This chapter will look at extending Office and Google Apps using HTML web apps that run on the client and orchestrate server-side activities.
Add-ons came to Google Drive in 2014. In Chapter 10, we used add-ons in the context of writing container-bound apps associated with a particular doc, sheet, or form. Add-ons allow these kinds of extensions to be published in a store and installed by a user so that they are available for all of the user’s documents.
Coding add-ons is not much different from writing
HtmlService custom menu extensions, although the process of publishing them is complicated.
Excel users might be confused by the term add-ins, as it can also mean a companion workbook containing VBA code that can be executed by the main workbook, a COM add-in, or a VSTO add-in managed through the app’s add-in manager. A little like a library in Apps Script, an add-in is one method used to distribute useful extension code for general use.
At first glance, add-ons and add-ins seem very much alike:
Both run on the client and access data from the document on which they are operating. ...