test: custom css minifier

README.md

@@ -328,7 +328,6 @@ module.exports = {
  return {
  css: result.css,
  map: result.map,
- error: result.error,
  warnings: result.warnings(),
  };
  });
@@ -460,6 +459,38 @@ module.exports = {
 };
 ```
 
+### Using custom css minifier
+
+By default plugin uses [cssnano](https://github.com/cssnano/cssnano) package.
+It is possible to use another minify function.
+
+> ⚠️ **Always use `require` inside `minify` function when `parallel` option enabled**.
+
+**webpack.config.js**
+
+```js
+module.exports = {
+ optimization: {
+ minimize: true,
+ minimizer: [
+ new CssMinimizerPlugin({
+ minify: (data) => {
+ // eslint-disable-next-line global-require
+ const csso = require('csso');
+
+ const minifiedCss = csso.minify(data.input);
+
+ return {
+ css: minifiedCss.css,
+ map: minifiedCss.map,
+ };
+ },
+ }),
+ ],
+ },
+};
+```
+
 ## Contributing
 
 Please take a moment to read our contributing guidelines if you haven't yet done so.

package.json

@@ -64,6 +64,7 @@
  "copy-webpack-plugin": "^6.0.3",
  "cross-env": "^7.0.2",
  "css-loader": "^4.2.1",
+ "csso": "^4.0.3",
  "del": "^5.1.0",
  "del-cli": "^3.0.1",
  "eslint": "^7.7.0",

test/CssMinimizerPlugin.test.js

@@ -321,7 +321,6 @@ describe('CssMinimizerPlugin', () => {
  return {
  css: result.css,
  map: result.map,
- error: result.error,
  warnings: result.warnings(),
  };
  });
@@ -608,4 +607,32 @@ describe('CssMinimizerPlugin', () => {
  resolve();
  });
  });
+
+ it('should work with custom css minifier', async () => {
+ const compiler = getCompiler({
+ entry: {
+ foo: `${__dirname}/fixtures/test/foo.css`,
+ },
+ });
+
+ new CssMinimizerPlugin({
+ minify: (data) => {
+ // eslint-disable-next-line global-require
+ const csso = require('csso');
+
+ const minifiedCss = csso.minify(data.input);
+
+ return {
+ css: minifiedCss.css,
+ map: minifiedCss.map,
+ };
+ },
+ }).apply(compiler);
+
+ const stats = await compile(compiler);
+
+ expect(readAssets(compiler, stats, '.css')).toMatchSnapshot('assets');
+ expect(getErrors(stats)).toMatchSnapshot('error');
+ expect(getWarnings(stats)).toMatchSnapshot('warning');
+ });
 });

test/__snapshots__/CssMinimizerPlugin.test.js.snap.webpack4

@@ -139,6 +139,16 @@ exports[`CssMinimizerPlugin should work with child compilation: errors 1`] = `Ar
 
 exports[`CssMinimizerPlugin should work with child compilation: warnings 1`] = `Array []`;
 
+exports[`CssMinimizerPlugin should work with custom css minifier: assets 1`] = `
+Object {
+ "foo.css": "a{text-align:center}",
+}
+`;
+
+exports[`CssMinimizerPlugin should work with custom css minifier: error 1`] = `Array []`;
+
+exports[`CssMinimizerPlugin should work with custom css minifier: warning 1`] = `Array []`;
+
 exports[`CssMinimizerPlugin should write stdout and stderr of workers to stdout and stderr of main process in parallel mode: assets 1`] = `
 Object {
  "one.css": ".minify {};",

test/__snapshots__/CssMinimizerPlugin.test.js.snap.webpack5

@@ -149,6 +149,16 @@ exports[`CssMinimizerPlugin should work with child compilation: errors 1`] = `Ar
 
 exports[`CssMinimizerPlugin should work with child compilation: warnings 1`] = `Array []`;
 
+exports[`CssMinimizerPlugin should work with custom css minifier: assets 1`] = `
+Object {
+ "foo.css": "a{text-align:center}",
+}
+`;
+
+exports[`CssMinimizerPlugin should work with custom css minifier: error 1`] = `Array []`;
+
+exports[`CssMinimizerPlugin should work with custom css minifier: warning 1`] = `Array []`;
+
 exports[`CssMinimizerPlugin should write stdout and stderr of workers to stdout and stderr of main process in parallel mode: assets 1`] = `
 Object {
  "one.css": ".minify {};",