My translations weren't working, and I had to search through the source code of po2json to discover that I needed to use the 'jed1.x' setting rather than just 'jed'. Might be worth noting this in the documentation.
So just to be clear, I needed to run
jedInitJson = po2json.parse(window.PRELOAD.TRANSLATIONS, {format: 'jed1.x'})
instead of
jedInitJson = po2json.parse(window.PRELOAD.TRANSLATIONS, {format: 'jed'})
Thanks for the great library!