WARNING in configuration The 'mode' option has not been set, webpack will fallback to 'production' for this value. Set 'mode' option to 'development' or 'production' to enable defaults for each environment. You can also set it to 'none' to disable any default behavior. Learn more: https://webpack.js.org/concepts/mode/ module.exports = { mode: "development", // Add mode here to solve this warning entry: './src/main.js', // Bundle all assets from this location together output: { filename: 'index.js', // Output to this file path: path.resolve( __dirname, 'public' ), // In this location }