Test code

jest.config.js

@@ -0,0 +1,4 @@
+module.exports = {
+  testEnvironment: 'node',
+  snapshotResolver: './test/helpers/snapshotResolver.js',
+};

package.json

@@ -44,7 +44,7 @@
     "cacache": "^15.0.5",
     "cssnano": "^4.1.10",
     "find-cache-dir": "^3.3.1",
-    "jest-worker": "^26.1.0",
+    "jest-worker": "^26.2.0",
     "p-limit": "^3.0.2",
     "schema-utils": "^2.7.0",
     "serialize-javascript": "^4.0.0",
@@ -59,8 +59,9 @@
     "@commitlint/config-conventional": "^9.1.1",
     "@webpack-contrib/defaults": "^6.3.0",
     "@webpack-contrib/eslint-config-webpack": "^3.0.0",
-    "babel-jest": "^26.1.0",
+    "babel-jest": "^26.2.0",
     "commitlint-azure-pipelines-cli": "^1.0.3",
+    "copy-webpack-plugin": "^6.0.3",
     "cross-env": "^7.0.2",
     "css-loader": "^3.6.0",
     "del": "^5.1.0",
@@ -69,17 +70,18 @@
     "eslint-config-prettier": "^6.11.0",
     "eslint-plugin-import": "^2.22.0",
     "husky": "^4.2.5",
-    "jest": "^26.1.0",
+    "jest": "^26.2.0",
     "jest-junit": "^11.0.1",
     "lint-staged": "^10.2.11",
     "memfs": "^3.2.0",
     "mini-css-extract-plugin": "^0.9.0",
     "node-sass": "^4.14.1",
     "npm-run-all": "^4.1.5",
+    "postcss": "^7.0.32",
     "prettier": "^2.0.5",
     "sass-loader": "^9.0.2",
     "standard-version": "^8.0.2",
-    "webpack": "^4.44.0"
+    "webpack": "^4.44.1"
   },
   "keywords": [
     "cssnano",

src/index.js

@@ -41,6 +41,7 @@ class CssnanoPlugin {
       parallel = true,
       include,
       exclude,
+      minify,
     } = options;
 
     this.options = {
@@ -53,6 +54,7 @@ class CssnanoPlugin {
       parallel,
       include,
       exclude,
+      minify,
     };
 
     if (this.options.sourceMap === true) {
@@ -86,7 +88,7 @@ class CssnanoPlugin {
         sourceMap &&
         sourceMap.originalPositionFor({
           line: error.line,
-          column: error.col,
+          column: error.column,
         });
 
       if (original && original.source && requestShortener) {
@@ -95,7 +97,7 @@ class CssnanoPlugin {
             error.message
           } [${requestShortener.shorten(original.source)}:${original.line},${
             original.column
-          }][${file}:${error.line},${error.col}]${
+          }][${file}:${error.line},${error.column}]${
             error.stack
               ? `\n${error.stack.split('\n').slice(1).join('\n')}`
               : ''
@@ -106,7 +108,7 @@ class CssnanoPlugin {
       return new Error(
         `${file} from Cssnano Webpack Plugin\n${error.message} [${file}:${
           error.line
-        },${error.col}]${
+        },${error.column}]${
           error.stack ? `\n${error.stack.split('\n').slice(1).join('\n')}` : ''
         }`
       );
@@ -273,19 +275,13 @@ class CssnanoPlugin {
 
     const postcssOptions = { to: file, from: file, map: false };
 
-    if (inputSourceMap) {
-      postcssOptions.map = Object.assign(
-        { prev: inputSourceMap },
-        this.options.sourceMap
-      );
-    }
-
     const task = {
-      file,
       input,
       inputSourceMap,
       postcssOptions,
+      map: this.options.sourceMap,
       cssnanoOptions: this.options.cssnanoOptions,
+      minify: this.options.minify,
       callback,
     };
 
@@ -377,7 +373,7 @@ class CssnanoPlugin {
           if (worker) {
             taskResult = await worker.transform(serialize(task));
           } else {
-            taskResult = minifyFn(task);
+            taskResult = await minifyFn(task);
           }
         } catch (error) {
           taskResult = { error };
@@ -452,23 +448,9 @@ class CssnanoPlugin {
     );
 
     const optimizeFn = async (compilation, chunksOrAssets) => {
-      let assetNames;
-
-      if (CssnanoPlugin.isWebpack4()) {
-        assetNames = []
-          .concat(Array.from(compilation.additionalChunkAssets || []))
-          .concat(
-            Array.from(chunksOrAssets).reduce(
-              (acc, chunk) => acc.concat(Array.from(chunk.files || [])),
-              []
-            )
-          )
-          .filter((file) => matchObject(file));
-      } else {
-        assetNames = []
-          .concat(Object.keys(chunksOrAssets))
-          .filter((file) => matchObject(file));
-      }
+      const assetNames = Object.keys(
+        CssnanoPlugin.isWebpack4() ? compilation.assets : chunksOrAssets
+      ).filter((file) => matchObject(file));
 
       if (assetNames.length === 0) {
         return Promise.resolve();
@@ -545,4 +527,4 @@ class CssnanoPlugin {
   }
 }
 
-module.exports = CssnanoPlugin;
+export default CssnanoPlugin;

src/minify.js

@@ -1,12 +1,34 @@
 const cssnano = require('cssnano');
 
-const minify = (options) => {
-  const { input, postcssOptions, cssnanoOptions } = options;
+const minify = async (options) => {
+  const {
+    input,
+    postcssOptions,
+    cssnanoOptions,
+    map,
+    inputSourceMap,
+    minify: minifyFn,
+  } = options;
 
-  return cssnano.process(input, postcssOptions, cssnanoOptions);
+  if (minifyFn) {
+    return minifyFn({ input, postcssOptions, cssnanoOptions }, inputSourceMap);
+  }
+
+  if (inputSourceMap) {
+    postcssOptions.map = { prev: inputSourceMap, ...map };
+  }
+
+  const result = await cssnano.process(input, postcssOptions, cssnanoOptions);
+
+  return {
+    css: result.css,
+    map: result.map,
+    error: result.error,
+    warnings: result.warnings(),
+  };
 };
 
-function transform(options) {
+async function transform(options) {
   // 'use strict' => this === undefined (Clean Scope)
   // Safer for possible security issues, albeit not critical at all here
   // eslint-disable-next-line no-new-func, no-param-reassign
@@ -19,13 +41,9 @@ function transform(options) {
     `'use strict'\nreturn ${options}`
   )(exports, require, module, __filename, __dirname);
 
-  const result = minify(options);
+  const result = await minify(options);
 
-  if (result.error) {
-    throw result.error;
-  } else {
-    return result;
-  }
+  return result;
 }
 
 module.exports.minify = minify;

src/options.json

@@ -107,6 +107,10 @@
     "warningsFilter": {
       "description": "Allow to filter `cssnano` warnings.",
       "instanceof": "Function"
+    },
+    "minify": {
+      "description": "Allows you to override default minify function.",
+      "instanceof": "Function"
     }
   },
   "additionalProperties": false