js___webpack_fundamentals/webpack.config.js

const path = require("path"); // NodeJS builtin.

// Export a function returning config instead of a static config.
// The purpose is to allow use of the environment.
module.exports = env => {
  console.log(env);
  return {
    entry: "./src/",
    output: {
      filename: "bundle.js",
      path: path.join(__dirname, "dist") // path must be absolute.
    }
  };
};