fix: remove purgecss (#440)

PurgeCSS doesn’t work with the latest version of PostCSS, far as I can tell.  It ends up removing too many classes.  It has always been sort of problematic and we only use it in a few MFEs, so I think it’s time for it to go.

README.rst

@@ -49,13 +49,6 @@ This MFE is configured via node environment variables supplied at build time. Se
 For more information see the document: `Micro-frontend applications in Open
 edX <https://edx.readthedocs.io/projects/edx-developer-docs/en/latest/micro-frontends-in-open-edx.html>`__.
 
-----------
-
-Notes
------
-
-The production Webpack configuration for this repo uses `Purgecss <https://www.purgecss.com/>`__ to remove unused CSS from the production css file. In ``webpack.prod.config.js`` the Purgecss plugin is configured to scan directories to determine what css selectors should remain. Currently the src/ directory is scanned along with all ``@edx/frontend-component*`` node modules and ``@edx/paragon``. **If you add and use a component in this repo that relies on HTML classes or ids for styling you must add it to the Purgecss configuration or it will be unstyled in the production build.**
-
 .. |Build Status| image:: https://api.travis-ci.org/edx/frontend-app-profile.svg?branch=master
    :target: https://travis-ci.org/edx/frontend-app-profile
 .. |Codecov| image:: https://img.shields.io/codecov/c/github/edx/frontend-app-profile

package-lock.json

@@ -15896,49 +15896,6 @@
       "integrity": "sha512-XRsRjdf+j5ml+y/6GKHPZbrF/8p2Yga0JPtdqTIY2Xe5ohJPD9saDJJLPvp9+NSBprVvevdXZybnj2cv8OEd0A==",
       "dev": true
     },
-    "purgecss": {
-      "version": "4.0.3",
-      "resolved": "https://registry.npmjs.org/purgecss/-/purgecss-4.0.3.tgz",
-      "integrity": "sha512-PYOIn5ibRIP34PBU9zohUcCI09c7drPJJtTDAc0Q6QlRz2/CHQ8ywGLdE7ZhxU2VTqB7p5wkvj5Qcm05Rz3Jmw==",
-      "dev": true,
-      "requires": {
-        "commander": "^6.0.0",
-        "glob": "^7.0.0",
-        "postcss": "^8.2.1",
-        "postcss-selector-parser": "^6.0.2"
-      },
-      "dependencies": {
-        "commander": {
-          "version": "6.2.1",
-          "resolved": "https://registry.npmjs.org/commander/-/commander-6.2.1.tgz",
-          "integrity": "sha512-U7VdrJFnJgo4xjrHpTzu0yrHPGImdsmD95ZlgYSEajAn2JKzDhDTPG9kBTefmObL2w/ngeZnilk+OV9CG3d7UA==",
-          "dev": true
-        }
-      }
-    },
-    "purgecss-webpack-plugin": {
-      "version": "4.0.3",
-      "resolved": "https://registry.npmjs.org/purgecss-webpack-plugin/-/purgecss-webpack-plugin-4.0.3.tgz",
-      "integrity": "sha512-YqmHRuKqjPhB+f/kURHYwlUR2QDcS8NSpCWrgQNICsSd8S2+tj40SDBav5b8KaSPQ8b/uXqrJxa/SnLyHK4BvQ==",
-      "dev": true,
-      "requires": {
-        "purgecss": "^4.0.3",
-        "webpack": "^5.4.0",
-        "webpack-sources": "^2.0.0"
-      },
-      "dependencies": {
-        "webpack-sources": {
-          "version": "2.3.0",
-          "resolved": "https://registry.npmjs.org/webpack-sources/-/webpack-sources-2.3.0.tgz",
-          "integrity": "sha512-WyOdtwSvOML1kbgtXbTDnEW0jkJ7hZr/bDByIwszhWd/4XX1A3XMkrbFMsuH4+/MfLlZCUzlAdg4r7jaGKEIgQ==",
-          "dev": true,
-          "requires": {
-            "source-list-map": "^2.0.1",
-            "source-map": "^0.6.1"
-          }
-        }
-      }
-    },
     "q": {
       "version": "1.5.1",
       "resolved": "https://registry.npmjs.org/q/-/q-1.5.1.tgz",

package.json

@@ -88,7 +88,6 @@
     "es-check": "5.2.4",
     "glob": "7.1.7",
     "husky": "6.0.0",
-    "purgecss-webpack-plugin": "4.0.3",
     "react-test-renderer": "16.14.0",
     "reactifex": "1.1.1",
     "redux-mock-store": "1.5.4"

webpack.prod.config.js

@@ -1,21 +0,0 @@
-const glob = require('glob');
-const PurgecssPlugin = require('purgecss-webpack-plugin');
-const { createConfig } = require('@edx/frontend-build');
-
-module.exports = createConfig('webpack-prod', {
-  plugins: [
-    // Scan files for class names and ids and remove unused css
-    new PurgecssPlugin({
-      paths: [].concat(
-        // Scan files in this app
-        glob.sync('src/**/*', { nodir: true }),
-        // Scan files in any edx frontend-component
-        glob.sync('node_modules/@edx/frontend-component*/**/*', { nodir: true }),
-        // Scan files in paragon
-        glob.sync('node_modules/@edx/paragon/**/*', { nodir: true }),
-      ),
-      // Protect react-css-transition class names
-      safelist: [/-enter/, /-appear/, /-exit/],
-    }),
-  ],
-});