Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The NotRestoredReasonDetails interface of the Performance API represents a single reason why a navigated page was blocked from using the back/forward cache (bfcache).
An array of NotRestoredReasonDetails objects can be accessed via the NotRestoredReasons.reasons property.
reason Read only A string describing a reason that the page was blocked from using the back/forward cache.
toJSON() A serializer; returns a JSON representation of the NotRestoredReasonDetails object.
See Monitoring bfcache blocking reasons for examples.