How can I generate an ObjectId with mongoose?

Question

I'd like to generate a MongoDB ObjectId with Mongoose. Is there a way to access the ObjectId constructor from Mongoose?

This question is about generating a new ObjectId from scratch. The generated ID is a brand new universally unique ID.
Another question asks about creating an ObjectId from an existing string representation. In this case, you already have a string representation of an ID—it may or may not be universally unique—and you are parsing it into an ObjectId.

Dmitry Minkovsky · Accepted Answer · 2021-09-09T13:40:33.530

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You can find the ObjectId constructor on require('mongoose').Types. Here is an example:

var mongoose = require('mongoose');
var id = mongoose.Types.ObjectId();

id is a newly generated ObjectId.

Note: As Joshua Sherman points out, with Mongoose 6 you must prefix the call with new:

var id = new mongoose.Types.ObjectId();

You can read more about the Types object at Mongoose#Types documentation.

edited Sep 09 '21 at 13:40

answered Jul 27 '13 at 16:02

Dmitry Minkovsky

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how can you be sure that this is really unique? does mongoose any check before? – R01010010 Jun 06 '16 at 09:49
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@R01010010 check out how these are generated (Google). There's no check but it's probabilistic – Dmitry Minkovsky Jun 06 '16 at 13:13
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If you generate 16777216 within one second on the same machine, then you will probably get a duplicate. :) – joeytwiddle Jun 20 '16 at 02:58
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Correction: If you generate 16777216 within one millisecond on the same machine, then you will probably get a duplicate. – Evading Shadows Jul 11 '20 at 11:13
@joeytwiddle what is this number 16777216 ? – Saahithyan Vigneswaran Feb 24 '21 at 18:49
@SaahithyanVigneswaran it's 2^24, supposing you are using 24 bits for the random portion of the ID – Dmitry Minkovsky Feb 24 '21 at 19:20
[How are MongoDB's ObjectIds generated?](https://stackoverflow.com/questions/5817795/how-are-mongodbs-objectids-generated) The local counter is three bytes, or six hex chars. We can calculate: `256 ** 3 === 16 ** 6 === 16777216` – joeytwiddle Feb 25 '21 at 08:19
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looks like with mongoose 6 you have to add new ``new mongoose.Types.ObjectId()`` – Joshua Sherman Sep 09 '21 at 12:05

steampowered · Answer 2 · 2017-05-03T16:05:53.330

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You can create a new MongoDB ObjectId like this using mongoose:

var mongoose = require('mongoose');
var newId = new mongoose.mongo.ObjectId('56cb91bdc3464f14678934ca');
// or leave the id string blank to generate an id with a new hex identifier
var newId2 = new mongoose.mongo.ObjectId();

edited May 03 '17 at 16:05

answered Feb 22 '16 at 23:33

steampowered

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Poyoman · Answer 3 · 2019-04-09T01:00:53.733

I needed to generate mongodb ids on client side.

After digging into the mongodb source code i found they generate ObjectIDs using npm bson lib.

If ever you need only to generate an ObjectID without installing the whole mongodb / mongoose package, you can import the lighter bson library :

const bson = require('bson');
new bson.ObjectId(); // 5cabe64dcf0d4447fa60f5e2

Note: There is also an npm project named bson-objectid being even lighter

score 29 · Answer 4 · answered Jul 26 '19 at 06:39

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With ES6 syntax

import mongoose from "mongoose";

// Generate a new new ObjectId
const newId2 = new mongoose.Types.ObjectId();
// Convert string to ObjectId
const newId = new mongoose.Types.ObjectId('56cb91bdc3464f14678934ca');

answered Jul 26 '19 at 06:39

MattCochrane

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what's the diff between mongoose.Type and mongoose.Schema.Types ? – MartianMartian Feb 21 '22 at 11:18
mongoose.Schema.Types will be used to within your schema when you want to reference between collections. To create a single objectId within your code use simply mongoose.Types – stefano Mar 08 '22 at 13:43
@stefano, mongoose.Schema.Types.ObjectId and mongoose.Types.ObjectId, is the exactly same – Normal Sep 27 '22 at 17:30

Canonne Gregory · Answer 5 · 2023-04-07T15:13:58.920

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The import is mongo from mongoose, the node-mongodb-native driver. If you open the package you can verify !

import { mongo } from 'mongoose'
const newId = new mongo.ObjectId()

edited Apr 07 '23 at 15:13

answered Mar 19 '23 at 21:37

Canonne Gregory

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How can I generate an ObjectId with mongoose?

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