machwatt/Template.html

## Template.html
<head>
  <title>mongo-relation-test</title>
</head>

<body>
  {{> root}}
</body>

<template name="root">

  <h1>Authors</h1>
  {{#if loadingAuthors}}
  <p>Loading</p>
  {{else}}
  <ul>
    {{#each authors}}
    {{> author}}
    {{/each}}
  </ul>
  {{/if}}

  <h1>Books</h1>
  {{#if loadingBooks}}
  <p>Loading</p>
  {{else}}
  <ul>
    {{#each books}}
    {{> book}}
    {{/each}}
  </ul>
  {{/if}}
</template>

<template name="author">
  <li>{{name}} -- {{_id}}</li>
</template>

<template name="book">
  <li>{{name}} -- Author: {{author_name}}</li>
</template>

## Transform.js
Books = new Mongo.Collection("books");
Authors = new Mongo.Collection("authors");

if (Meteor.isClient) {
    /** Subscribe to check if connection is alive, needed for findOne() */
    var authorsHandle = Meteor.subscribe('authors');
    var booksHandle = Meteor.subscribe('books');

    Template.root.helpers({
        books: function () {
            return Books.find({}, {
                limit: 10, transform: function (book) {
                    var author = Authors.findOne({_id: book.author_id});
                    book.author_name = author.name;
                    return book;
                }
            });
        },
        authors: function () {
            return Authors.find({});
        },
        loadingAuthors: function () {
            return !authorsHandle.ready();
        },
        loadingBooks: function () {
            return !booksHandle.ready();
        }
    });
}

if (Meteor.isServer) {

    /** Create random authors and books on startup and connect via "random" author id */
    Meteor.startup(function () {
        if (Authors.find({}).count() <= 0) {
            var i;
            for (i = 0; i < 10; i++) {
                Authors.insert({name: "Author " + i, _id: "author" + i});
            }
        }

        if (Books.find({}).count() <= 0) {
            var i;
            for (i = 0; i < 10000; i++) {
                Books.insert({name: "book" + i, author_id: "author" + (Math.floor(Math.random() * 10) + 1)});
            }
        }
    });

    /** Use publish to check if db connection is ready*/
    Meteor.publish("authors", function () {
        return Authors.find();
    });
    Meteor.publish("books", function () {
        return Books.find();
    });
}

## TransformAlternative.js
/** As an alternative to Transform.js it is possible to insert the transform method into the whole Collection */

Books = new Mongo.Collection("books", {transform: function (book) {
    var author = Authors.findOne({_id: book.author_id});
    book.author_name = author.name;
    return book;
}});
	<head>
	<title>mongo-relation-test</title>
	</head>

	<body>
	{{> root}}
	</body>

	<template name="root">

	<h1>Authors</h1>
	{{#if loadingAuthors}}
	<p>Loading</p>
	{{else}}
	<ul>
	{{#each authors}}
	{{> author}}
	{{/each}}
	</ul>
	{{/if}}

	<h1>Books</h1>
	{{#if loadingBooks}}
	<p>Loading</p>
	{{else}}
	<ul>
	{{#each books}}
	{{> book}}
	{{/each}}
	</ul>
	{{/if}}
	</template>

	<template name="author">
	<li>{{name}} -- {{_id}}</li>
	</template>

	<template name="book">
	<li>{{name}} -- Author: {{author_name}}</li>
	</template>
	Books = new Mongo.Collection("books");
	Authors = new Mongo.Collection("authors");

	if (Meteor.isClient) {
	/** Subscribe to check if connection is alive, needed for findOne() */
	var authorsHandle = Meteor.subscribe('authors');
	var booksHandle = Meteor.subscribe('books');

	Template.root.helpers({
	books: function () {
	return Books.find({}, {
	limit: 10, transform: function (book) {
	var author = Authors.findOne({_id: book.author_id});
	book.author_name = author.name;
	return book;
	}
	});
	},
	authors: function () {
	return Authors.find({});
	},
	loadingAuthors: function () {
	return !authorsHandle.ready();
	},
	loadingBooks: function () {
	return !booksHandle.ready();
	}
	});
	}

	if (Meteor.isServer) {

	/** Create random authors and books on startup and connect via "random" author id */
	Meteor.startup(function () {
	if (Authors.find({}).count() <= 0) {
	var i;
	for (i = 0; i < 10; i++) {
	Authors.insert({name: "Author " + i, _id: "author" + i});
	}
	}

	if (Books.find({}).count() <= 0) {
	var i;
	for (i = 0; i < 10000; i++) {
	Books.insert({name: "book" + i, author_id: "author" + (Math.floor(Math.random() * 10) + 1)});
	}
	}
	});

	/** Use publish to check if db connection is ready*/
	Meteor.publish("authors", function () {
	return Authors.find();
	});
	Meteor.publish("books", function () {
	return Books.find();
	});
	}
	/** As an alternative to Transform.js it is possible to insert the transform method into the whole Collection */

	Books = new Mongo.Collection("books", {transform: function (book) {
	var author = Authors.findOne({_id: book.author_id});
	book.author_name = author.name;
	return book;
	}});