Convert ObjectID (Mongodb) to String in JavaScript

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.

Try this:

objectId.str

See the doc.

> ObjectId() has the following attribute and methods: > > [...] > > * str - Returns the hexadecimal string representation of the object.

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.

in the shell

ObjectId("507f191e810c19729de860ea").str

in js using the native driver for node

objectId.toHexString()

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" }
  }}
])

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/

Acturally, you can try this:

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

ObjectId object + String will convert to String object.

If someone use in Meteorjs, can try:

In server: ObjectId(507f191e810c19729de860ea)._str.

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

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().

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

ObjectId(507f191e810c19729de860ea).valueOf();

In Javascript, String() make it easy

const id = String(ObjectID)

In Js do simply: _id.toString()

For example:

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

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);
}

Just use this : _id.$oid

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

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)
    })

You can use string formatting.

const stringId = `${objectId}`;

On aggregation use $addFields

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

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.

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

Mongoose documentation

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);
	});
}

...

You could use String

String(a['_id'])

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.