Collection2 relationship error due to missing collection object

Question

I am attempting to create a relationship between 2 collections, but one of the collections is not available to be referenced in the other. Specifically, I have 2 collections: Sites and ContentTypes. This is what they include:

// app/lib/collections/sites.js    
Sites = new Mongo.Collection('sites');

Sites.attachSchema(new SimpleSchema({
  name: {
    type: String,
    label: "Name",
    max: 100
  },
  client: {
    type: String,
    label: "Client",
    max: 100
  },
  created: {
    type: Date,
    autoValue: function() {
      if (this.isInsert) {
        return new Date;
      } else if (this.isUpsert) {
        return {$setOnInsert: new Date};
      } else {
        this.unset();  // Prevent user from supplying their own value
      }
    }
  }
}));

And here's the ContentTypes collection:

// app/lib/collections/content_types.js
ContentTypes = new Mongo.Collection('content_types');

ContentTypes.attachSchema(new SimpleSchema({
  name: {
    type: String,
    label: "Name",
    max: 100
  },
  machineName: {
    type: String,
    label: "Machine Name",
    max: 100
  },
  site:{
    type: Sites
  },
  created: {
    type: Date,
    autoValue: function() {
      if (this.isInsert) {
        return new Date;
      } else if (this.isUpsert) {
        return {$setOnInsert: new Date};
      } else {
        this.unset();  // Prevent user from supplying their own value
      }
    }
  }
}));

When I add the Sites reference to the ContentTypes schema, I the app crashes with the error:

ReferenceError: Sites is not defined at lib/collections/content_types.js:32:11

I haven't had much luck finding documentation for relationships in collection2 beyond this. It looks like the format referenced there is supposed to work based on this thread.

Answer 1

This is due to the order Meteor loads files. See section on File Load Order here:

There are several load ordering rules. They are applied sequentially to all applicable files in the application, in the priority given below:

1. HTML template files are always loaded before everything else
2. Files beginning with main. are loaded last
3. Files inside any lib/ directory are loaded next
4. Files with deeper paths are loaded next
5. Files are then loaded in alphabetical order of the entire path

e.g. rename app/lib/collections/sites.js to app/lib/collections/a_sites.js and the Sites variable will be defined when the content_types.js file is being loaded.