Corelib.coffee is a JavaScript extension library that gives you the core classes that you've always wanted. Corelib is fully tested and fully documented and runs in any JavaScript environment, from the browser to the server, even on Xbox Live.
The array extensions are inspired by Ruby's core library. Simple things like each, remove, select, and include are the staples. Fancier methods such as partition, rand, and extremes often come in handy during game programming.
JavaScript has a language that allows for Number to provide many useful methods, but leaves us hanging. Corelib extends Number.prototype with the ever-popular clamp, times, and abs. It also provides the classic utilities floor, ceil, and round. But that's just the begining, there are many more including primeFactors.
String is one of the classes that default JavaScript does the most with, but why stop there. Inspired by the Rails inflector, there are many methods provided to alter strings such as titleize, underscore, and humanize. Some especially powerful methods like parse and constantize will no doubt come in handy.