lastbar only with historical trigger(barstate.islast[yoxxx]

Since i found nothing for this special need, here is my template or snippet for customization..

Case: If i want an optical hint for an exceeding indicator - as a visual alarm feature or similar -
it can be very disturbing when the symbol appears for all that cases on the chart.
Solution: The script calculates the condition only for the last bar on the right - which isnt trivial, for on principal pine calculates every value for each bar presently growing.

I declared as comments within the code what special aspects have to be kept on focus occasionally by doing so.

Hope it's helpful, cheers
yoxxx