The next step beyond annotating your code is that TypeScript exposes classes and modules. Anders discusses in his talk (video on the TypeScript homepage) that the design of TypeScript classes and modules was heavily influenced by the current design of ES6 classes and modules, so it should continue to be familiar as the ECMAScript standard evolves.
Oh – and did I mention that it’s completely open-source and available for Node?
Check it out! And keep an eye on my blog – I’ll be talking about it as things evolve (and once I add TypeScript support to SyntaxHighlighter Evolved).