cljs.reader/read-string speeds up by a factor of 2 on Firefox/Windows through this change without complicating the code.
(Other JS engines, including Firefox on Linux/Mac do not seem to be affected as significantly.)
Firefox on Windows
It would be nice to have a bit more information on this ticket as to what Google Closure does that's unnecessary or whether this path is actually a faithful port of Clojure behavior (copies the implementation of the EDN reader in these hot spots??). Finally the patch names David Frese, have they submitted a CA?
Comment made by: sperber
I believe the Google functions are too general, work on strings in addition to characters etc.
It's not clear to us though why only Firefox on Windows benefits.
(David Frese is a co-worker - yes, has submitted a CA.)