Whenever anyone calls something an [adjective]-ass [noun], move the hyphen one word to the right.
$ npm install xkcd-37
var xkcd37 = require('xkcd-37')
xkcd37('Man, that\'s a sweet-ass car')
//=> 'Man, that\'s a sweet ass-car'
Use a double backslash to not parse that part of the string.
var xkcd37 = require('xkcd-37')
xkcd37('Man, that\'s a sweet\\-ass car')
//=> 'Man, that\'s a sweet-ass car'