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@solenoid
Created November 17, 2011 04:49
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javascript ObjectId generator
var mongoObjectId = function () {
var timestamp = (new Date().getTime() / 1000 | 0).toString(16);
return timestamp + 'xxxxxxxxxxxxxxxx'.replace(/[x]/g, function() {
return (Math.random() * 16 | 0).toString(16);
}).toLowerCase();
};
@vfa-tamhh
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Thanks! This code useful for me!

@cassiolacerda
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Thank you so much man!!!

@stubbyteam
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Thank you so much man!!!

@killshot13
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I appreciate that you shared this. It is a simple, logical function and integrates nicely with my Express backend.

@prakashsellathurai
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@solenoid what about the collision of this random id generation method?

@thauealfredo
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Perfect, thanks!!

@BathriNathan
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BathriNathan commented Oct 29, 2021

simple and quick solution. thanks

here is the function in coffee script:
mongoObjectId: () ->
timestamp = ((new Date).getTime() / 1000 | 0).toString(16)
timestamp + 'xxxxxxxxxxxxxxxx'.replace(/[x]/g, ->
(Math.random() * 16 | 0).toString 16
).toLowerCase()

@fabiofa87
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It saved my life. lol

Thanks dude!

@glafer
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glafer commented Feb 15, 2023

Thanks!

@mokiding
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mokiding commented Jul 3, 2023

@pedrogardim
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Thanks a lot, it was very useful!

I made a Golang version for a project

func mongoObjectId() string {
	ts := time.Now().UnixMilli() / 1000
	id := strconv.FormatInt(ts, 16)
	for i := 0; i < 16; i++ {
		id += fmt.Sprintf("%x", rand.Intn(16))
	}
	return id
}

@pacifiquem
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Impl in rust:

use chrono::Utc;
use rand::Rng;
use std::fmt;

fn mongo_object_id() -> String {
    let ts = Utc::now().timestamp_millis() / 1000;
    let mut id = format!("{:x}", ts);
    
    for _ in 0..16 {
        let random_digit = rand::thread_rng().gen_range(0..16);
        id.push_str(&format!("{:x}", random_digit));
    }

    id
}

fn main() {
    let object_id = mongo_object_id();
    println!("{}", object_id);
}

// [dependencies]
// chrono = "0.4"
// rand = "0.8"

@berdfandrade
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A simple python implementation

import time
import random

def mongo_object_id():
    timestamp = hex(int(time.time()))[2:]
    rest = ''.join([random.choice('0123456789abcdef') for _ in range(16)])
    
    return (timestamp + rest).lower()

@Myllaume
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I use console.log(new (require('bson').ObjectId)().toString()).

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