CODEWITHSUNDEEP
mongoose
Chin
Chin

Reputation: 12712

Mongoose: check if object is mongoose object

anyone know what the simplest way to check whether an object is a mongoose object? Am I just best checking if toObject() is defined or is there a more efficient way. many thanks

Upvotes: 33

Views: 21638

Answers (10)

ZoM
ZoM

Reputation: 516

This, if you want to make sure it's the model you expect.

dog.constructor.modelName === 'Dog'

Upvotes: 1

Sandeep K Nair
Sandeep K Nair

Reputation: 2932

If you are working with typescript and using typescript imports then this helps

import { Mongoose } from 'mongoose';

...
const isMongooseModel = (object instanceof Mongoose.prototype.Model); // true if object is of type Model
const isMongooseDocument = (object instanceof Mongoose.prototype.Document); // true if object is of type Document
const isMongooseQuery = (object instanceof Mongoose.prototype.Query); // true if object is of type Query

Upvotes: 0

John
John

Reputation: 480

One way to determine is if you do a 

if (data.toObject)

it will return a Function statement if its true, will return undefined if it isn't;

Upvotes: 3

Kenany
Kenany

Reputation: 562

Try this:

var mongoose = require('mongoose');

function isMongoModel(yourObject){

    return yourObject.hasOwnProperty('schema') && yourObject.schema instanceof mongoose.Schema;
}

Upvotes: 1

Tony A.T. Mendina NT5TM
Tony A.T. Mendina NT5TM

Reputation: 119

My preferred way to determine if an object is a Mongoose model is almost as simple as the above, but not quite:

function isModel(obj) {
    obj = obj || {}
    return obj.prototype instanceof mongoose.Model
}

In the context where I use this, I don't want to get undefined back, but do need to verify that I haven't gotten a "3" or some such oddball value where I expect a model.

Of course, after thinking further about this, there's more than one way to be a "Mongoose object." I've sometimes mistaken a DTO for a Mongoose model and then misused it later, hence my test above...but if I just needed to verify that something is an instance, but for some reason could not know the instance type, I would do something like what Lukasz did above and look at the constructor base.

Upvotes: 11

djanowski
djanowski

Reputation: 5858

Another simple way:

const isMongooseModel = (object instanceof Mongoose.Model);

Upvotes: 4

Lukasz Czerwinski
Lukasz Czerwinski

Reputation: 15432

To check whether obj is a Mongoose object, use this snippet:

const _ = require('lodash');
const mongoose = require('mongoose');

function checkIfMongooseObject(obj) {
  return _.get(obj, 'constructor.base') instanceof mongoose.Mongoose;
}

Contrary to other solutions provided, this one is safe - it will never fail regardless type of obj (be it even String or Int).

Upvotes: 2

ac360
ac360

Reputation: 7835

The follwing for me in the case of checking when an ObjectID is a populated object or just an ObjectID:

if (object._id.constructor.name === 'ObjectID') {
    // Not a populated object, only its ID
}

Upvotes: 2

JohnnyHK
JohnnyHK

Reputation: 311935

You can check the object's prototype via the instanceof operator to confirm it's an instance of your mongoose model. Using the example schema from mongoosejs.com:

if (obj instanceof Cat) {
    // yes, it's a mongoose Cat model object
    ...
}

Upvotes: 37

mishimay
mishimay

Reputation: 4337

I'm using this

if (object.constructor.name === 'model') {
  // object is mongoose object
}

Upvotes: 22

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