webpack.config.js

const path = require("path");
const HtmlWebpackPlugin = require("html-webpack-plugin");
const Dotenv = require("dotenv-webpack");

module.exports = (env) => ({
  entry: path.join(__dirname, "src", "index.jsx"),
  output: {
    path: path.resolve(__dirname, "dist"),
  },
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        exclude: /node_modules/,
        use: {
          loader: "babel-loader",
          options: {
            presets: ["@babel/preset-env", "@babel/preset-react"],
          },
        },
      },
      {
        test: /\.css$/,
        use: ["style-loader", "css-loader"],
      },
    ],
  },
  resolve: {
    extensions: ["*", ".js", ".jsx"],
  },
  plugins: [
    new HtmlWebpackPlugin({
      template: path.join(__dirname, "src", "index.html"),
    }),
    new Dotenv({
      path: path.join(
        __dirname,
        `.env${env.development ? ".development" : ""}`
      ),
    }),
  ],
  mode: "development",
});