There’s a lot of buzz about Steve Yegge’s “port” of Rails to JavaScript, and Steve has now provided (in his funny, self-deprecating style) the background of how it came to be. He doesn’t quite say it explicitly in this post, but I think it reveals that the “Next Big Language” he has been hinting at is JavaScript.

I (mostly) agree:

JavaScript is in nearly every browser, including tiny ones (like the one in my BlackBerry Pearl). It may be the single most widely available language today.

Because of the above, an enormous population of JavaScript programmers (though sometimes of dubious skill) has emerged.

Starting with Java 6 it’s “in the box” there also. To me, this makes it the likely winner, by a wide margin, for a dynamic language to be used at Java shops or inside Java projects. Being “in the box” is a powerful advantage, one which the many other contenders will have a hard time overcoming.

Adobe’s new JavaScript virtual machine implementation, which they handed over to Mozilla as “Tamarin”, sounds like it will boost JavaScript performance great, making it good enough for a very wide variety of projects.

JavasScript uses curly braces, like the last few Big Languages.

Like Java, C, C++, etc., JavaScript has specs and multiple competing, complete, current, high quality implementations. This, to me, is a big advantage over Ruby, Python, and other currently popular dynamic languages. Of course there is plenty of room in the industry for these language to thrive also, I am not saying any of them will go away; we use Python with great results and expect to keep doing so.

Mark Volkmann initially thought I was nuts to predict JavaScript as a winner but came around a few month later (and said so in a user group talk).

In a project at work, we’d adopted JavaScript as our plugin extension language for user-customizable rules (billing rules, etc.). I’d have chosen Lua (as I did for another project), but there are at least 1000x as many JavaScript programs out there. So far it has worked very well. If we had it to do over we might implement far more of the project in JavaScript.

However, there are a few reasons why I only “mostly” agree:

First, with JavaScript there isn’t a good way to avoid shipping source code. Sure, you an obfuscate JavaScript with various tools, but the results remains far for amenable to readable-source recovery than in a more traditionally compiled language. For open source projects this is no big deal, but there are also many worthwhile businesses and projects which depend on proprietary, not open software (including most of our projects), and it’s not year clear that obfuscation is sufficient protection. (Update in reply to a comment below: This matters even for server-side software, because some of us create and sell software products for other people to run on their servers.)

Second, at the moment JavaScript appears to lack a module system, without which it’s painful to build large systems. I expect an upcoming language version will address this.