Error Handling event emitter

gistfile1.txt

// in kraken-js/lib/util/errorUtil.js
var EventEmitter = require('events').EventEmitter;

function ErrorEmitter() {
    //anything to be sent custom by kraken (if we need to) with errors
    this.internalData = {
        from : "kraken"
    };
}

ErrorEmitter.prototype.__proto__ = EventEmitter.prototype;

ErrorEmitter.prototype = {
    //ANY FANCY SUPPORT
    //Eg: Check for something specific in error before emitting
    emitByType: function(error) {
        error.additionalInfo = this.internalData;
        this.emit((error.type || 'error'), error);
    }
};

module.exports = ErrorEmitter;

/**************************************************/


//request should have an error Handler attached to it before it reaches the controller logic in the app.
//still investigating which part of kraken this would go into.

var ErrorEmitter = require('./errorUtil');
req.errorEmitter = new ErrorEmitter(); // this should be done way before  the controllers in the app are hit.

/**************************************************/

//when a serverError happens instead of doing the rendering template with error like today, 
//we can emit an event to the app 
//this goes into kraken-js/lib/error.js

exports.serverError = function () {
    return function(err, req, res, next) {
        //req.errorHandler should already have been there
        //when the request got handed over to the app

        if(req.errorHandler) {
            req.errorHandler.emitByType(err);
        }
        //we would still need to pass err so that 
        //app does not continue doing the things it would normally do 
        //like no error happened. 
        next(err); 

    }
}

/**************************************************/
//on the app side when it gets called into controller logic
//req has errorHandler
//eg


server.get('/the/route', function(req, res) {
    req.errorHandler.on('specificType', function(data) {
        //specific type error handling
    };
    req.errorHandler.on('error', function(data) {
        //generic error handling
    })
});

1. It may be helpful to mark this as a js file
2. express is an eventemitter, fyi

😄