Optimizing async joins for mongodb (mongoose) using async.js

I'm building a media viewer web app for a kiosk in node that uses data in mongo. To render the viewer, it gathers together all the Asset objects (representing video files), each of which belong to a Category, each of which belong to a Medium.

This is my first time using mongo and node together, so I decided to use async.js to organize the code, but I don't know if I'm doing things efficiently or not. Is there a better way to organize the data or perform the queries? Does this look remotely sane?

Additionally, I commented out some code I thought looked correct but would mysteriously overwrite the object simply by adding another key to it. What am I doing wrong?

models.js : mongoose models

var mongoose = require('mongoose');

/* Mediums... Film, Video, TV */
var mediumSchema = mongoose.Schema({
    name: String,
    id: String,
    description: String
});
var Medium = mongoose.model('mediums', mediumSchema);

/* Categories ... */
var categorySchema = mongoose.Schema({
    medium: String, // refers to medium.id, not medium._id
    name: String,
    shortName: String,
    years: String,
    description: String
});
var Category = mongoose.model('categories', categorySchema);

/* Assets */
var assetSchema = mongoose.Schema({
    title: String
,   year: Number
,   duration: Number
,   medium_info: String
,   copyright: String
,   extended_info: String
,   filename: String
,   category_id: mongoose.Schema.Types.ObjectId
});
var Asset = mongoose.model('assets', assetSchema);

exports.Medium = Medium;
exports.Category = Category;
exports.Asset = Asset;

viewer.js : the handler that retrieves all the data and renders the html

```
exports.index = function(req, res){
res.render('index');
};

exports.viewer = function(req, res) {
var models = require('./models');
var async = require("async");
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/test');

var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connec

A short review;

• Consider using JsHint

• Declare data with var, otherwise you are polluting the global namespace

• Consider err more often, the assumption that there will be no error will bite you

• Do not simply log to console.log, it is one of the most common bottlenecks

• Remove your commented out code, it keeps things clean

-
My assumption is that

• The meta data of ["FILM","VIDEO","TV"] does not change often

• The categories do no change often

I would generate a javascript file with the meta data and categories in 1 big Object Notation assignment, and re-generate it whenever mediums/categories change, this would greatly simplify your code, and make it way faster.

-
With Object Notation, this

data[mediumName] = {};
  data[mediumName]["categories"]  = categoryResults;
  data[mediumName]["description"] = mediumResults.description;
  data[mediumName]["name"] = mediumResults.name;

would be

data[mediumName] = {
    categories  : [];
    description : mediumResults.description;
    name : mediumResults.name;
  };

note that you override the results of data[mediumName]["categories"] = categoryResults; with data[mediumName].categories = [];

StackExchange Code Review Q#44776, answer score: 5