Retrieve viewMode (preview or live) in backend

ViewMode can be retrieve in the frontend via https://www.wix.com/corvid/reference/wix-window.html#viewMode but there is no equivalent for the backend. This would be extremely useful to know since there are many difference between the 2 modes. Knowing that some code is running in preview we could mock operations (for testing or dev) and create a separation between dev environment and prod.