Library author covers the relevant history here, http://disnetdev.com/blog/2011/08/23/Contracts.coffee-Contracts-For-JavaScript-and-CoffeeScript/ http://disnetd

Library author covers the relevant history here, http://disnetdev.com/blog/2011/08/23/Contracts.coffee-Contracts-For-JavaScript-and-CoffeeScript/ http://disnetdev.com/blog/2011/08/23/Contracts.coffee-Contra... This Lambda The Ultimate discussion on Benjamin C. Pierce's (Types And Programming Languages) talk Types Considered Harmful is also of interest - the gist being that contracts are useful because sometimes static types are just too damn hard - http://lambda-the-ultimate.org/node/2828 http://lambda-the-ultimate.org/node/2828 EDIT: Might as well link to Brendan Eich's talk Proxies Are Awesome!, http://www.slideshare.net/BrendanEich/metaprog-5303821 http://www.slideshare.net/BrendanEich/metaprog-5303821. I haven't really been following the Proxy thing and they seem quite useful. It's nice to see them applied so powerfully here.