locomotivejs and mongoose: passing promise variables to a controller

Question

preamble: I'm not sure if this is the best way to ask this question as I'm fairly sure it's more general than I'm making it and there's probably a global pattern that address my concern.

For the moment here's the question in the context of the original code that I'm working with.

Given a locomotivejs controller, let's call it Contact_Controller, with general structure like this:

'\controllers\contact_controller.js
var locomotive = require('locomotive')
    , Controller = locomotive.Controller
    , Contact = require('../models/contact')
    , sender = require('../helpers/sender')
    ;


var Contact_Controller = new Controller();

and then:

Contact_Controller.list = function() {
//Provides a list of all current (successful) contact attempts


var controller = this;

Contact.find({status: 1}, function(err, results) {
    if(err) {
        controller.redirect(controller.urlFor({controller: "dashboard", action: "error"}));
    }
    controller.contacts = results;
    controller.render();
});
};

and the model:

'/models/contact.js
var mongoose = require('mongoose')
, mongooseTypes = require('mongoose-types')
, pass = require('pwd')
, crypto = require('crypto')
, Schema = mongoose.Schema
, Email = mongoose.SchemaTypes.Email;


var ContactSchema = new Schema({
email: {type: Email, required: true},
subject: {type: String, required: true },
message: { type: String, required: true},
status: {type: Number, required: true, default: 1},
contact_time: {type: Date, default: Date.now}
});


module.exports = mongoose.model('contact', ContactSchema);

Inside the list action of the contact_controller I'd really rather not use controller = this; I generally prefer using redirect = this.redirect.bind(this); style localized binding to handle these sort of situations.

However, I can't think of a way to return the results to the controller's this object without creating a global variable version of this and having the promise's callback talk to that. Is there a better way to return the results variable or expose the contact_controller object in this context?

Answer 1

Do you mean this?

Contact.find({status: 1}, function(err, results) {
  if (err) {
    this.redirect(this.urlFor({this: "dashboard", action: "error"}));
    return; // you should return here, otherwise `render` will still be called!
  }
  this.contacts = results;
  this.render();
}.bind(this));
 ^^^^^^^^^^^ here you bind the controller object to the callback function