Extending JavaScript with inline unit tests

2013-11-09T20:56:57.000Z

I’ve been checking out Pyret, the new language from the same guys that made

Add code coverage to your Node.js projects

2013-06-19T19:13:00.000Z

Note: This blog post is inspired on Xavier Seignard’s blog post. He gives a longer introduction on it, and integrates it together with Sonar. You should check it out.

Code coverage is convenient to get an overview of how well-tested your program is. I’m going to show you how to set up code coverage using Mocha, Istanbul and LCOV in two easy steps.

Virtual list in vanilla JavaScript

2013-05-12T19:20:28.000Z

Let’s say you need to show a scrolling list with millions of rows, or even a reasonably big list with visually complex rows, each one composed by several DOM elements or CSS3 effects.

If you try to render this the naive way, for example by appending rows into a DOM container with the CSS overflow property set to scroll (or auto), you will most likely run into performance issues. This is because all the items in the list are cached, thus your memory consumption will certainly go up, and since all the DOM nodes composing the rows of the list are appended in the document, the browser is trying to properly render them all making your CPU pretty busy as you scroll. If these rows change any style say, on hover, you will trigger a reflow and the experience will be even more sluggish.

Implement cursor-swiping in half an afternoon

2013-02-21T13:21:20.000Z

If you haven’t seen it yet, I suggest that you take a look at this concept video that made the rounds on the internet some months

The promise of Firefox OS

2013-02-09T18:57:30.000Z

“But how is it going to beat Android or iOS?”

That’s the reaction many people have when I tell them that I am working on Firefox OS, the new mobile operating system from Mozilla. It is a logical reaction. After all, we live in times where every major software company and its mother is releasing a mobile platform, struggling to lure developers into their new proprietary environment, APIs, libraries, etc. And indeed, many of these companies barely make it or don’t make it at all.

But Firefox OS will not be directly battling against other mobile platforms. Its main objective is to change the way the world develops mobile apps, and even in the unlikely event that Firefox OS itself disappears in the process, if web-apps become mainstream, it will have succeeded.

Moving on

2013-01-29T19:04:18.000Z

A little bit more than two years ago I was sitting on a meeting room, listening to Ruben Daniels and Rik Arends, the two founders of the company I was considering to join, Cloud9 IDE. These were two of the smartest, most inspiring people I’ve met, and they were working hard on a ground-breaking concept: a full-fledged development environment that run in the browser, and in the cloud. At the time, that sounded wildly adventurous, to say the least. But the challenges were so many, the concept so revolutionary and the people so inspiring that I joined the company two weeks after that conversation.

Nodejsconf in Italy

2012-11-12T19:08:36.000Z

Last weekend I was at the Node.js conference in Brescia, Italy. Like every year the organizers

My talk at DynCon 2011

2011-04-04T17:09:04.000Z

The video with my talk about Cloud9 IDE at DynCon 2011 is

Dynamically generating MIDI in JavaScript

2010-11-08T21:09:38.000Z

Last weekend I open-sourced a small side project consisting of a JavaScript library that

Writing a JavaScript interpreter for DBN using PEG.js and canvas (Part II)

2010-08-20T19:32:04.000Z

In this article I build an interpreter for the DBN language from the parsed AST generated by the grammar we defined

Writing a JavaScript interpreter for DBN using PEG.js and canvas (Part I)

2010-08-03T06:03:43.000Z

In this first part of the article, I will define a grammar for DBN (Design By Numbers) and generate a parser for it that

GitHub in Catalan

2010-07-28T19:34:19.000Z

This is awesome. From now on, Catalan users of GitHub can use the website in their native language. Thanks to the Github team initiative

Blog running on Jekyll now

2010-04-13T19:35:50.000Z

That’s right, I couldn’t resist switching to Jekyll. I feel so free now! For those who

ABN Amro to Wesabe script

2009-02-25T21:37:40.000Z

Wesabe is a great service. And a very big part of its greatness resides in the fact that it

YQL mashup with GWT

2008-11-16T21:40:04.000Z

Yahoo came up with YQL a few weeks ago, and I think it is a very interesting idea. It is basically a SQL-like language that allows developers to retrieve structured data from multiple Yahoo web services without having to deal with each service particularities; developers can query any service in a generic way, just like they would do retrieving rows and columns from a SQL database.

Solitaire Encryption Algorithm implementation in F#

2008-10-13T19:45:48.000Z

I first read about the Solitaire algorithm in the novel Cryptonomicon, by Neal Stephenson. Being a geeky kid fascinated by computers I thought that it was a brilliant idea, but my curiosity didn’t go so far as to make me write an implementation of it (you can find a perl version in the book, which by the way I consider to be another great way to encrypt information).

Solitaire is a Stream Cipher created by Bruce Schneier and designed to be used with only a deck of cards. No electronic devices are needed and its security is intended to be of military-strength; that means that even if the way to generate/decipher messages is manual and might look a bit rudimentary, ideally not even the most powerful government could ever decipher a message generated with Solitaire (although some potential flaws have been reported).

So after playing with F# lately, I decided to write some non-trivial code in order to see how it suits my coding style and habits, and yet another naive implementation of this curious crypto-algorithm was born.

Nth attempt

2008-10-08T19:50:36.000Z

Yes, I am blogging again. But this time I have a plan. My last blog tried to cover too many things, from my life abroad, to ramblings on

Sergi Mansilla

Refactoring in Go: Using reflection

Refactoring in Go: goroutine concurrency

React patterns: Privileged Content

Real World Observables

Firefox disabled my extensions

Making geolocation work on Geeksphone devices

Extending JavaScript with inline unit tests

Add code coverage to your Node.js projects

Virtual list in vanilla JavaScript

Implement cursor-swiping in half an afternoon

The promise of Firefox OS

Moving on

Nodejsconf in Italy

My talk at DynCon 2011

Dynamically generating MIDI in JavaScript

Writing a JavaScript interpreter for DBN using PEG.js and canvas (Part II)

Writing a JavaScript interpreter for DBN using PEG.js and canvas (Part I)

GitHub in Catalan

Blog running on Jekyll now

ABN Amro to Wesabe script

YQL mashup with GWT

Solitaire Encryption Algorithm implementation in F#

Nth attempt