Chai is a BDD / TDD assertion library for node and the browser that can be delightfully paired with any javascript testing framework.

Zombie.js is a lightweight framework for testing client-side JavaScript code in a simulated environment. No browser required.

RequireJS is a JavaScript file and module loader. It is optimized for in-browser use, but it can be used in other JavaScript environments, like Rhino and Node.

Natural is a general natural language facility for nodejs. Tokenizing, stemming, classification, phonetics, tf-idf, WordNet, string similarity, and some inflection are currently supported.