Add the possibility to keep the js class names in the production build

docusaurus/docs/minify-keep-class-names.md

@@ -0,0 +1,23 @@
+---
+id: minify-keep-class-names
+title: Minify Keep Class names
+---
+
+The production build of Create React App uses the [terser-js](https://github.com/terser-js/terser) Webpack Plugin to minify the JS / TS sources. By default the class anmes are minified and replaced. If you want to keep the JavaScript Class Names you can set the env variable `KEEP_CLASS_NAMES` before you run the production build.
+
+Example with [cross-env](https://github.com/kentcdodds/cross-env#readme):
+
+```sh
+cross-env KEEP_CLASS_NAMES='true' && react-scripts build
+```
+
+In the `package.json` this would look like:
+
+```json
+{
+    ...
+    "scripts": {
+        "build": "cross-env KEEP_CLASS_NAMES='true' react-scripts build"
+    }
+}
+```

docusaurus/website/sidebars.json

@@ -36,7 +36,8 @@
       "adding-a-router",
       "adding-custom-environment-variables",
       "making-a-progressive-web-app",
-      "production-build"
+      "production-build",
+      "minify-keep-class-names"
     ],
     "Testing": ["running-tests", "debugging-tests"],
     "Back-End Integration": [

packages/react-scripts/config/webpack.config.js

@@ -44,6 +44,9 @@ const shouldUseSourceMap = process.env.GENERATE_SOURCEMAP !== 'false';
 // makes for a smoother build process.
 const shouldInlineRuntimeChunk = process.env.INLINE_RUNTIME_CHUNK !== 'false';
 
+// For keeping classNames while minifying the sources for production build
+const terserKeepClassNames = process.env.KEEP_CLASS_NAMES === 'true';
+
 const imageInlineSizeLimit = parseInt(
   process.env.IMAGE_INLINE_SIZE_LIMIT || '10000'
 );
@@ -195,6 +198,7 @@ module.exports = function(webpackEnv) {
         // This is only used in production mode
         new TerserPlugin({
           terserOptions: {
+            keep_fnames: terserKeepClassNames,
             parse: {
               // we want terser to parse ecma 8 code. However, we don't want it
               // to apply any minfication steps that turns valid ecma 5 code