Meteor runs on top of Node.js. This means I/O activities such as reading a file or sending a request over the network won’t block the whole program. Instead, we provide callbacks that will be executed in the Event Loop later when those activities finish. Ok, I agree, that may not make a lot of sense. How about some cartoons!
In Meteor, a client-only collection is a database that is kept only on client side, without being synced with server (as a normal collection would be). Because the collection is not automatically synced, we will need to manually ‘push’ changes from server to client every time we want to publish something new.
For better illustration, let’s say we want to write a simple (and silly) app that retrieve and display current server’s time.
We start by defining a client-only collection: