Interesting idea, which could be built on top of the Binary AST.
I would personally prefer it being handled transparently by the middleware or the cdn, which would neatly separate the responsibilities between the browser, the cache+compressor and the http server.
Anyway, one of the reasons this project is only about a file format is so that we can have this kind of conversation about what the browsers and other tools can do once we have with a compressed JS file.
One of my fears about doing this at the CDN level is that now introducing a new syntax feature means you need the browser to support it AND the version of the Binary AST compiler on your CDN. Imagine using a new JS keyword and all of a sudden all your code gets slower because its a syntax error at the CDN level. It would just slower the rate of introduction of new syntax features I think by needing a lot more coordination: its already a bit messy with different browsers having different support, now caniuse.com may need to include CDN's too.
I would personally prefer it being handled transparently by the middleware or the cdn, which would neatly separate the responsibilities between the browser, the cache+compressor and the http server.
Anyway, one of the reasons this project is only about a file format is so that we can have this kind of conversation about what the browsers and other tools can do once we have with a compressed JS file.