How to add variable into module context - Node.js

Question

How to add variable into module context - Node.js

I ran into a problem, where I need to bind some variable to context of module. I have two folders : Controllers and Models. In models, I have a model like this :

exports = {
  name: String,
  password: String
}

and the Controller looks like this :

exports = {
  onMessage: (message) {
    Model.doSomething();
  }
}

So I need to access the Model in the Controller while not require-ing it. I don't think loading the Model and giving it to global is good practice for this. I am looking for something like MyNodeJsModule.addVarToContext(Model);

The thing why I don't want to require model in controller is, I need the model to be loaded by external system and let the external system replace the Model by database-accessable model.

javascript
node.js

Answer 1

probably you have to change Controller like this?

module.exports = function(Model) {
  return {
      onMessage: function(message) {
         Model.doSomething();
      }
  };
}

Answer 2

Not quite sure what you need exactly but you can export Controller as a constructor and then bind each instance to a specific model.

So, in controller:

// Constructor
var Controller = function(model){
  this._model = model;
}

Controller.prototype.onMessage = function(message) {
  this._model.doSomething(message);
};

Controller.prototype.setModel = function(newModel){
  this._model = newModel;
}

exports.Controller = Controller;

Then (externally):

var ModelController = require('./controller').Controller;

var modelController1 = new ModelController(model1);
var modelController2 = new ModelController(model2);

modelController1.setModel(model2);
modelController2.setModel(model1);