SAPUI5 provides two type of source code:
- The minimized such as Button-dbg.js, which is used for run time
- The debug version such as Button-dbg.js, which contain the human being readable source code.
If we want to study the source code, we only need to add the debug version to the project. But as there are so many source code, it is very difficult to just add the debug version. In order to solve this problem, I create a simple tool for it.
Solution:
( Under Linux, it is very easy, just use the find command can find out all the *dbg.js and copy it to another folder. As most of us work on Windows, so it come out this blog 
)
In the windows command window, go to the directory contain the sapui5 source code, and type command
dir *dbg.js /s /w
The output like
Directory of C:\src\git_ws\resources\sap\m
ActionListItem-dbg.js ActionListItemRenderer-dbg.js ActionSelect-dbg.js
ActionSelectRenderer-dbg.js ActionSheet-dbg.js ActionSheetRenderer-dbg.js
App-dbg.js AppRenderer-dbg.js Bar-dbg.js
BarRenderer-dbg.js BusyDialog-dbg.js BusyDialogRenderer-dbg.js
The output will list the directory, then list all the files under that directory. So we can create a tool which will analyze the output, then generate the command which can copy the debug version file into another folder. Then we can import all the files under that folder.
Tool link and usage
Just open Copy UI5 Source
It looks like