isMapOfStringKeys function
Returns true
if map
has String keys.
Implementation
bool isMapOfStringKeys(Map? map) {
if (map == null) return false;
if (map is Map<String, String>) return true;
if (map is Map<String, dynamic>) return true;
if (map.isEmpty) return false;
if (listNotMatchesAll(map.keys, (k) => (k is String))) return false;
return true;
}