asMap function
Implementation
Map<String, dynamic> asMap(Map<String, dynamic>? json, String key, {Map<String, dynamic>? defaultValue}) {
if (json == null || !json.containsKey(key)) return defaultValue ?? <String, dynamic>{};
var value = json[key];
if (value == null) return defaultValue ?? <String, dynamic>{};
if (value is Map<String, dynamic>) return value;
return defaultValue ?? <String, dynamic>{};
}