Introducing a mixin class that implements a toJsonDelta() method that serializes the object to a JSON map of values of the changes in the object.

Usage

final person = Person("John", "Doe", 30);
person.lastName = "Smith";
person.age = 31;
final delta = person.toJsonDelta(); // {"lastName": "Smith", "age": 31}

Implement in your models

class Person extends JsonSerializable with JsonDelta {
  String firstName;
  String lastName;
  int age;

  Person({
    required this.firstName,
    required this.lastName,
    required this.age,
  }) {
    saveJsonDeltaState();
  }

  @override
  Map<String, dynamic> toJson() {
    return {
      'firstName': firstName,
      'lastName': lastName,
      'age': age,
    };
  }
}

Additional information

This package is compatible with json_serializable which facilitates your generation of JSON.