Feat: added the ability to pass an array of functions to the minify option

README.md

@@ -187,7 +187,7 @@ module.exports = {
 
 ### `minify`
 
-Type: `Function`
+Type: `Function|Array<Function>`
 Default: `undefined`
 
 Allows you to override default minify function.
@@ -196,6 +196,8 @@ Useful for using and testing unpublished versions or forks.
 
 > ⚠️ **Always use `require` inside `minify` function when `parallel` option enabled**.
 
+#### `Function`
+
 **webpack.config.js**
 
 ```js
@@ -240,13 +242,20 @@ module.exports = {
 };
 ```
 
+#### `Array`
+
+If an array of functions is passed to the `minify` option, the `minimizerOptions` must also be an array.
+The function index in the `minify` array corresponds to the options object with the same index in the `minimizerOptions` array.
+
 ### `minimizerOptions`
 
-Type: `Object`
+Type: `Object|Array<Object>`
 Default: `{ preset: 'default' }`
 
 Cssnano optimisations [options](https://cssnano.co/docs/optimisations).
 
+#### `Object`
+
 ```js
 module.exports = {
   optimization: {
@@ -267,6 +276,11 @@ module.exports = {
 };
 ```
 
+#### `Array`
+
+If an array of functions is passed to the `minify` option, the `minimizerOptions` must also be an array.
+The function index in the `minify` array corresponds to the options object with the same index in the `minimizerOptions` array.
+
 #### `processorOptions`
 
 Type: `Object`

src/index.js

@@ -7,6 +7,8 @@ import * as cssNanoPackageJson from 'cssnano/package.json';
 import pLimit from 'p-limit';
 import Worker from 'jest-worker';
 
+import { cssnanoMinify } from './utils';
+
 import * as schema from './options.json';
 import { minify as minifyFn } from './minify';
 
@@ -20,10 +22,8 @@ class CssMinimizerPlugin {
     });
 
     const {
-      minify,
-      minimizerOptions = {
-        preset: 'default',
-      },
+      minify = cssnanoMinify,
+      minimizerOptions,
       test = /\.css(\?.*)?$/i,
       warningsFilter = () => true,
       parallel = true,
@@ -281,34 +281,57 @@ class CssMinimizerPlugin {
               input = input.toString();
             }
 
+            const minifyFns =
+              typeof this.options.minify === 'function'
+                ? [this.options.minify]
+                : this.options.minify;
             const minimizerOptions = {
               name,
               input,
               inputSourceMap,
-              minimizerOptions: this.options.minimizerOptions,
-              minify: this.options.minify,
             };
 
-            try {
-              output = await (getWorker
-                ? getWorker().transform(serialize(minimizerOptions))
-                : minifyFn(minimizerOptions));
-            } catch (error) {
-              compilation.errors.push(
-                CssMinimizerPlugin.buildError(
-                  error,
-                  name,
-                  compilation.requestShortener,
-                  inputSourceMap &&
-                    CssMinimizerPlugin.isSourceMap(inputSourceMap)
-                    ? new SourceMapConsumer(inputSourceMap)
-                    : null
-                )
-              );
+            let warnings = [];
+
+            this.options.minimizerOptions = Array.isArray(
+              this.options.minimizerOptions
+            )
+              ? this.options.minimizerOptions
+              : [this.options.minimizerOptions];
+
+            for await (const [i, minifyFunc] of minifyFns.entries()) {
+              minimizerOptions.minify = minifyFunc;
+              minimizerOptions.minimizerOptions = this.options.minimizerOptions[
+                i
+              ];
+
+              try {
+                output = await (getWorker
+                  ? getWorker().transform(serialize(minimizerOptions))
+                  : minifyFn(minimizerOptions));
+              } catch (error) {
+                compilation.errors.push(
+                  CssMinimizerPlugin.buildError(
+                    error,
+                    name,
+                    compilation.requestShortener,
+                    inputSourceMap &&
+                      CssMinimizerPlugin.isSourceMap(inputSourceMap)
+                      ? new SourceMapConsumer(inputSourceMap)
+                      : null
+                  )
+                );
 
-              return;
+                return;
+              }
+
+              minimizerOptions.input = output.code;
+              minimizerOptions.inputSourceMap = output.map;
+              warnings = warnings.concat(output.warnings);
             }
 
+            output.warnings = warnings;
+
             if (output.map) {
               output.source = new SourceMapSource(
                 output.code,
@@ -426,4 +449,6 @@ class CssMinimizerPlugin {
   }
 }
 
