tmurphree/mongoose-cheatsheet.md

## mongoose-cheatsheet.md

      
    Raw
  

              mongoose-cheatsheet.md
            
          
    Definitely not comprehensive. This is meant to be a basic memory aid with links to get more details. I'll add to it over time.
Install

$ npm install mongoose --save

Connect

const mongoose = require('mongoose');
const connectionString = process.env.MONGO_URI || 'mongodb://localhost/databasenamegoeshere';

//overwrite deprecated Mongoose promise
mongoose.Promise = global.Promise;

//connect to mongodb
mongoose.connect(connectionString, {useMongoClient: true})
  .then(() => {
    console.log('Connected to database at ', new Date().toLocaleString());
  })
  .catch((err) => {
    console.error('Error connecting to the database: ', err);
  });

Defining a schema

const userSchema = new mongoose.Schema({
  name: {
    first: String,
    last: { type: String, trim: true }
  },
  age: { type: Number, min: 0 },
  posts: [ { title: String, url: String, date: Date } ],
  updated: { type: Date, default: Date.now }
});

SchemaTypes


String
Number
Date
Buffer
Boolean
Mixed
ObjectId
Array

SchemaTypes

SchemaType API

SchemaType#default

SchemaType#validate

get

set

select
Notes

Mixed types and dates that are modified using JavaScript Date methods are not hooked into mongoose change tracking logic. To save changes, let mongoose know about them using markModified('path') before calling save.
Instantiating a model

A model is a constructor compiled from a schema. Model instances represent documents.
    const User = mongoose.model('User', userSchema);

    var u = new User({
      name: {
        first: 'Tony',
        last: 'Pujals'
      },
      age: 99
    });
Query

The easiest way to query is to use Model.find, Model.findById, or Model.findOne methods.
These methods return a Query, which is not ideal.  If you use the .exec() method one of the above, you get a Promise.
To update something, use a Promise chain and work on the result.  The following code changes the name on one object with the name of 'Bob' to 'Sam':
MyModel.findOne({name: 'Bob'}).exec()
.then(function(data){
    data.name = 'Sam';
    return data.save();  //we need the return because .save() returns a Promise & we're in a 'then' already
    })
    .then(function() {
      //at this point the save is successful; we'd go to the catch otherwise
      res.status(204);   //use Express to send a response code
    })
    .catch(function(err) {
      console.error(err);
      res.status(400).json(err);  //use Express to send a response code
    });
You can also search on embedded documents: assuming you have a House where:
var HouseSchema = new mongoose.Schema({
    address: AddressSchema
});

var House = mongoose.model('House', HouseSchema);

House.findOne({'address.city': 'Tuscaloosa'}).exec();  
Assuming that the AddresseSchema has a field called 'city', 'address.city' looks for a House document where House.address.city is Tuscaloosa.
You can use .select to include and exclude fields: the following code selects the content, id, createdAt, and updatedAt fields and explicitly excludes the _id field by prefixing the field name with '-'.  _id is automatically included by default unless explicitly excluded.
Joke.find().select('content id createdAt updatedAt -_id').exec()
  .then(function(data) {
    res.status(200).json(data);
  })
  .catch(function(err) {
    console.error(err);

    res.status(400).json(err);
  });
You could also use Joke.find().select('-_id -__v').exec(), which excludes the _id and __v fields and returns all other fields.
Queries overview Read this first
query objects in the API docs
$where

    query.$where('this.comments.length > 10 || this.name.length > 5')

