While working on CLJS-1722 I spotted two issues with pr-writer-ex-info:
1) if data or cause happen to be "false", they are skipped in printing
2) the code tries to mimic map printer
This patch fixes both issues. It turns out printing real info map yields exactly same string output and plays better with cljs-devtools printer (which newly sees real map instead of soup of strings and values).
For reference: pr-writer-ex-info was implemented in CLJS-983