Convert ObjectID (Mongodb) to String in JavaScript

Question

I want to convert ObjectID (Mongodb) to String in JavaScript. When I get a Object form MongoDB. it like as a object has: timestamp, second, inc, machine. I can't convert to string.

Transect

""+objectId or objectId.toString() whereby objectId is the variable I believe will do what your looking for. – Postrider

ObjectID loaded from MongoDB is a Object. if you use toString() function in Javascript, It will return [Object, Object]. – Transect

Odd, those functions were supposed to be implemented, I am sure that was fixed – Postrider

Dunno who marked this a duplicate of: https://mcmap.net/q/225280/-mongodb-objectid-to-string but you are seriously wrong... – Postrider

I think it's not bad question.! Your link is used for PHP. I need it in JavaScript.! – Transect

Indeed fortunately the stuff below is javascript :) – Postrider

@Transect what worked for you? i am also getting [Object, Object] – Beanie

I think there is some confusion in the answers as to whether you are talking about the mongodb console, or the javascript driver for node (both are JS, but are not identical in usage unfortunately) – Sunk

Answer 1

Try this:

// mongo shell
objectId.str

// mongo client, JS, Node.js
objectId.toString()

See the doc.

ObjectId() has the following attribute and methods:

• str - Returns the hexadecimal string representation of the object.

.toString() added from comment of @J.C.

Pedicab

i dont understand why, this isnt working for me when i do a console.log, i see the objectId as an object on the console – Beanie

This didn't work for me either. However, objectId.toString() did. – Birdsall

objectId.str is for mongo shell, objectId.toString() is for mongo client – Peel

What is the solution for monk? Neither .str or .toString() are working I am just getting an object, where the display is the exact string I am after but doesn't match equality checks against another string – Replace

Answer 2

Here is a working example of converting the ObjectId in to a string

> a=db.dfgfdgdfg.findOne()
{ "_id" : ObjectId("518cbb1389da79d3a25453f9"), "d" : 1 }
> a['_id']
ObjectId("518cbb1389da79d3a25453f9")
> a['_id'].toString // This line shows you what the prototype does
function () {
    return "ObjectId(" + tojson(this.str) + ")";
}
> a['_id'].str // Access the property directly
518cbb1389da79d3a25453f9
> a['_id'].toString()
ObjectId("518cbb1389da79d3a25453f9") // Shows the object syntax in string form
> ""+a['_id'] 
518cbb1389da79d3a25453f9 // Gives the hex string

Did try various other functions like toHexString() with no success.

Postrider

.toHexString() worked for me thanks Sammaye! mongodb.github.io/node-mongodb-native/api-bson-generated/… – Zoosporangium

As of 2022 there's no .str - the only viable way to convert an ObjectId to String is through .toString() – Octastyle

Answer 3

in the shell

ObjectId("507f191e810c19729de860ea").str

in js using the native driver for node

objectId.toHexString()

Joellyn

Nice answer, which points out the difference using native driver. – Frisse

This is the case if you're using a client like NoSQLBooster. Thanks. – Shirring

Answer 4

You can use $toString aggregation introduced in mongodb version 4.0 which converts the ObjectId to string

db.collection.aggregate([
  { "$project": {
    "_id": { "$toString": "$your_objectId_field" }
  }}
])

Damon

Answer 5

Use toString: var stringId = objectId.toString()

Works with the latest Node MongoDB Native driver (v3.0+):

http://mongodb.github.io/node-mongodb-native/3.0/

Furr

Answer 6

Acturally, you can try this:

> a['_id']
ObjectId("518cbb1389da79d3a25453f9")
> a['_id'] + ''
"518cbb1389da79d3a25453f9"

ObjectId object + String will convert to String object.

Redevelop

Answer 7

If someone use in Meteorjs, can try:

In server: ObjectId(507f191e810c19729de860ea)._str.

In template: {{ collectionItem._id._str }}.

Wriggler

Answer 8

Assuming the OP wants to get the hexadecimal string value of the ObjectId, using Mongo 2.2 or above, the valueOf() method returns the representation of the object as a hexadecimal string. This is also achieved with the str property.

The link on anubiskong's post gives all the details, the danger here is to use a technique which has changed from older versions e.g. toString().

Keble

Answer 9

In Javascript, String() make it easy

const id = String(ObjectID)

Shill

Answer 10

this works, You have mongodb object: ObjectId(507f191e810c19729de860ea), to get string value of _id, you just say

ObjectId(507f191e810c19729de860ea).valueOf();

Zeculon

Please improve your answer – Nicholenicholl

the string is wrapped inside ObjectId, so to get the wrapped value you use the answer i just provided @ Ivan Barayev – Zeculon

Answer 11

In Js do simply: _id.toString()

For example:

const myMongoDbObjId = ObjectID('someId');
const strId = myMongoDbObjId.toString();
console.log(typeof strId); // string

Concern

needs some explanation – Burette

@sidgate, added an example – Concern

Thanks @Concern this just save me from a serialization bug. – Wideopen

Answer 12

You can use string formatting.

const stringId = `${objectId}`;

Tungsten

Answer 13

toString() method gives you hex String which is kind of ascii code but in base 16 number system.

