Is there any way to create mongodb like _id strings without mongodb?

Question

I really like the format of the _ids generated by mongodb. Mostly because I can pull data like the date out of them client side. I'm planning to use another database but still want that type of _id for my document. How can I create these ids without using mongodb?

Thanks!

Solution 1

Object IDs are usually generated by the client, so any MongoDB driver would have code to generate them.

If you're looking for JavaScript, here's some code from the MongoDB Node.js driver:

https://github.com/mongodb/js-bson/blob/1.0-branch/lib/bson/objectid.js

And another, simpler solution:

https://github.com/justaprogrammer/ObjectId.js

Solution 2

A very easy pseudo ObjectId generator in javascript:

const ObjectId = (m = Math, d = Date, h = 16, s = s => m.floor(s).toString(h)) =>
    s(d.now() / 1000) + ' '.repeat(h).replace(/./g, () => s(m.random() * h))

Solution 3

I have a browser client that generates ObjectIds. I wanted to make sure that I employ the same ObjectId algorithm in the client as the one used in the server. MongoDB has js-bson which can be used to accomplish that.

If you are using javascript with node.

npm install --save bson

Using require statement

var ObjectID = require('bson').ObjectID;

var id  = new ObjectID();
console.log(id.toString());

Using ES6 import statement

import { ObjectID } from 'bson';

const id  = new ObjectID();
console.log(id.toString());

The library also lets you import using good old script tags but I have not tried this.

Solution 4

Extending Rubin Stolk's and ChrisV's answer in a more readable syntax (KISS).

function objectId () {
  return hex(Date.now() / 1000) +
    ' '.repeat(16).replace(/./g, () => hex(Math.random() * 16))
}

function hex (value) {
  return Math.floor(value).toString(16)
}

export default objectId

Solution 5

ruben-stolk's answer is great, but deliberately opaque? Very slightly easier to pick apart is:

const ObjectId = (rnd = r16 => Math.floor(r16).toString(16)) =>
    rnd(Date.now()/1000) + ' '.repeat(16).replace(/./g, () => rnd(Math.random()*16));

(actually in slightly fewer characters). Kudos though!

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Comments

[webjay]

and mongoose.Types.ObjectId.isValid say true

[honkskillet]

I used id.toHexString() to get the string.

[Grant Carthew]

Looks like the js file has been moved: github.com/mongodb/js-bson/blob/1.0-branch/lib/bson/objectid‌​.js

[Robert]

This should be the right answer... use the same code MongoDB does folks! I'm using bson 4.0.2 and it's working just fine for me. Note that the name is "ObjectId" (lowercase D)

[Tamas]

if you already have mongoose.Types, then you can also call new mongoose.Types.ObjectId()