How to insert a doc into mongodb using mongoose and get the generated id?

Question

I'm using mongoose to operate mongodb. Now, for testing, I want to inserting some data into mongodb by native connection.

But the question is how to get the generated id after inserting?

I tried:

var mongoose = require('mongoose');  mongoose.connect('mongo://localhost/shuzu_test');  var conn = mongoose.connection;  var user = {     a: 'abc' };  conn.collection('aaa').insert(user);  console.log('User:'); console.log(user); 

But it prints:

{ a: 'abc' } 

There is no _id field.

Answer 1

You can generate _id yourself and send it to the database.

var ObjectID = require('mongodb').ObjectID;  var user = {   a: 'abc',   _id: new ObjectID() };  conn.collection('aaa').insert(user); 

This is one of my favourite features of MongoDB. If you need to create a number of objects, that are linked to each other, you don't need to make numerous round-trips between app and db. You can generate all ids in the app and then just insert everything.

Answer 2

If you use .save then you'll get the _id back in the callback function.

const User = require('../models/user.js');      var user = new User({   a: 'abc' });  user.save(function (err, results) {   console.log(results._id); });