What happens when you write to a nil map vs an empty map?
Writing to a nil map causes a runtime panic. Reading from a nil map returns the zero value safely. An empty map initialized with make() is safe for both reads and writes.
Nil map vs empty map
Best practices
Always initialize maps in struct constructors — do not rely on callers to initialize
Use make(map[K]V, hint) with a size hint when the approximate number of entries is known
Deleting from a nil map does NOT panic — delete() on nil map is a no-op
len() on a nil map returns 0 without panic
Range over a nil map produces zero iterations without panic