webpack.config.js

const path = require('path');
const MiniCssExtractPlugin = require("mini-css-extract-plugin");
const libraryName = process.env.npm_package_name;
const autoprefixer = require('autoprefixer');

module.exports = (env, argv) => {
  return {
    mode: argv.mode,
    context: path.resolve(__dirname, 'src'),
    entry: "./entries/dist.js",
    output: {
      path: path.join(__dirname, '/dist'),
      filename: `${libraryName}.js`
    },
    module: {
      rules: [
        {
          test: /\.js$/,
          include: [
            path.resolve(__dirname, "src/scripts"),
            path.resolve(__dirname, "src/entries")
          ],
          use: 'babel-loader'
        },
        {
          test: /\.css$/,
          include: path.resolve(__dirname, "src/scripts"),
          use: [
            MiniCssExtractPlugin.loader,
            'css-loader',
            {
              loader: "postcss-loader",
              options: {
                postcssOptions: {
                  plugins: [
                    autoprefixer
                  ],
                },
              },
            },
          ]
        }
      ]
    },
    plugins: [
      new MiniCssExtractPlugin({
        filename: `${libraryName}.css`
      })
    ]
  };
};