mongoose-reference-validator

validator for external reference documents

usage

schema setup

var mongoose = require('mongoose');
var ObjectId = mongoose.Schema.Types.ObjectId;
var mrf = require('mongoose-reference-validator');

var user = new mongoose.Schema({ name: String });
mongoose.model('user', user);

var car = new mongoose.Schema({
    name: String,
    driver : { type: ObjectId, ref: 'user' },
});
mrf(car);
mongoose.model('car', car);

document interaction

var jetta = new car({ name : "Jetta", user : user._id });
jetta.save(function(err, doc) {
    if (err && err.errors.driver.message) {
        console.log('user._id was invalid');
        console.log(err.errors.driver.message); // driver does not exist
    }
});

The validator will run when being saved, however, you can also run while updating.