Mongoose: Testing query for embedded docs - http://stackoverflow.com/questions/16528539/mongoose-query-for-an-array-of-dictionaries

mongoose-embedded-doc-test.js

/**
 * Related to http://stackoverflow.com/questions/16528539/mongoose-query-for-an-array-of-dictionaries
 */

var mongoose = require('mongoose'),
    db = mongoose.connect('mongodb://localhost/test');

var blogSchema = new mongoose.Schema({
  group:  String,
  writing: [{
        post: String,
        name : Number
    }]
});

var Blog = mongoose.model('Blog', blogSchema);

var blogData = {
  group:  "Design Writing",
  writing: [{
        post: "A very very very short post." + Math.random(),
        name:  10
  }, {
  		_id: new mongoose.Types.ObjectId(),
        post: "An early morning post about everything.",
        name:  11
  }]
};

var postObject = blogData.writing[0],
	postObjectWithId = blogData.writing[1];

Blog.create(blogData, function(err){
	console.log(err ? err : 'Blog saved successfully!');

	// Example #1 Works!
	Blog.find({'writing.post': postObject.post})
	    .exec(function(err, res){ onBlogResult("Ex#1", err, res) });

	// Example #2 Works!
	Blog.find({})                        
	    .where('writing').in([postObjectWithId])
	    .exec(function(err, res){ onBlogResult("Ex#2", err, res) });

	// Example #3 Works - its the same as example #2!
	Blog.find({'writing': { $in: [ postObjectWithId ]}})
	    .exec(function(err, res){ onBlogResult("Ex#3", err, res) });

	// Example #4 Fails because of missing _id on postObject!
	Blog.find({'writing': { $in: [ postObject ]}})
	    .exec(function(err, res){ onBlogResult("Ex#4", err, res) });
})

function onBlogResult(ex, err, result){
	if(err || result.length == 0) 
		return console.log(ex, " - No matching document or Error");

	console.log(ex, " - Found blog: ", result);	
}

proof.txt

Blog saved successfully!

Ex#1  - Found blog:  [ { group: 'Design Writing',
    _id: 519288e1ceba8bc97e000003,
    __v: 0,
    writing: 
     [ { post: 'A very very very short post.0.8866961947642267',
         name: 10,
         _id: 519288e1ceba8bc97e000004 },
       { _id: 519288e1ceba8bc97e000002,
         post: 'An early morning post about everything.',
         name: 11 } ] } ]

Ex#2  - Found blog:  [ { group: 'Design Writing',
    _id: 519288e1ceba8bc97e000003,
    __v: 0,
    writing: 
     [ { post: 'A very very very short post.0.8866961947642267',
         name: 10,
         _id: 519288e1ceba8bc97e000004 },
       { _id: 519288e1ceba8bc97e000002,
         post: 'An early morning post about everything.',
         name: 11 } ] } ]

Ex#3  - Found blog:  [ { group: 'Design Writing',
    _id: 519288e1ceba8bc97e000003,
    __v: 0,
    writing: 
     [ { post: 'A very very very short post.0.8866961947642267',
         name: 10,
         _id: 519288e1ceba8bc97e000004 },
       { _id: 519288e1ceba8bc97e000002,
         post: 'An early morning post about everything.',
         name: 11 } ] } ]

Ex#4  - No matching document or Error