This will make upgrading + bugfixing much easier and reduce duplicated code. To merge Docs and Slides, I imagine you probably want to have a shared helper library that calls into IntegratedApp or takes an IntegratedApp as an argument (I started this in the Slides js but never did much with it). Clasp push/pull should then hopefully auto sync the library to the extensions themselves.
This will make upgrading + bugfixing much easier and reduce duplicated code. To merge Docs and Slides, I imagine you probably want to have a shared helper library that calls into IntegratedApp or takes an IntegratedApp as an argument (I started this in the Slides js but never did much with it). Clasp push/pull should then hopefully auto sync the library to the extensions themselves.