I just participated in the 2nd annual 48-hour Node.JS Knockout competition together with James Halliday, Joshua Holbrook, and David Wee. Almost the same team as the last year. This year we called ourselves Replicants and we created a real-time code coverage heatmapping application called Heatwave!

If you like our app, please give us thumbs up, that will really help us out. You can vote for our app at Replicants team page.

Just for the record, here is a screenshot of our application (try it here):

Heatwave app.

So you can either paste the code snippet right on the site and run it and it will show live code heatmap as it runs.

Or you can upload your code via a web form and it will get stored on heatwave server and you'll get a unique url with your heatwave that you can share. Like this:

switch() rainbow

You can also use curl to upload your code. That's the smartest hackery I have seen. Idea by James Halliday. You can just do:

curl -sNT file.js heatwave.nodejitsu.com

And that will upload the code to the heatwave server and respond with info on how to see it. Like this:

$ curl -sNT foo.js heatwave.nodejitsu.com
Visit this site to run and manage the code:
    http://heatwave.nodejitsu.com/id/09306fa0

 To upload more files:
    curl -sNT file.js heatwave.nodejitsu.com/id/09306fa0/file.js

And with curl you can even upload multiple files to the same page, which is super neat.

We had really great team work. Josh, James and David hacked from Joyent and we communicated over IRC, just like the last year. Each of us had a separate github repo and we'd just pull from each other every now and then. That's about it.

The source code of heatwave is on github: heatwave source.

I'm looking forward to next year's node.js knockout.