How to remove records in store when they are not in server anymore

I have application which may lost connection with server for days and when it finally reconnect some record exist in store didn’t exist in server any more.

I try to fix it but can’t get any where.

store.findall didn’t seems to have option to delete record not returned by server.

I can’t find ways to chain store.unloadAll and store.findAll without have the blank state take effect on the screen and cause flickering

I also can’t find out how to get what actually returned by server without go completely manual (make my own ajax calls,which won’t scale obviously)

I am wondering what everyone else is using in this situation

Thanks for any help