Sweet! And since you get to pick your implementation for server-side work, you don't have to remain in the IE ghetto. But, obviously, I haven't been following JavaScript all that closely.

I guess they had to use a different keyword instead of var (much like Perl introduced my because local already meant something strange in Perl 4, and for sort of the same purpose...though my became the new right way to declare variables anywhere, since the goal is always to get smaller scope for variables, and it doesn't look like that's the right idea with let).

JavaScript still doesn't have namespaces or a package/module concept, though (right?), so it seems like there'd still be some pain points in building large modular software. Of course, it's a pretty flexible language, and I've seen some interesting usage of closures to replicate namespaces and packages, so I guess standardizing on a library that provides those facilities is all that's really needed.