perf: add experimental support for importModule

.github/workflows/nodejs.yml

@@ -80,6 +80,18 @@ jobs:
         if: matrix.os == 'windows-latest'
         run: npm i -g npm
 
+      - name: Get npm cache directory
+        id: npm-cache
+        run: |
+          echo "::set-output name=dir::$(npm config get cache)"
+
+      - uses: actions/cache@v1
+        with:
+          path: ${{ steps.npm-cache.outputs.dir }}
+          key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
+          restore-keys: |
+            ${{ runner.os }}-node-
+
       - name: Install dependencies
         run: npm i
 
@@ -93,3 +105,61 @@ jobs:
         uses: codecov/codecov-action@v1
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
+
+  test2:
+    name: Test - ${{ matrix.os }} - Node v${{ matrix.node-version }}, Webpack latest, experimentalUseImportModule
+
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+        node-version: [10.x, 12.x, 14.x]
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Setup Git
+        if: matrix.os == 'windows-latest'
+        run: git config --global core.autocrlf input
+
+      - uses: actions/checkout@v2
+
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - name: Use latest NPM on ubuntu/macos
+        if: matrix.os == 'ubuntu-latest' || matrix.os == 'macos-latest'
+        run: sudo npm i -g npm
+
+      - name: Use latest NPM on windows
+        if: matrix.os == 'windows-latest'
+        run: npm i -g npm
+
+      - name: Get npm cache directory
+        id: npm-cache
+        run: |
+          echo "::set-output name=dir::$(npm config get cache)"
+
+      - uses: actions/cache@v1
+        with:
+          path: ${{ steps.npm-cache.outputs.dir }}
+          key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
+          restore-keys: |
+            ${{ runner.os }}-node-
+
+      - name: Install dependencies
+        run: npm i
+
+      - name: Install webpack latest
+        run: npm i webpack@latest
+
+      - name: Run tests for webpack version latest with experimentalUseImportModule
+        run: npm run test:coverage -- --ci
+        env:
+          EXPERIMENTAL_USE_IMPORT_MODULE: 'true'
+
+      - name: Submit coverage data to codecov
+        uses: codecov/codecov-action@v1
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}

README.md

@@ -75,14 +75,15 @@ module.exports = {
 
 ### Plugin Options
 
-|                 Name                  |         Type         |                Default                | Description                                                |
-| :-----------------------------------: | :------------------: | :-----------------------------------: | :--------------------------------------------------------- |
-|      **[`filename`](#filename)**      | `{String\|Function}` |             `[name].css`              | This option determines the name of each output CSS file    |
-| **[`chunkFilename`](#chunkFilename)** | `{String\|Function}` |          `based on filename`          | This option determines the name of non-entry chunk files   |
-|   **[`ignoreOrder`](#ignoreOrder)**   |     `{Boolean}`      |                `false`                | Remove Order Warnings                                      |
-|        **[`insert`](#insert)**        | `{String\|Function}` | `document.head.appendChild(linkTag);` | Inserts `<link>` at the given position                     |
-|    **[`attributes`](#attributes)**    |      `{Object}`      |                 `{}`                  | Adds custom attributes to tag                              |
-|      **[`linkType`](#linkType)**      | `{String\|Boolean}`  |              `text/css`               | Allows loading asynchronous chunks with a custom link type |
+|                               Name                                |         Type         |                Default                | Description                                                                   |
+| :---------------------------------------------------------------: | :------------------: | :-----------------------------------: | :---------------------------------------------------------------------------- |
+|                    **[`filename`](#filename)**                    | `{String\|Function}` |             `[name].css`              | This option determines the name of each output CSS file                       |
+|               **[`chunkFilename`](#chunkFilename)**               | `{String\|Function}` |          `based on filename`          | This option determines the name of non-entry chunk files                      |
+|                 **[`ignoreOrder`](#ignoreOrder)**                 |     `{Boolean}`      |                `false`                | Remove Order Warnings                                                         |
+|                      **[`insert`](#insert)**                      | `{String\|Function}` | `document.head.appendChild(linkTag);` | Inserts `<link>` at the given position                                        |
+|                  **[`attributes`](#attributes)**                  |      `{Object}`      |                 `{}`                  | Adds custom attributes to tag                                                 |
+|                    **[`linkType`](#linkType)**                    | `{String\|Boolean}`  |              `text/css`               | Allows loading asynchronous chunks with a custom link type                    |
+| **[`experimentalUseImportModule`](#experimentalUseImportModule)** |     `{Boolean}`      |                `false`                | Use an experimental webpack API to execute modules instead of child compilers |
 
 #### `filename`
 
@@ -256,6 +257,16 @@ module.exports = {
 };
 ```
 
+#### `experimentalUseImportModule`
+
+Use an experimental webpack API to execute modules instead of child compilers.
+
+This improves performance and memory usage a lot, but isn't as stable as the normal approach.
+
+When combined with `experiments.layers`, this adds a `layer` option to the loader options to specify the layer of the css execution.
+
+You need to have at least webpack 5.33.2.
+
 ### Loader Options
 
 |              Name               |         Type         |              Default               | Description                                                                       |

package.json

@@ -73,7 +73,7 @@
     "npm-run-all": "^4.1.5",
     "prettier": "^2.2.1",
     "standard-version": "^9.1.0",
-    "webpack": "^5.27.1",
+    "webpack": "^5.33.2",
     "webpack-cli": "^4.5.0",
     "webpack-dev-server": "^3.7.2"
   },

src/index.js

@@ -309,7 +309,11 @@ class MiniCssExtractPlugin {
     this._sortedModulesCache = new WeakMap();
 
     this.options = Object.assign(
-      { filename: DEFAULT_FILENAME, ignoreOrder: false },
+      {
+        filename: DEFAULT_FILENAME,
+        ignoreOrder: false,
+        experimentalUseImportModule: false,
+      },
       options
     );
 
@@ -355,6 +359,18 @@ class MiniCssExtractPlugin {
       : // eslint-disable-next-line global-require
         require('webpack');
 
+    if (this.options.experimentalUseImportModule) {
+      if (!compiler.options.experiments) {
+        throw new Error(
+          'experimentalUseImportModule is only support for webpack >= 5.32.0'
+        );
+      }
+      if (typeof compiler.options.experiments.executeModule === 'undefined') {
+        // eslint-disable-next-line no-param-reassign
+        compiler.options.experiments.executeModule = true;
+      }
+    }
+
     // TODO bug in webpack, remove it after it will be fixed
     // webpack tries to `require` loader firstly when serializer doesn't found
     if (
@@ -399,7 +415,9 @@ class MiniCssExtractPlugin {
 
       normalModuleHook.tap(pluginName, (loaderContext) => {
         // eslint-disable-next-line no-param-reassign
-        loaderContext[pluginSymbol] = true;
+        loaderContext[pluginSymbol] = {
+          experimentalUseImportModule: this.options.experimentalUseImportModule,
+        };
       });
     });
 

src/loader-options.json

@@ -18,6 +18,9 @@
     "esModule": {
       "type": "boolean"
     },
+    "layer": {
+      "type": "string"
+    },
     "modules": {
       "type": "object",
       "additionalProperties": false,