate(() => {
+    const el = document.getElementById('test');
+
+    if (!el) {
+      throw new Error('#test not found');
+    }
+
+    return window.getComputedStyle(el).getPropertyValue('display');
+  });
+
+  expect(display).toBe('flex');
+
+  await server.close();
+});
+
+test('should build with absolute config', async ({ page }) => {
+  const rsbuild = await createRsbuild({
+    cwd: __dirname,
+    rsbuildConfig: {
+      plugins: [
+        pluginTailwindCSS({
+          config: resolve(__dirname, './config/tailwind.config.js'),
+        }),
+      ],
+    },
+  });
+
+  await rsbuild.build();
+  const { server, urls } = await rsbuild.preview();
+
+  await page.goto(urls[0]);
+
+  const display = await page.evaluate(() => {
+    const el = document.getElementById('test');
+
+    if (!el) {
+      throw new Error('#test not found');
+    }
+
+    return window.getComputedStyle(el).getPropertyValue('display');
+  });
+
+  expect(display).toBe('flex');
+
+  await server.close();
+});
+
+test('should build without tailwind.config.js', async ({ page }) => {
+  const rsbuild = await createRsbuild({
+    cwd: __dirname,
+    rsbuildConfig: {
+      plugins: [pluginTailwindCSS()],
+    },
+  });
+
+  await rsbuild.build();
+  const { server, urls } = await rsbuild.preview();
+
+  await page.goto(urls[0]);
+
+  const display = await page.evaluate(() => {
+    const el = document.getElementById('test');
+
+    if (!el) {
+      throw new Error('#test not found');
+    }
+
+    return window.getComputedStyle(el).getPropertyValue('display');
+  });
+
+  expect(display).toBe('flex');
+
+  await server.close();
+});

test/cjs/index.test.ts

@@ -0,0 +1,11 @@
+import 'tailwindcss/utilities.css';
+
+function className() {
+  return 'flex';
+}
+
+const root = document.getElementById('root');
+const element = document.createElement('div');
+element.id = 'test';
+element.className = className();
+root.appendChild(element);

test/cjs/src/index.js

@@ -3,10 +3,16 @@ import { fileURLToPath } from 'node:url';
 import { expect, test } from '@playwright/test';
 import { createRsbuild } from '@rsbuild/core';
 import { pluginTailwindCSS } from '../../src';
+import { supportESM } from '../helper';
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
 
 test('should build with relative config', async ({ page }) => {
+  test.skip(
+    !supportESM(),
+    'Skip since the tailwindcss version does not support ESM configuration',
+  );
+
   const rsbuild = await createRsbuild({
     cwd: __dirname,
     rsbuildConfig: {
@@ -39,6 +45,11 @@ test('should build with relative config', async ({ page }) => {
 });
 
 test('should build with absolute config', async ({ page }) => {
+  test.skip(
+    !supportESM(),
+    'Skip since the tailwindcss version does not support ESM configuration',
+  );
+
   const rsbuild = await createRsbuild({
     cwd: __dirname,
     rsbuildConfig: {