For me, one of the handy things about developing JS only apps is you can deploy the file to SP, get sneaky, open the js file from the file system and edit away, hitting save and refreshing the page.
I'm sure there are plenty of people who say this is a bad way to go about it, but hey, I find it very quick and easy when developing, obviously wouldn't do it live!, the only issue you face is remembering to copy back in your changes...which is a small price compared to hitting deploy all the time.
Now, can I do this with SharePoint Hosted App? I can't see where I can get to the deployed javascript file? I tried with SP designer to get to the app url, but it complains about SP designer not being support.
Just wondered if anyone else had a sneaky way in?
Seems a laborious process to keep deploying for everything little change.