class UserModel { final String uid; final String name; final String email; final String createdAt; UserModel({ required this.uid, required this.name, required this.email, required this.createdAt, }); factory UserModel.fromMap(Map json) { return UserModel( uid: json['uid'] ?? '', name: json['name'] ?? '', email: json['email'] ?? '', createdAt: json['created_at'] ?? '', ); } Map toMap() { return {'uid': uid, 'name': name, 'email': email, 'created_at': createdAt}; } }