webpack PurgeCSS webpack插件无法正常工作

Question

我要在使用webpack和purgecss-webpack-plugin的设置中从Clarity UI CSS文件中清除未使用的CSS。
但是，尽管CSS文件的大小从565kB减小到172kB，但由于我不使用任何文件，因此应将其减小到0kB。如果我使用Bootstrap做同样的事情，文件大小将减小到1kB。

为什么会这样，并且有解决办法？

我的文件夹结构如下：

|-dist  
|  
|-node_modules  
|  
|-src  
  |--index.js  
|  
|.babelrc  
|package.json  
|webpack.config.js 

我的package.json：

{
  "name": "webpack-clarity",
  "version": "1.0.0",
  "description": "",
  "private": true,
  "scripts": {
    "start": "node ./index.js",
    "build": "webpack"
  },
  "dependencies": {
    "@clr/ui": "^4.0.0",
    "bootstrap": "^4.5.2"
  },
  "devDependencies": {
    "@babel/core": "^7.10.4",
    "@babel/preset-env": "^7.10.4",
    "babel-loader": "^8.1.0",
    "css-loader": "^3.6.0",
    "glob": "^7.1.6",
    "html-webpack-plugin": "^4.3.0",
    "mini-css-extract-plugin": "^0.9.0",
    "optimize-css-assets-webpack-plugin": "^5.0.3",
    "purgecss-webpack-plugin": "^2.3.0",
    "webpack": "^4.44.1",
    "webpack-cli": "^3.3.12"
  }
}    

webpack.config.js

const path = require("path");
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
const OptimizeCssAssetsPlugin = require("optimize-css-assets-webpack-plugin");
const TerserPlugin = require("terser-webpack-plugin");
const glob = require("glob");
const PurgeCSSPlugin = require("purgecss-webpack-plugin");

module.exports = {
  mode: "production",
  entry: "./src/index.js",
  output: {
    filename: "main.js",
    path: path.resolve(__dirname, "dist"),
  },
  optimization: {
    minimizer: [new OptimizeCssAssetsPlugin(), new TerserPlugin()],
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: ["babel-loader"],
      },
      {
        test: /\.css$/,
        use: [MiniCssExtractPlugin.loader, "css-loader"],
      },
    ],
  },
  plugins: [
    new MiniCssExtractPlugin({ filename: "[name].css" }),
    new PurgeCSSPlugin({
      paths: glob.sync("./src/**/*.js", { nodir: true }),
    }),
  ],
};

.babelrc

{
  "presets": [
    [   
      "@babel/preset-env",
      {"modules": false}
    ]
  ]
}

index.js

import "../node_modules/@clr/ui/clr-ui.min.css";
import "../node_modules/bootstrap/dist/css/bootstrap.min.css";