Mongoose __v property - hide?

Question

Mongoose adds a '__v' property into Schema's for versioning - is it possible to disable this globally or globally hide it from all queries?

Coronal

Possible duplicate of What is the "__v" field in Mongoose – Eliseelisee

Answer 1

You can disable the "__v" attribute in your Schema definitions by setting the versionKey option to false. For example:

var widgetSchema = new Schema({ ... attributes ... }, { versionKey: false });

I don't think you can globally disable them, but can only do it per Schema. You can read more about Schema's options here. You might also find the Schema set method helpful.

Clintonclintonia

is it safe to disable "__v" attribute? will it cause any future issue if I disable it? – Gariepy

Is there a way to hide it from the returned docs from queries? – Cement

Is it safe? You can read the details here. TL:DR; Mongoose uses the version key to help avoid errors encountered by positional notation e.g. $set: { 'comments.3.body': updatedText }. If you read a document and use that update statement but someone modifies the comments array in the meantime you could update the wrong comment. With a version key you will get an exception in that case. – Intracranial

Answer 2

To disable '__v' property, which is not recommended, use the versionKey schema option:

var Schema = new Schema({...}, { versionKey: false });

To hide it from all queries, which sometimes can be not what you want too, use the select schema type option:

var Schema = new Schema({ __v: { type: Number, select: false}})

Artemisa

So how can I delete _id and __v before returning them to user? Is there any kind of mapping I can do? Mapping from schema to model would remove these two attributes and mapping from model to schema would let's say remove some fields user should not be able to edit but still see them. – Lacteous

Answer 3

Two ways:

1. {versionKey: false}

2. when you query, like model.findById(id).select('-__v')

'-' means exclude the field

Cheapen

Answer 4

define a toObject.transform function, and make sure you always call toObject when getting documents from mongoose.

var SomeSchema = new Schema({
    <some schema spec>
  } , {
    toObject: {
      transform: function (doc, ret, game) {
        delete ret.__v;
      }
    }
});

Mayramays

Alternatively you can call user.toObject({ versionKey: false }), which will hide __v version property. – Cory

Do you also need toJSON()? – Glooming

@Glooming No, not needed – Manwell

Answer 5

Try this it will remove _v from every query response.

// transform for sending as json
function omitPrivate(doc, obj) {
    delete obj.__v;
    return obj;
}

// schema options
var options = {
    toJSON: {
        transform: omitPrivate
    }
};
// schema
var Schema = new Schema({...}, options);

Dividers

Answer 6

You may not want to disable __v, other answers provide few links to answer why you shouldn't disable it.

I've used this library to hide the __v and _id

https://www.npmjs.com/package/mongoose-hidden

let mongooseHidden = require("mongoose-hidden")();

// This will add `id` in toJSON
yourSchema.set("toJSON", {
        virtuals: true,
    });

// This will remove `_id` and `__v` 
yourSchema.plugin(mongooseHidden);

Now __v will exist, but it won't be returned with doc.toJSON().

Hope it helps.

Kozak

Why use a library to do this silly simple transformation ? refer toJSON or toObject schema option instead. toObject() worked for me. – Manwell

You're right. Other answers have recommended the same thing. @NIKHILCM – Kozak

Answer 7

You can use a Query Middleware to exclude any field from the output. In your case you can use this:

// '/^find/' is a regex that matches queries that start with find
// like find, findOne, findOneAndDelete, findOneAndRemove, findOneAndUpdate
schema.pre(/^find/, function(next) {
    // this keyword refers to the current query
    // select method excludes or includes fields using + and -
    this.select("-__v");
    next();
});

For more information in docs lookup: Middlewares select method

Denticulation

Answer 8

For devs who are using nestJS

https://docs.nestjs.com/techniques/mongodb#model-injection

@Schema({
  versionKey: false, // this will prevent adding the __v when new record is created.
})
export class Cat {
  @Prop()
  name: string;

  @Prop()
  age: number;

  @Prop()
  breed: string;

  @Prop({ select: false }) // this will hide the __v when you do a select/find query
  __v: number;
}

Sabo

Answer 9

set this after connected to DB (server.js)

mongoose.modelNames().forEach(function (modelName) {
    mongoose.model(modelName).schema.set("versionKey", false);
});

Graniteware

doesnt work. still shows up. – Soluble

Answer 10

Yes, it is simple, just edit the "schema.js" file that is inside

"node_modules\mongoose\lib"

Search for "options = utils.options ({ ... versionKey: '__v'..." and change value "__v" to false.

This will change all post requests. (versionKey: '__v' => versionKey: false)

Dunlavy

This is terrible advice. – Regina

You should not change code inside node_modules. The content of this folder changes often with npm install and it should be added to .gitignore. Whatever you write there will be lost. – Downright