mongoose reference another model

1Story.
2  findOne({ title: 'Casino Royale' }).
3  populate('author').
4  exec(function (err, story) {
5    if (err) return handleError(err);
6    console.log('The author is %s', story.author.name);
7    // prints "The author is Ian Fleming"
8  });

1const storySchema = Schema({
2  authors: [{ type: Schema.Types.ObjectId, ref: 'Person' }],
3  title: String
4});
5
6// Later
7
8const story = await Story.findOne({ title: 'Casino Royale' }).populate('authors');
9story.authors; // `[]`

1var mongoose = require('mongoose')
2  , Schema = mongoose.Schema
3
4var eventSchema = Schema({
5    title     : String,
6    location  : String,
7    startDate : Date,
8    endDate   : Date
9});
10
11var personSchema = Schema({
12    firstname: String,
13    lastname: String,
14    email: String,
15    gender: {type: String, enum: ["Male", "Female"]}
16    dob: Date,
17    city: String,
18    interests: [interestsSchema],
19    eventsAttended: [{ type: Schema.Types.ObjectId, ref: 'Event' }]
20});
21
22var Event  = mongoose.model('Event', eventSchema);
23var Person = mongoose.model('Person', personSchema);
24

1var mongoose = require('mongoose')
2  , Schema = mongoose.Schema
3
4var eventSchema = Schema({
5    title     : String,
6    location  : String,
7    startDate : Date,
8    endDate   : Date
9});
10
11var personSchema = Schema({
12    firstname: String,
13    lastname: String,
14    email: String,
15    gender: {type: String, enum: ["Male", "Female"]}
16    dob: Date,
17    city: String,
18    interests: [interestsSchema],
19    eventsAttended: [{ type: Schema.Types.ObjectId, ref: 'Event' }]
20});
21
22var Event  = mongoose.model('Event', eventSchema);
23var Person = mongoose.model('Person', personSchema);