stringMap function
Reads a {"key": "value"} map, dropping any non-string value.
Implementation
Map<String, String> stringMap(Map<String, dynamic> json, String key) {
final value = json[key];
if (value is! Map) return const {};
return {
for (final entry in value.entries)
if (entry.key is String && entry.value is String)
entry.key as String: entry.value as String,
};
}