Because of the structure and API model of the Node.js platform, some patterns are more biased or natural. The most obvious are the event-driven and the event stream patterns. They're not enforced but strongly engrained in the core API, and you're forced to use it in some parts of your application, so it's better to know how they work individually, how they work together, and how you can benefit from them.

Using the core API, you can access the filesystem, for example, to read a file with a single method and a callback; or you can request a read stream and then check the data and end events or pipe the stream to somewhere else. This is very useful when, say, you don't want to look at the file and just want to serve it to a client. This architecture was designed to work for core modules such as http and net. Similarly, when listening for client connections, you'll have to listen for a connection event (unless you have defined a connection listener during socket creation) and...