JSON to Dart Class (Flutter)

{
  "id": 1024,
  "name": "Ada Lovelace",
  "email": "ada@example.com",
  "active": true,
  "score": 98.5,
  "tags": [
    "admin",
    "beta"
  ],
  "address": {
    "city": "London",
    "postcode": "NW1 6XE"
  }
}

// To parse this JSON data, do
//
//     final user = userFromJson(jsonString);

import 'dart:convert';

User userFromJson(String str) => User.fromJson(json.decode(str));

String userToJson(User data) => json.encode(data.toJson());

class User {
    final int id;
    final String name;
    final String email;
    final bool active;
    final double score;
    final List<String> tags;
    final Address address;

    User({
        required this.id,
        required this.name,
        required this.email,
        required this.active,
        required this.score,
        required this.tags,
        required this.address,
    });

    factory User.fromJson(Map<String, dynamic> json) => User(
        id: json["id"],
        name: json["name"],
        email: json["email"],
        active: json["active"],
        score: json["score"]?.toDouble(),
        tags: List<String>.from(json["tags"].map((x) => x)),
        address: Address.fromJson(json["address"]),
    );

    Map<String, dynamic> toJson() => {
        "id": id,
        "name": name,
        "email": email,
        "active": active,
        "score": score,
        "tags": List<dynamic>.from(tags.map((x) => x)),
        "address": address.toJson(),
    };
}

class Address {
    final String city;
    final String postcode;

    Address({
        required this.city,
        required this.postcode,
    });

    factory Address.fromJson(Map<String, dynamic> json) => Address(
        city: json["city"],
        postcode: json["postcode"],
    );

    Map<String, dynamic> toJson() => {
        "city": city,
        "postcode": postcode,
    };
}