mapMapOrNull<K, V> function
Implementation
Map<K, V>? mapMapOrNull<K, V>(Object? raw, MapEntryMapper<K, V> f) {
if (raw is! Map) return null;
final m = Map<dynamic, dynamic>.from(raw);
final out = <K, V>{};
for (final e in m.entries) {
final mapped = f(e.key, e.value);
if (mapped != null) out[mapped.key] = mapped.value;
}
return out;
}