main.dart

import 'dart:convert';

void main() {
 String object = '{"name": "hello"}';
  print(User.createInstance(jsonDecode(object)).name);
  String name = null;
  print(name);
}


class User{
  String name;
  String password;
  
  
  User({this.name, this.password});
  
 factory User.convertFromJson(Map<String, dynamic> jsonData){
    return User(
      name: jsonData['name'],
    );
  }
  
  static User createInstance(Map<String, dynamic> jsonData){
    User user = new User(name: jsonData['name']);
    return user;
  }
}