next.config.js

const path = require('path');
const glob = require('glob');

module.exports = {
  entry: ['server.js'],
  output: {
    filename: 'bundle.js'
  },
  target: 'node',
  webpack: (config) => {
    // Fixes npm packages that depend on `fs` module
    config.node = {
      fs: 'empty'
    }

    config.module.rules.push(
       {
         test: /\.(css|scss)/,
         loader: 'emit-file-loader',
         options: {
           name: 'dist/[path][name].[ext]'
         }
       }
     ,
       {
         test: /\.css$/,
         use: ['babel-loader', 'raw-loader', 'postcss-loader']
       }
     ,
       {
         test: /\.s(a|c)ss$/,
         use: ['babel-loader', 'raw-loader', 'postcss-loader',
           { loader: 'sass-loader',
             options: {
               includePaths: ['styles', 'node_modules']
                 .map((d) => path.join(__dirname, d))
                 .map((g) => glob.sync(g))
                 .reduce((a, c) => a.concat(c), [])
             }
           }
         ]
       }
    )

    return config
  }
}