mongoose - w3toppers.com

Mongoose multiple connections

Mongoose handling connections via connections pool http://mongoosejs.com/docs/connections.html You can use server: {poolSize: 5} option for increase/decrease pool (number of parallel connections) If you need connections to different databases look here Mongoose and multiple database in single node.js project Example of multiple connections: var mongoose = require(‘mongoose’) var conn = mongoose.createConnection(‘mongodb://localhost/db1’); var conn2 = mongoose.createConnection(‘mongodb://localhost/db2’); var … Read more

$project in $lookup mongodb

You can use $lookup 3.6 syntax to $project the fields inside the $lookup pipeline User.aggregate([ { “$lookup”: { “from”: “schedules”, “let”: { “id”: “$_id.phone” }, “pipeline”: [ { “$match”: { “$expr”: { “$eq”: [“$customer.phone”, “$$id”] }}}, { “$project”: { “scheduleStart”: 1, “scheduleEnd”: 1 }} ], “as”: “user_detail” }} ])

Mongoose: ObjectId Comparisons fail inconsistently

A straight == (or ===) comparison will compare the two objects by reference, not value. So that will only evaluate to true if they both reference the very same instance. Instead, you should be using the equals method of ObjectID to compare their values: story._id.equals(offref.ref) As @bendytree notes in the comments, if either value could … Read more

Mongoose findOneAndUpdate and runValidators not working

required validators only fail when you try to explicitly $unset the key. This makes no sense to me but it’s what the docs say.

Mongoose: extending schemas

Mongoose 3.8.1 now has support for Discriminators. A sample, from here: http://mongoosejs.com/docs/api.html#model_Model.discriminator function BaseSchema() { Schema.apply(this, arguments); this.add({ name: String, createdAt: Date }); } util.inherits(BaseSchema, Schema); var PersonSchema = new BaseSchema(); var BossSchema = new BaseSchema({ department: String }); var Person = mongoose.model(‘Person’, PersonSchema); var Boss = Person.discriminator(‘Boss’, BossSchema);

Mongoose – finding subdocuments by criteria

You can use $elemMatch as a query-projection operator in the most recent MongoDB versions. From the mongo shell: db.parents.find( {‘children.age’: {$gte: 18}}, {children:{$elemMatch:{age: {$gte: 18}}}}) This filters younger children’s documents out of the children array: { “_id” : …, “children” : [ { “name” : “Margaret”, “age” : 20 } ] } { “_id” : … Read more

How to reference another schema in my Mongoose schema?

You can do so by using Population Population is the process of automatically replacing the specified paths in the document with document(s) from other collection(s). We may populate a single document, multiple documents, plain object, multiple plain objects, or all objects returned from a query. Suppose your Event Schema is defined as follows: var mongoose … Read more

How do I increment a Number value in Mongoose?

You can use $inc for this purpose. Try this: var id = req.body.id; Meme.findOneAndUpdate({_id :id}, {$inc : {‘post.likes’ : 1}}).exec(…); For more info on $inc, Please read MongoDB $inc documentation

Mongoose __v property – hide?

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. … Read more

MongoDB via Mongoose JS – What is findByID?

findById is a convenience method on the model that’s provided by Mongoose to find a document by its _id. The documentation for it can be found here. Example: // Search by ObjectId var id = “56e6dd2eb4494ed008d595bd”; UserModel.findById(id, function (err, user) { … } ); Functionally, it’s the same as calling: UserModel.findOne({_id: id}, function (err, user) … Read more