Development environment for custom widgets

I love HABPanel and I would like to continue extending my HABPanel with more custom widgets. However, I find the development cycle really inconvenient. I have a git repo with the angularjs html that I modify and then I manually copy it to the widget (click on edit, paste, click on run). Then I figure that I mistyped a css class name and I have to do all of it again.

This is quite cumbersome. Is there any easier/faster way to test my code? Some kind of angularjs development enviroment that I could set up easily? It doesn’t need to hook to the real OpenHAB instance or get real values. It would be great if we could have e.g. a big map/dictionary with all the needed OpenHAB items and their current state. Nothing fancy.

How do you guys do it? Could anyone share a template github repo with your basic development environment?