MongooseJS: Subdoc Schemas in Separate Files - node.js

Question

Let's say that I have a schema called LeagueSchema, which needs to contain some general information about the league (e.g. the name, time created, etc.), as well as some more complicated objects (e.g. memberships). Because these memberships are not needed outside of the league, I don't think it's necessary for them to be their own collections. However, I think for the sake of modularity it would be best for these schemas to live in their own separate files.
It would look something like this:
league.js
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
var LeagueSchema = new Schema({
created: {
type: Date,
default: Date.now
},
updated: {
type: Date,
default: Date.now
},
name: {
type: String,
default: '',
trim: true
},
memberships: [MembershipSchema]
});
membership.js
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
var MembershipSchema = new Schema({
startDate: {
type: Date,
default: Date.now
},
endDate: {
type: Date,
default: null
},
user: {
type: Schema.ObjectId,
ref: 'User'
}
});
Unfortunately, this doesn't work. I get the following error:
ReferenceError: MembershipSchema is not defined
This is obviously happening because LeagueSchema is dependent on MembershipSchema, but I'm not sure what the best way to include it is. Can I define it as a dependency somehow? Or should I just include the file?
Also, is it bad practice to use subdocuments this way? Is there any reason it would be better to let all of these objects live in their own collections?

Answer 1

In your membership.js, export the membership sub-doc schema as a module:
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
var MembershipSchema = new Schema({
startDate: {
type: Date,
default: Date.now
},
endDate: {
type: Date,
default: null
},
user: {
type: Schema.ObjectId,
ref: 'User'
}
});
module.exports = MembershipSchema;
You can then require the exported module schema in your LeagueSchema document:
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var MembershipSchema = require('./membership');
var LeagueSchema = new Schema({
created: {
type: Date,
default: Date.now
},
updated: {
type: Date,
default: Date.now
},
name: {
type: String,
default: '',
trim: true
},
memberships: [MembershipSchema]
});
To answer your second question, as a general rule, if you have schemas that are re-used in various parts of your model, then it might be useful to define individual schemas for the child docs in separate files as so you don't have to duplicate yourself. A good example is when you use subdocuments in more that one model, or have two fields in a model that need to be distinguished, but still have the same subdocument structure.
If your memberships are not used elsewhere then rather treat the schema as an embedded document (document with schema of its own that is part of another document, such as items within an array):
Example definition and initialization:
var mongoose = require('mongoose'),
Schema = mongoose.Schema;
var MembershipSchema = new Schema({
startDate: {
type: Date,
default: Date.now
},
endDate: {
type: Date,
default: null
},
user: {
type: Schema.ObjectId,
ref: 'User'
}
});
var LeagueSchema = new Schema({
created: {
type: Date,
default: Date.now
},
updated: {
type: Date,
default: Date.now
},
name: {
type: String,
default: '',
trim: true
},
memberships: [MembershipSchema]
});
mongoose.model('League', LeagueSchema);

Answer 2

Your membership.js file should export the schema and the league.js file should import it. Then your code should should work.
In membership.js towards the bottom add:
module.exports = MembershipSchema;
In league.js, add
var MembershipSchema = require('membership.js');