Yesterday I launched Bifocals.js, a node library for handling http responses.

It was my first big launch, and I learned a ton from it. Before I go into that, lets show some numbers.

  • Peaked at # 9 on Hacker News
  • 7,077 Page Views
  • 6,202 Unique Visitors
  • 56% United States
  • 70% Chrome
  • 48% Mac
  • 87% from
  • Avg. Visit Duration: 00:00:17

That visit duration is abysmal. Clearly the docs need to be improved.

I received the best discussion via Facebook, and then Hacker News. No one initially knew what the hell my library did. So I wrote up a new description, which will be added to the docs later.

Bifocals makes it incredibly easy to split your web page up into little tiny chunks. It might not be immediately obvious why this is useful, but it becomes slightly more clear with an understanding of the javascript event queue.

Any time an http request hits the server, it puts your callback into a queue. Node processes this queue in order. Every time you handle a callback for an http request, a database request, any socket or i/o in general, it uses this queue. Additionally, process.nextTick will add functions onto this queue.

If each of your callbacks operate quicker, it should allow improve the request time across your application. Each time a callback completes it releases control to another callback. With mix of pages that render at different speeds, faster requests should get out of the way while longer requests are still handling i/o.

Bifocals not only allows your view functions to be smaller, but it allows them to operate out of order. All of your views can start performing IO at the same time, and no matter which one finishes first bifocals will render the final output accurately.

When all of these techniques are put together, theoretically it should create a faster overall page speed across the entire site. (I hope to have real stats soon)

If you don’t need these benefits, bifocals offers two additional nice features.

  • It abstracts away template rendering to a simple workflow, and allows you to use any core render system you want.
  • It provides easy access to http status codes, and the strange http standard associated with them.

Hopefully this is a little more clear. Thanks to everyone who had comments, I have some cool new features coming soon.

Posted toTechon10/12/2012