+CssMinimizerPlugin.cssnano = cssnanoMinify;
+
 export default CssMinimizerPlugin;

src/minify.js

@@ -1,4 +1,3 @@
-const cssnano = require('cssnano');
 /*
  * We bring to the line here, because when passing result from the worker,
  * the warning.toString is replaced with native Object.toString
@@ -7,34 +6,6 @@ function warningsToString(warnings) {
   return warnings.map((i) => i.toString());
 }
 
-async function load(module) {
-  let exports;
-
-  try {
-    // eslint-disable-next-line import/no-dynamic-require, global-require
-    exports = require(module);
-
-    return exports;
-  } catch (requireError) {
-    let importESM;
-
-    try {
-      // eslint-disable-next-line no-new-func
-      importESM = new Function('id', 'return import(id);');
-    } catch (e) {
-      importESM = null;
-    }
-
-    if (requireError.code === 'ERR_REQUIRE_ESM' && importESM) {
-      exports = await importESM(module);
-
-      return exports.default;
-    }
-
-    throw requireError;
-  }
-}
-
 const minify = async (options) => {
   const {
     name,
@@ -44,70 +15,17 @@ const minify = async (options) => {
     minify: minifyFn,
   } = options;
 
-  if (minifyFn) {
-    const result = await minifyFn(
-      { [name]: input },
-      inputSourceMap,
-      minimizerOptions
-    );
-
-    return {
-      // TODO remove `css` in future major release
-      code: result.code || result.css,
-      map: result.map,
-      warnings: warningsToString(result.warnings || []),
-    };
-  }
-
-  const postcssOptions = {
-    to: name,
-    from: name,
-    ...minimizerOptions.processorOptions,
-  };
-
-  if (typeof postcssOptions.parser === 'string') {
-    try {
-      postcssOptions.parser = await load(postcssOptions.parser);
-    } catch (error) {
-      throw new Error(
-        `Loading PostCSS "${postcssOptions.parser}" parser failed: ${error.message}\n\n(@${name})`
-      );
-    }
-  }
-
-  if (typeof postcssOptions.stringifier === 'string') {
-    try {
-      postcssOptions.stringifier = await load(postcssOptions.stringifier);
-    } catch (error) {
-      throw new Error(
-        `Loading PostCSS "${postcssOptions.stringifier}" stringifier failed: ${error.message}\n\n(@${name})`
-      );
-    }
-  }
-
-  if (typeof postcssOptions.syntax === 'string') {
-    try {
-      postcssOptions.syntax = await load(postcssOptions.syntax);
-    } catch (error) {
-      throw new Error(
-        `Loading PostCSS "${postcssOptions.syntax}" syntax failed: ${error.message}\n\n(@${name})`
-      );
-    }
-  }
-
-  if (inputSourceMap) {
-    postcssOptions.map = {
-      annotation: false,
-      prev: inputSourceMap,
-    };
-  }
-
-  const result = await cssnano.process(input, postcssOptions, minimizerOptions);
+  const result = await minifyFn(
+    { [name]: input },
+    inputSourceMap,
+    minimizerOptions
+  );
 
   return {
-    code: result.css,
-    map: result.map && result.map.toString(),
-    warnings: warningsToString(result.warnings()),
+    // TODO remove `css` in future major release
+    code: result.code || result.css,
+    map: result.map,
+    warnings: warningsToString(result.warnings || []),
   };
 };
 

src/options.json

@@ -31,6 +31,10 @@
           "$ref": "#/definitions/Rule"
         }
       ]
+    },
+    "MinimizerOptions": {
+      "additionalProperties": true,
+      "type": "object"
     }
   },
   "title": "CssMinimizerWebpackPluginOptions",
@@ -62,8 +66,18 @@
     },
     "minimizerOptions": {
       "description": "Options for `cssMinimizerOptions`.",
-      "additionalProperties": true,
-      "type": "object"
+      "anyOf": [
+        {
+          "$ref": "#/definitions/MinimizerOptions"
+        },
+        {
+          "type": "array",
+          "minItems": 1,
+          "items": {
+            "$ref": "#/definitions/MinimizerOptions"
+          }
+        }
+      ]
     },
     "parallel": {
       "description": "Use multi-process parallel running to improve the build speed.",
@@ -82,7 +96,18 @@
     },
     "minify": {
       "description": "Allows you to override default minify function.",
-      "instanceof": "Function"
+      "anyOf": [
+        {
+          "instanceof": "Function"
+        },
+        {
+          "type": "array",
+          "minItems": 1,
+          "items": {
+            "instanceof": "Function"
+          }
+        }
+      ]
     }
   },
   "additionalProperties": false