    // or

    query.$where(function() {
      return this.comments.length > 10 || this.name.length > 5;
    });
mongoDB $where
$all

mongoose $all

mongoDB $all
$count

http://mongoosejs.com/docs/api.html#query_Query-count
$distinct

http://mongoosejs.com/docs/api.html#query_Query-distinct
#elemMatch

http://mongoosejs.com/docs/api.html#query_Query-elemMatch
#equals

http://mongoosejs.com/docs/api.html#query_Query-equals
#exec

http://mongoosejs.com/docs/api.html#query_Query-exec
#exists

http://mongoosejs.com/docs/api.html#query_Query-exists
#find

http://mongoosejs.com/docs/api.html#query_Query-find
#findById

Finds a single document by its _id field. findById(id) is almost
equivalent to findOne({ _id: id }). If you want to query by a document's
_id, use findById() instead of findOne().
http://mongoosejs.com/docs/api.html#model_Model.findById
#findByIdAndRemove

http://mongoosejs.com/docs/api.html#model_Model.findByIdAndRemove
#findByIdAndUpdate

http://mongoosejs.com/docs/api.html#model_Model.findByIdAndUpdate
findOne

When executed, the first found document is passed to the callback.
http://mongoosejs.com/docs/api.html#query_Query-findOne
findOneAndRemove

http://mongoosejs.com/docs/api.html#query_Query-findOneAndRemove
findOneAndUpdate

http://mongoosejs.com/docs/api.html#query_Query-findOneAndUpdate
#gt

http://mongoosejs.com/docs/api.html#query_Query-gt
#gte

http://mongoosejs.com/docs/api.html#query_Query-gte
#hint

http://mongoosejs.com/docs/api.html#query_Query-hint
#in

http://mongoosejs.com/docs/api.html#query_Query-in
#lean

http://mongoosejs.com/docs/api.html#query_Query-lean
#limit

http://mongoosejs.com/docs/api.html#query_Query-limit
#lt

http://mongoosejs.com/docs/api.html#query_Query-lt
#lte

http://mongoosejs.com/docs/api.html#query_Query-lte
#maxScan

http://mongoosejs.com/docs/api.html#query_Query-maxScan
#merge

http://mongoosejs.com/docs/api.html#query_Query-merge
#mod

http://mongoosejs.com/docs/api.html#query_Query-mod
#ne

http://mongoosejs.com/docs/api.html#query_Query-ne
#nin

http://mongoosejs.com/docs/api.html#query_Query-nin
#nor

http://mongoosejs.com/docs/api.html#query_Query-nor
#or

http://mongoosejs.com/docs/api.html#query_Query-or
#populate

http://mongoosejs.com/docs/api.html#query_Query-populate
#read

http://mongoosejs.com/docs/api.html#query_Query-read
#regex

http://mongoosejs.com/docs/api.html#query_Query-regex
#remove


Removes all documents matching a query from a collection.

Ex.:
Album.remove({ artist: 'Anne Murray' }, callback);

To remove all documents in a collection (sort of like drop collection, except the collection exists afterwards):

Album.remove({}, callback);
?? this one ??
http://mongoosejs.com/docs/api.html#model_Model-collection
?? or this one ??
http://mongoosejs.com/docs/api.html#query_Query-remove
#save

Saves this document.  Returns a Promise.
http://mongoosejs.com/docs/api.html#model_Model-save
#select

http://mongoosejs.com/docs/api.html#query_Query-select
#setOptions

http://mongoosejs.com/docs/api.html#query_Query-setOptions
#size

http://mongoosejs.com/docs/api.html#query_Query-size
#skip

http://mongoosejs.com/docs/api.html#query_Query-skip
#slice

http://mongoosejs.com/docs/api.html#query_Query-slice
#snapshot

http://mongoosejs.com/docs/api.html#query_Query-snapshot
#sort

http://mongoosejs.com/docs/api.html#query_Query-sort
#stream

http://mongoosejs.com/docs/api.html#query_Query-stream
#tailable

http://mongoosejs.com/docs/api.html#query_Query-tailable
#toConstructor

http://mongoosejs.com/docs/api.html#query_Query-toConstructor
#update

http://mongoosejs.com/docs/api.html#model_Model.update
http://mongoosejs.com/docs/api.html#query_Query-update
#where

http://mongoosejs.com/docs/api.html#query_Query-where