A simple subclass of Error that allows to set http status using chaining api.
$ npm install error
var Error = require('error')
var err = new Error('message').http(404)
console.log(err.status)
// 404
throw new Error('message').http(404)
// Error 404: message
// at new Error (/tmp/error.js:7:16)
// at Error (/tmp/error.js:5:40)
// at Object.<anonymous> (/tmp/index.js:6:7)
// at Module._compile (module.js:456:26)