Mongoose: extending schemas

Mongoose 3.8.1 now has support for Discriminators. A sample, from here: http://mongoosejs.com/docs/api.html#model_Model.discriminator

function BaseSchema() {  Schema.apply(this, arguments);  this.add({    name: String,    createdAt: Date  });}util.inherits(BaseSchema, Schema);var PersonSchema = new BaseSchema();var BossSchema = new BaseSchema({ department: String });var Person = mongoose.model('Person', PersonSchema);var Boss = Person.discriminator('Boss', BossSchema);

Some people have in other places suggested using utils.inherits to extend schemas. Another simple way would be to simply set up an object with settings and create Schemas from it, like so:

var settings = {  one: Number};new Schema(settings);settings.two = Number;new Schema(settings);

It's a bit ugly though, since you're modifying the same object. Also I'd like to be able to extend plugins and methods etc. Thus my preferred method is the following:

function UserSchema (add) {  var schema = new Schema({    someField: String  });  if(add) {    schema.add(add);  }  return schema;}var userSchema = UserSchema();var adminSchema = UserSchema({  anotherField: String});

Which happens to answer your second question that yes, you can add() fields. So to modify some properties of the Schema, a modified version of the above function would solve your problem:

function UserSchema (add, nameAndPhoneIsRequired) {  var schema = new Schema({    //...    firstname: {type: String, validate: firstnameValidator, required: nameAndPhoneIsRequired},    lastname: {type: String, validate: lastnameValidator, required: nameAndPhoneIsRequired},    phone: {type: String, validate: phoneValidator, required: nameAndPhoneIsRequired},  });  if(add) {    schema.add(add);  }  return schema;}

The simplest way for extending mongoose schema

import { model, Schema } from 'mongoose';const ParentSchema = new Schema({  fromParent: Boolean});const ChildSchema = new Schema({  ...ParentSchema.obj,  fromChild: Boolean // new properties come up here});export const Child = model('Child', ChildSchema);