text: module.exports = env => {
      const isDev = env === 'dev';
      return {
          mode: isDev ? "development" : "production",
          entry: "./src/index.js",
          devtool: "sourcemap",
          output: {
              path: __dirname + "/dist",
              filename: `string-stream${isDev ? '' : '.min'}.js`
          },
          module: {
              rules: [
                  {
                      test: /\.js$/,
                      loader: 'babel-loader'
                  }
              ]
          }
      }; 
  };