Wordpress has the function wp_localize_scripts for translation, but the strings passed to it have to be hard-coded. Until you parse the .js-files and scan for occurrences of _e() with a fast regexp, and localize them with the data using the Wordpress _e-function to localize from a .po file.
Note. Your po-file has to include strings from javascript files. To do this in Poedit, see
http://stackoverflow.com/questions/16557327/how-to-generate-po-file-from-js-file-using-poedit.