Nullable<T> class

A class that represents a nullable value It is used to wrap a value that can be null and provide a way to handle null values in a type-safe way Example in copyWith:

class Person {
  final String name;
  final int? age;

  Person({required this.name, this.age});

  Person copyWith({String? name, Nullable<int>? age}) {
    return Person(name: name ?? this.name, age: age?.value ?? this.age);
  }
}

final person = Person(name: "John", age: 30);
final personWithUnmodifiedAge = person.copyWith(age: null);
print(personWithUnmodifiedAge.age); // 30
final personWithModifiedAge = person.copyWith(age: Nullable(value: 40));
print(personWithModifiedAge.age); // 40
final personWithNullifiedAge = person.copyWith(age: Nullable(value: null));
print(personWithNullifiedAge.age); // null