Example of X new things in Meteor, leveraging local collection

stuff.html

<template name="stuff">
	<button name="show">Show {{newThingsCount}} new things</button>
	<ul>
		{{#each things}}
			<li>{{title}}</li>
		{{/each}}
	</ul>
</template>

stuff.js

var Things = new Meteor.Collection("things");
var LocalThings, processed = [];

if (Meteor.isServer) {
	Meteor.publish("things", function () {
		return Things.find();
	});
}

if (Meteor.isClient) {
	LocalThings = new Meteor.Collection(null);
	Meteor.subscribe("things");

	Meteor.autorun(function () {
		var things = Things.find();
		things.forEach(function (thing) {
			var cloned;
			if (processed.indexOf(thing._id) === -1) {
				processed.push(thing._id);
				cloned = _.clone(thing);
				delete cloned._id;
				cloned.new = true;
				LocalThings.insert(cloned);
			}
		});
	});

	Template.stuff.things = function () {
		return LocalThings.find({new: false});
	};

	Template.stuff.newThingsCount = function () {
		return LocalThings.find({new: true}).count();
	};

	Template.stuff.events({
		"click button[name='show']": function (evt, template) {
			LocalThings.update({new: true}, {$set: {new: false}});
		}
	});
}