Node 0.10 is about to be released -- the next stable version of Node. The most major change is the new streams API, which is designed to overcome some of the limitations found in previous versions. For a summary of the issues with streams in Node 0.8 and the new API, see: A New Streaming API for Node v0.10.
At first the new streams API seems quirky to work with, but I'm convinced my streams2 code is leaner. There are also new base classes for streams:
Transform. These classes actually cover some key functionality that was previously provided by third party modules.
Many of Node's core modules have streaming interfaces, and 0.10 adds streaming APIs to the crypto module.
EventEmitter has some changes. The documentation recommends using
util.inherits to extend the
EventEmitter class, and I'd add that it's a good idea to call the constructor as well. There's also a new
removeListener event which is emitted when listeners are removed, including when
removeAllListeners is called.
Node now has setImmediate and
clearImmediate -- there's a useful diagram by Shigeki Ohtsu that shows where
setImmediate is triggered: setImmediate semantics in Node 0.9.x.
For more details on API changes, see Api changes between v0.8 and v0.10.