Converts the id into a 24 character hex string for printing

For example in this system:

"a" -> 61
"b" -> 62
"c" -> 63

So if you pass "abc..." to get objectId you will get "616263...".

As a result if you want to get readable string(char string) from objectId you have to convert it(hexCode to char).

To do this I wrote an utility function hexStringToCharString()

function hexStringToCharString(hexString) {
  const hexCodeArray = [];

  for (let i = 0; i < hexString.length - 1; i += 2) {
    hexCodeArray.push(hexString.slice(i, i + 2));
  }

  const decimalCodeArray = hexCodeArray.map((hex) => parseInt(hex, 16));

  return String.fromCharCode(...decimalCodeArray);
}

and there is usage of the function

import { ObjectId } from "mongodb";

const myId = "user-0000001"; // must contains 12 character for "mongodb": 4.3.0
const myObjectId = new ObjectId(myId); // create ObjectId from string

console.log(myObjectId.toString()); // hex string >> 757365722d30303030303031
console.log(myObjectId.toHexString()); // hex string >> 757365722d30303030303031

const convertedFromToHexString = hexStringToCharString(
  myObjectId.toHexString(),
);

const convertedFromToString = hexStringToCharString(myObjectId.toString());

console.log(`convertedFromToHexString:`, convertedFromToHexString);
//convertedFromToHexString: user-0000001
console.log(`convertedFromToString:`, convertedFromToString);
//convertedFromToHexString: user-0000001

And there is also TypeScript version of hexStringToCharString() function

function hexStringToCharString(hexString: string): string {
  const hexCodeArray: string[] = [];

  for (let i = 0; i < hexString.length - 1; i += 2) {
    hexCodeArray.push(hexString.slice(i, i + 2));
  }

  const decimalCodeArray: number[] = hexCodeArray.map((hex) =>
    parseInt(hex, 16),
  );

  return String.fromCharCode(...decimalCodeArray);
}

Arabelle

Answer 14

Just use this : _id.$oid

And you get the ObjectId string. This come with the object.

Terrell

You can see that at Strict MongoDB Extended JSON. – Terrell

Answer 15

Found this really funny but it worked for me:

    db.my_collection.find({}).forEach((elm)=>{

    let value = new String(elm.USERid);//gets the string version of the ObjectId which in turn changes the datatype to a string.

    let result = value.split("(")[1].split(")")[0].replace(/^"(.*)"$/, '$1');//this removes the objectid completely and the quote 
    delete elm["USERid"]
    elm.USERid = result
    db.my_collection.save(elm)
    })

Saddleback

Hello Hogan jerry, and welcome to StackOverflow! Please use code formatting only for the code parts, it will be easier to read :) Have a good day! – Roesch

Thanks... was too excited – Saddleback

Answer 16

On aggregation use $addFields

$addFields: {
      convertedZipCode: { $toString: "$zipcode" }
   }

Unitarian

Answer 17

Documentation of v4 (right now it's latest version) MongoDB NodeJS Driver says: Method toHexString() of ObjectId returns the ObjectId id as a 24 character hex string representation.

Tearing

Answer 18

In Mongoose, you can use toString() method on ObjectId to get a 24-character hexadecimal string.

Mongoose documentation

Chiron

Answer 19

Below three methods can be used to get the string version of id.
(Here newUser is an object containing the data to be stored in the mongodb document)

newUser.save((err, result) => {
  if (err) console.log(err)
  else {
     console.log(result._id.toString()) //Output - 23f89k46546546453bf91
     console.log(String(result._id))    //Output - 23f89k46546546453bf91
     console.log(result._id+"")         //Output - 23f89k46546546453bf91
  }
});

Crossly

Answer 20

user: {
  _id: ObjectId('234578fbf161fefa4b4efc')
  userId: ObjectId('234578fbf161fefa4b4efc')
}

console.log(user._id)            // new ObjectId('234578fbf161fefa4b4efc')
console.log(user.id)             // 234578fbf161fefa4b4efc

console.log(user.userId)         // new ObjectId('234578fbf161fefa4b4efc')
console.log(String(user.userId)) // 234578fbf161fefa4b4efc

Integrity

Answer 21

Use this simple trick, your-object.$id

I am getting an array of mongo Ids, here is what I did.

jquery:

...
success: function (res) {
   console.log('without json res',res);
    //without json res {"success":true,"message":" Record updated.","content":[{"$id":"58f47254b06b24004338ffba"},{"$id":"58f47254b06b24004338ffbb"}],"dbResponse":"ok"}

var obj = $.parseJSON(res);

if(obj.content !==null){
    $.each(obj.content, function(i,v){
        console.log('Id==>', v.$id);
    });
}

...

Cecillececily

Answer 22

You could use String

String(a['_id'])

Gayton

Answer 23

If you're using Mongoose along with MongoDB, it has a built-in method for getting the string value of the ObjectID. I used it successfully to do an if statement that used === to compare strings.

From the documentation:

Mongoose assigns each of your schemas an id virtual getter by default which returns the document's _id field cast to a string, or in the case of ObjectIds, its hexString. If you don't want an id getter added to your schema, you may disable it by passing this option at schema construction time.

Mentalism