Edit file File name : webpack.config.js Content :const path = require( 'path' ); const jetpackWebpackConfig = require( '@automattic/jetpack-webpack-config/webpack' ); module.exports = [ { entry: { index: './src/js/index.js', }, mode: jetpackWebpackConfig.mode, devtool: jetpackWebpackConfig.devtool, output: { ...jetpackWebpackConfig.output, path: path.resolve( './build' ), }, optimization: { ...jetpackWebpackConfig.optimization, }, resolve: { ...jetpackWebpackConfig.resolve, }, node: false, plugins: [ ...jetpackWebpackConfig.StandardPlugins() ], module: { strictExportPresence: true, rules: [ // Transpile JavaScript jetpackWebpackConfig.TranspileRule( { exclude: /node_modules\//, } ), // Transpile @automattic/jetpack-* in node_modules too. jetpackWebpackConfig.TranspileRule( { includeNodeModules: [ '@automattic/jetpack-' ], } ), // Handle CSS. jetpackWebpackConfig.CssRule( { extensions: [ 'css', 'sass', 'scss' ], extraLoaders: [ 'sass-loader' ], } ), // Handle images. jetpackWebpackConfig.FileRule(), ], }, externals: { ...jetpackWebpackConfig.externals, jetpackConfig: JSON.stringify( { consumer_slug: 'jetpack-backup', } ), }, }, ]; Save