entity_id()
Syntax
entity_id(id)
Fetching entities either by their ID obtained via entity ~ 'id', which is
unique for a dimension and current world run, or by UUID, obtained via
entity ~ 'uuid'. It returns null if no such entity is found. Safer way to
‘store’ entities between calls, as missing entities will be returning null.
Both calls using UUID or numerical ID are O(1), but obviously using UUIDs
takes more memory and compute.