faster

code/__HELPERS/lists.dm

@@ -87,6 +87,13 @@
 		if(!typecache[A.type])
 			. += A
 
+/proc/typecache_filter_multi_list_exclusion(list/atoms, list/typecache_include, list/typecache_exclude)
+	. = list()
+	for(var/thing in atoms)
+		var/atom/A = thing
+		if(typecache_include[A.type] && !typecache_exclude[A.type])
+			. += A
+
 //Like typesof() or subtypesof(), but returns a typecache instead of a list
 /proc/typecacheof(path, ignore_root_path)
 	if(ispath(path))

code/modules/power/tesla/energy_ball.dm

@@ -171,7 +171,7 @@
 										/obj/machinery/the_singularitygen/tesla))
 
 
-	for(var/A in typecache_filter_list_reverse(typecache_filter_list(oview(source, zap_range+2), things_to_shock), blacklisted_tesla_types))
+	for(var/A in typecache_filter_multi_list_exclusion(oview(source, zap_range+2), things_to_shock, blacklisted_tesla_types))
 		if(istype(A, /obj/machinery/power/tesla_coil))
 			var/dist = get_dist(source, A)
 			var/obj/machinery/power/tesla_coil/C = A