reactiveMap does not work with size/delete

I have noticed that

reactiveMap

reactiveMap

reactiveMap

reactiveMap does not trigger update on

delete

delete

delete

delete or when we "subscribe" using

size

size

size

size or

forEach

forEach

forEach

forEach method.
Most confusing for me is

delete

delete

delete

delete since if i use

has

has

has

has i expect that update will trigger signal, but this is not the case.

Is it expected behaviour ?