const withSass = require('@zeit/next-sass'); 
const { ANALYZE } = process.env
let AnalyzerPlugin; 
if(ANALYZE) {
  const { BundleAnalyzerPlugin } = require('webpack-bundle-analyzer'); 
  AnalyzerPlugin = BundleAnalyzerPlugin; 
}
module.exports = withSass({
  poweredByHeader: false,
  webpack: function (config, { isServer }) {
    if (ANALYZE) {
      config.plugins.push(new AnalyzerPlugin({
        analyzerMode: 'server',
        analyzerPort: isServer ? 8888 : 8889,
        openAnalyzer: true
      }))
    }
    return config
  }
});