What will replace Script Links / Script Blocks in the SharePoint Framework? (e.g. for mega menus)

[Brent Ellis]

I have a requirement to perform an action on EVERY page in a site collection.  Examples of this include injecting Javascript, CSS, HTML for things like mega menus, 3rd party analytics trackers, custom branding etc.

Since usercustomactions/scriptlinks/scriptblocks and master pages are essentially "going away", how will we do this going forward in the SharePoint Framework?

The requirement is to set it once for the entire Site Collection, and not have to do it library by page by list by site by whatever.

This has been a supported practice for years and we have build many solutions that will essentially be lost as we start to adopt the new "modern" experiences. 

[#2]

So far nothing has been mentioned or announced regarding this capability. I'm pretty sure the PG is looking into it and it's fair to expect more information about it as the SharePoint Framework evolves.

[#3]

Just trying to keep it on the radar -- great discussion on the Yammer group that will soon be gone :(

this is a valid need that no way ahead has been addressed and is limiting our organizations ability to take advantage of new features

losing a capability like this will severely damage the user experience in our organization as we have used supported methods to build a very detailed navigation structure which doesnt work in modern UI at all