Error management in javascript

error-examples.js

/* 
 * From the article "The Art of Error"
 * http://dailyjs.com/2014/01/30/exception-error/
 */

/* node example */
var assert = require('assert');
var util = require('util');

function NotFound(message) {
  Error.call(this);
  this.message = message;
}

util.inherits(NotFound, Error);

var error = new NotFound('/bitcoin-wallet not found');

assert(error.message);
assert(error instanceof NotFound);
assert(error instanceof Error);
assert.equal(error instanceof RangeError, false);

/* in http add status code */
function NotFound(message) {
  Error.call(this);
  // this line is for node / chrome. Other environments use different methods
  Error.captureStackTrace(this, arguments.callee);
  this.message = message;
  this.statusCode = 404;
}

/* than in express use something like this */
app.use(function(err, req, res, next) {
  console.error(err.stack);

  if (!err.statusCode || err.statusCode === 500) {
    emails.error({ err: err, req: req });
  }

  res.send(err.statusCode || 500, err.message);
});

/* 
 * In un sistema basato su callback verifico se il primo 
 * argomento della callback (l'errore) è settato e mi comporto di conseguenza.
 *
 * if (err) {
 *   return handleError(err);
 * }
 */