[_harry]

Anecdotally, Airbnb's mobile website (http://m.airbnb.com) was written entirely in CoffeeScript.

We had never used CoffeeScript before the project and we finished what you see today in about 6 weeks with a team of 3.

The project codebase looks like it was written with consistent style all the way through, which can be harder to do with JavaScript when it's 3am and all you want to do is make it work (when you start to get lazy). It was nice knowing that the for loops I was writing would compile to the same for loops that the other guys were writing.

CoffeeScript currently makes up just over 1% of Airbnb's codebase. I expect that number to grow quite a bit over the next year. Here's the breakdown according to github: http://cl.ly/2A241Z2d2I2m2R211Q1t

[roopeshv]

also, the comparison of number of lines for coffeescript and javascript is usually misleading, because same logic/implementation in cs is usually(or, always) smaller than the js version.

How much functionality, if you can make a guess, would you say is there in the codebase in cs?

[_harry]

All of the http://m.airbnb.com functionality is in CoffeeScript.