From EXPRESS 4.0 Error HANDLING is much easier. The steps are as following:

• Create an express.js application and as there is no built-in middleware LIKE errorhandler in express 4.0, THEREFORE, the middleware need to be either installed or need to create a CUSTOM one.

Create a Middleware:

• Create a middleware as following:
  
  // error handler
  app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};
  // render the error page
  res.status(err.status || 500);
  res.render('error');
  });

Install Error Handler Middleware:

• Install errorhandler.
  npm install errorhandler --save
• Create a variable.
  var errorhandler = require('errorhandler')
• Use the middleware as following:
  
  if (process.env.NODE_ENV === 'development') {
  // only use in development
  app.use(errorhandler({log: errorNotification}))
  }
  function errorNotification(err, str, req) {
  var title = 'Error in ' + req.method + ' ' + req.url
  notifier.notify({
  title: title,
  message: str
  })
  }

From Express 4.0 Error handling is much easier. The steps are as following:

Create a Middleware:

Install Error Handler Middleware: