One of the questions we frequently got from customers was on how to handle 404 / 500 pages in the SPA editor.
Unfortunately we could not give a good answer, and it required a lot of hacking to make it work.
Thats why just now, we updated the spa page model manager to support handling 404 / 500 pages!
It works like this:
Page Request is made and ACS AEM error handler catches it.
Client tries to fetch a model JSON but get's a 404 error in return.
Client now will take the error page root (given as meta property) and use the status code to make a new request.
Presuming the page exists, the authored error page model JSON is injected as requested path.
The error page is displayed.
Check out the repository providing a demo: