You don't need the .min.map file for normal functionality. What the map file does is allow you to view the unminified version of the source code when you're loading the minified version, which is primarily useful in production.
http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/https://developers.google.com/chrome-developer-tools/docs/javascript-debugging#source-maps
It's perfectly safe to delete the file if you don't want it, it won't affect your code at all. The very worst case scenario is that you have Chrome Devtools open and see a 404 for the sourcemap file if you have sourcemaps enabled, but this won't happen for normal end users who don't have those dev tools open.
