JS doesn't solve the client/server impedance mismatch at all. The JS community is struggling with designing libraries that work as well on the server as well as the client.
As Ryan (Node.js) has said, I see JS going the way of PHP. That's great and that it will attract certain kinds of coders and certain kinds of projects.
But setting programming back by a decade? Personally I find JS a much better foundation for learning FP principles than PHP - there's enough in there to guide people to the topics I've outlined above. In fact my interest in these topics arose from being a JS coder for 5 years!
"The JS community is struggling with designing libraries that work as well on the server as well as the client."
Disagree. YUI3 was a library written for the web, but it was so well designed that it took one YUI engineer hacking around for a few days to get it fully running in Node.js. Now, some awesome stuff is happening and it's an area of focus for the YUI team. http://express.davglass.com/
Mustache.js and Underscore.js are other examples of popular JS libraries that work great server-side right off the bat.
The main one left out is jQuery, and that is a library written primarily for DOM manipulation, which isn't really the point server-side (most of the time). Once JSDOM is a bit more mature, I'm certain you'll see jQuery become more popular server-side.
As Ryan (Node.js) has said, I see JS going the way of PHP. That's great and that it will attract certain kinds of coders and certain kinds of projects.
But setting programming back by a decade? Personally I find JS a much better foundation for learning FP principles than PHP - there's enough in there to guide people to the topics I've outlined above. In fact my interest in these topics arose from being a JS coder for 5 years!
JS is the gateway drug to the new future.