Skip to content
Go to file


Failed to load latest commit information.
Latest commit message
Commit time


Implements schema inheritance and an optional discriminator key which is useful for storing different types of related documents in a collection and fetching them with the correct model type.


From version 0.2.1 mongoose-schema-extend is using harmony proxies. You will need to add the flag --harmony_proxies to your start command if you're using it, or use a previous version.


Install via NPM

$ npm install mongoose-schema-extend

Schema Inheritance

You just require the library to add schema extend method

var mongoose = require('mongoose'),
    extend = require('mongoose-schema-extend');
var Schema = mongoose.Schema;

var PersonSchema = new Schema({
  name : String
}, { collection : 'users' });

var EmployeeSchema = PersonSchema.extend({
  department : String

var Person = mongoose.model('Person', PersonSchema),
    Employee = mongoose.model('Employee', EmployeeSchema);

var Brian = new Employee({
  name : 'Brian Kirchoff',
  department : 'Engineering'


Discriminator Key

By adding the discriminatorKey schema option, a key is added to your saved documents with the model name and is used when finding documents of different types to set them to the correct model

var VehicleSchema = mongoose.Schema({ 
  make : String,
}, { collection : 'vehicles', discriminatorKey : '_type' });

var CarSchema = VehicleSchema.extend({
  year : Number
var BusSchema = VehicleSchema.extend({
  route : Number

var Vehicle = mongoose.model('vehicle', VehicleSchema),
    Car = mongoose.model('car', CarSchema),
    Bus = mongoose.model('bus', BusSchema);

var accord = new Car({ 
  make : 'Honda',
  year : 1999
var muni = new Bus({
  make : 'Neoplan',
  route : 33
}); { {
    // vehicles are saved with the _type key set to 'car' and 'bus'

At this point in MongoDB you will have documents similar to this

{ "_type" : "car", "make" : "Honda", "year" : 1999, "_id" : ObjectId("5024460368368a3007000002"), "__v" : 0 }
{ "_type" : "bus", "make" : "Neoplan", "route" : 33, "_id" : ObjectId("5024460368368a3007000003"), "__v" : 0 }

When querying, the objects model prototype will be set based on the _type field, so they are fully functional

Vehicle.find({}, function(err, vehicles) {
  console.log(vehicles[0]); // vehicles[0] instanceof Car === true
  console.log(vehicles[1]); // vehicles[1] instanceof Bus === true


To run the tests install dependencies

npm install

and then run

npm test


mongoose schema inheritance and discriminator key extension




No releases published


No packages published
You can’t perform that action at this time.