Angular 2 production mode showing webpack-assets.json

My Angular2 app is working fine in dev mode. npm run server:dev

But when I am switching to production mode.npm run server:prod . I can see only webpack-assets.json in browser .

webpack-assets-json reads

{
  "main": {
  "js": "main.bundle.js"
 },
  "vendor": {
  "js": "vendor.bundle.js"
 },
  "polyfills": {
  "js": "polyfills.bundle.js"
 }
}

webpack.config.js reads

 switch (process.env.NODE_ENV) {
   case 'prod':
   case 'production':
     module.exports = require('./config/webpack.prod');
     break;
   case 'test':
   case 'testing':
     module.exports = require('./config/webpack.test');
     break;
   case 'dev':
   case 'development':
     default:
     module.exports = require('./config/webpack.dev');
  }

Not sure what is the mistake here.

via Dibshare