Possible of course, needs someone doing it :) For the highlighting part, it should be very easy, a mere matter of updating the keywords in *data/filetypes.javascript* to include the new ones. Grammar didn't change so much AFAIK, so it should be enough.
For the tagging part it'll be a little more works as it'll require updating the parser to really understand those new syntaxes, but it's something that will likely be done by Somebody at some point in the (probably not so distant) future. S/A https://github.com/universal-ctags/ctags/issues/780 --- Reply to this email directly or view it on GitHub: https://github.com/geany/geany/issues/934#issuecomment-192752805
