[node.js] nodejs mongodb object id to string

IN nodejs, with mongodb, mongoosejs as orm

I am doing this

I have a model, User

User.findOne({username:'someusername'}).exec(function(err,user){
console.log(user) //this gives full object with something like {_id:234234dfdfg,username:'someusername'}
//but

console.log(user._id) //give undefined.
})

Why? And how to get the _id to string then?

The result returned by find is an array.

Try this instead:

console.log(user[0]["_id"]);

Try this:

user._id.toString()

A MongoDB ObjectId is a 12-byte UUID can be used as a HEX string representation with 24 chars in length. You need to convert it to string to show it in console using console.log.

So, you have to do this:

console.log(user._id.toString());

try this: objectId.str;

see doc.

function encodeToken(token){
    //token must be a string .
    token = typeof token == 'string' ? token : String(token)
}

User.findOne({name: 'elrrrrrrr'}, function(err, it) {
    encodeToken(it._id)
})

In mongoose , the objectId is an object (console.log(typeof it._id)).

take the underscore out and try again:

console.log(user.id)

Also, the value returned from id is already a string, as you can see here.

I'm using it this way and it works.

Cheers

If you're using Mongoose, the only way to be sure to have the id as an hex String seems to be:

object._id ? object._id.toHexString():object.toHexString();

This is because object._id exists only if the object is populated, if not the object is an ObjectId

There are two ways to do this:

1. in stead of using user._id use user.id and it will return a string for you
2. If you really want to go the long way around you can use user._id.toString()

I faced the same problem and .toString() worked for me. I'm using mongojs driver. Here was my question

Mongodb find is not working with the Objectid

When using mongoose .

A representation of the _id is usually in the form (recieved client side)

{ _id: { _bsontype: 'ObjectID', id: <Buffer 5a f1 8f 4b c7 17 0e 76 9a c0 97 aa> },

As you can see there's a buffer in there. The easiest way to convert it is just doing <obj>.toString() or String(<obj>._id)

So for example

var mongoose = require('mongoose')
mongoose.connect("http://localhost/test")
var personSchema = new mongoose.Schema({ name: String })
var Person = mongoose.model("Person", personSchema)
var guy = new Person({ name: "someguy" })
Person.find().then((people) =>{
  people.forEach(person => {
    console.log(typeof person._id) //outputs object
    typeof person._id == 'string'
      ? null
      : sale._id = String(sale._id)  // all _id s will be converted to strings
  })
}).catch(err=>{ console.log("errored") })

Access the property within the object id like that user._id.$oid.

I'm using mongojs, and i have this example:

db.users.findOne({'_id': db.ObjectId(user_id)  }, function(err, user) {
   if(err == null && user != null){
      user._id.toHexString(); // I convert the objectId Using toHexString function.
   }
})

I hope this help.