Scala.js - Write in Scala for the browser

Now, having seen the talk at Scala days here are a few notes/thoughts:

This is currently the result of 4 months worth of work, and Sébastien Doeraene, the author of the slides and the code there-in, is going to be working on it at EPFL for the next 4 years or so for his doctorate.

This is being done by replacing the backend portions of the Scala compiler that emit java bytecode with ones that emit javascript.

When the slide showing that it is 16MB came up everyone laughed and the author acknowledged how large a number this is. It is the result of having to bring in the entire the Scala standard lib. He is planning to work on ways of cutting this number down.

At the end of talk Martin Odersky commented from the audience that this is an attempt by the EPFL at making Scala useable for large webapp development. If it proves successful more resources will put towards supporting it.

I plan to try this out for internal sites used by my company. Currently we split and then have to duplicate a lot of our code between Scala / Javascript. Scala for the server software, Javascript for frontends which are webapps. I haven't had time since I got back to do much more than clone the git repo.

For work and anything I would want to put on a web site it is more practical to write javascript and when I've had time for my own projects I've enjoyed scala.

For me this is a great direction. The idea that I'd suddenly replace my javascript is silly. But being able to pull in things I'm familiar with from both into the same prototype (and at the same layer) of something and debug it all in the debugger I'm most familiar with (and with correct code line references!) is awesome.

Similarly, for someone who is learning scala and doesn't have/want java+IDE experience, this could lead to learning scala as a language with much less overhead and/or while learning a more useful combination of debugger and editor.

I think the overly negative comments come from those who view javascript as the "problem" that every new way to integrate languages with it must have been designed to tackle. Since every language has trade-offs, there is always ample criticism available from that vantage point...

Quick comment from the author: #1 has already been addressed by emitting Source Maps. With a supporting browser, you can debug your Scala.js application easily. You get positions in the original source code, breakpoints in the original source code, stack traces in the original source code, etc.