Mongoose Relationships

A plugin for Mongoose for model relationships and helpers.

Goals

• Be unobtrusive and compliant with the ways of Mongoose (coding style, testing, API).

Usage

var mongoose = require('mongoose');
require('mongo-relation');

One to Many (belongsTo/hasMany)

var postSchema = new mongoose.Schema({});
postSchema.hasMany('comments', { dependent: 'destroy|delete|nullify' });
var Post = mongoose.model('Post', postSchema);

var commentSchema = new mongoose.Schema({});
commentSchema.belongsTo('post');
var Comment = mongoose.model('Comment', commentSchema);

create

Creates a child document associated to the parent.

• {Object|Array} objs child document(s) // simple objects
• {Function} callback callback(err, docs)
  • {Error} err error from mongoose
  • {Document|Array} docs Array or single persisted model

var postSchema = new mongoose.Schema({ content: String });
postSchema.hasMany('comments', { dependent: 'destroy|delete|nullify' });

var commentSchema = new mongoose.Schema({ content: String });
commentSchema.belongsTo('post');

var post = new Post({ content: "Relations are helpful." });

post.comments.create({ content: "I agree!" }, function(err, comment){
  console.assert(comment.content == "I agree!", "comment belongsTo post.");
  console.assert(post._id == comment.post, "comment belongsTo post.");
  console.assert(!comment.isNew, "comment has been saved.");
  console.assert(comment instanceOf Comment, "comment is a Comment.");
});

post.comments.create({ content: "+1" }, { content: "Yup!" }, function(err, comments){
  console.assert(comments.length == 2, "created two documents.");
  comments.forEach(function (comment) {
    console.assert(post._id == comment.post, "comment belongsTo post.");
    console.assert(!comment.isNew, "comment has been saved.");
    console.assert(comment instanceOf Comment, "comment is a Comment.");
  });
});

build

Instantiates children/a child document(s) with the appropriate associations.

• {Object|Array} objs child document(s) // simple objects

var comment = post.comments.build({comment: "First!"});
console.assert(comment.post == post._id, "associated");
console.assert(comment.isNew, "not saved");

var post = new Post({ content: "Relations are easy." });
var comments = post.comments.build({ comment: "First!" }, { comment: "LOL" });
console.assert(comments.length == 2);
comments.forEach(function (comment) {
  console.assert(comment.post === post._id, "associated");
  console.assert(comment.isNew, "not saved");
});

concat

Associates & saves initialized document(s) with the appropriate associations.

• {Document|Array} docs documents to associate. // mongoose documents
• {Function} callback callback(err, docs)
  • {Error} err error from mongoose
  • {Document|Array} docs Array or single persisted document(s)

var post = new Post({ content: "Concating is great." });
var comment = new Comment();
post.comments.concat(comment, function(err, comment){
  console.assert(comment.post === post._id, "associated");
  console.assert(!comment.isNew, "saved");
});

var comments = [new Comment(), new Comment()];
post.comments.concat(comments, function(err, comments){
  console.assert(comments.length == 2);
  comments.forEach(function (comment) {
    console.assert(comment.post === post._id, "associated");
    console.assert(!comment.isNew, "saved");
  });
});

// existing doc

var comment = new Comment();
comment.save(function (err, comment) {
  post.comments.concat(comment, function(err, comment){
	console.assert(comment.post === post._id, "associated");
	console.assert(!comment.isNew, "saved");
  });
});

append

Sugar for #concat

find

Inject params for the association, then fallback on Model.find

• {Object} docs (optional) query conditions
• {String} fields (optional) fields to populate
• {Object} options (optional) query options
• {String} callback (optional) callback(err, docs)
  • {Error} err error from mongoose
  • {Document} doc Found document

var postOne = new Post({ content: "Find all the things." })
  , postTwo = new Post({ content: "Found all the things." });

postOne.comments.create({ content: "+1" }, function(err){
  postTwo.comments.create({ content: "+1" }, function(err){

    postOne.comments.find({ comment: "+1" }, function(err, comments){
      console.assert(comments.length == 1);
      console.assert(comments[0].post == postOne._id, "found the correct comment");

      var criteria = postTwo.comments.find({ comment: "+1" });
      console.assert(criteria._conditions.post == postTwo._id, "The association has been added to the query.");
      console.assert(criteria._conditions.comment == "+1", "keeps original query.");

      criteria.exec(function(err, comments){
        console.assert(comments.length == 1);
        console.assert(comments[0].post == postTwo._id, "found the correct comment");
      });
    });
  });
});

Todo

• Document belongsTo
• add touch to hasMany
• add touch to belongsTo
• Refactor hasAndBelongsToMany
• Document hasAndBelongsToMany
• Add embedsMany
• Add emdedsOne