apn_json2model Pub Version

Command line tool for generating Dart models (json_serializable) from Json file.

inspired by json_model.

based of the json_to_model



Null safety
immutable classes
copyWith generation
clone and deepclone
nested json classes
enum support


on pubspec.yaml

  apn_json2model: ^2.2.0

install using pub get command or if you using dart vscode/android studio, you can use install option.

What does this library do

Command line tool to convert .json files into immutable .dart models.

Get started

The command will run through your json files and find possible type, variable name, import uri, decorator and class name, and will write it into the templates.

Create/copy .json files into ./jsons/(default) on root of your project, and run flutter pub run apn_json2model.


Input Consider this files named product.json and employee.json


  "id": "123",
  "caseId?": "123",
  "startDate?": "2020-08-08",
  "endDate?": "2020-10-10",
  "placementDescription?": "Description string"


  "id": "123",
  "displayName?": "Jan Jansen",
  "@ignore products?": "$[]product"

Output This will generate this product.dart and employee.dart


import 'package:flutter/foundation.dart';

class Product {
  const Product({
    required this.id,

  final String id;
  final String? caseId;
  final String? startDate;
  final String? endDate;
  final String? placementDescription;

  factory Product.fromJson(Map<String,dynamic> json) => Product(
    id: json['id'] as String,
    caseId: json['caseId'] != null ? json['caseId'] as String : null,
    startDate: json['startDate'] != null ? json['startDate'] as String : null,
    endDate: json['endDate'] != null ? json['endDate'] as String : null,
    placementDescription: json['placementDescription'] != null ? json['placementDescription'] as String : null
  Map<String, dynamic> toJson() => {
    'id': id,
    'caseId': caseId,
    'startDate': startDate,
    'endDate': endDate,
    'placementDescription': placementDescription

  Product clone() => Product(
    id: id,
    caseId: caseId,
    startDate: startDate,
    endDate: endDate,
    placementDescription: placementDescription

  Product copyWith({
    String? id,
    String? caseId,
    String? startDate,
    String? endDate,
    String? placementDescription
  }) => Product(
    id: id ?? this.id,
    caseId: caseId ?? this.caseId,
    startDate: startDate ?? this.startDate,
    endDate: endDate ?? this.endDate,
    placementDescription: placementDescription ?? this.placementDescription,

  bool operator ==(Object other) => identical(this, other) 
    || other is Product && id == other.id && caseId == other.caseId && startDate == other.startDate && endDate == other.endDate && placementDescription == other.placementDescription;

  int get hashCode => id.hashCode ^ caseId.hashCode ^ startDate.hashCode ^ endDate.hashCode ^ placementDescription.hashCode;


import 'package:flutter/foundation.dart';
import 'product.dart';

class Employee {

  const Employee({
    required this.id,

  final String id;
  final String? displayName;
  final List<Product>? products;

  factory Employee.fromJson(Map<String,dynamic> json) => Employee(
    id: json['id'] as String,
    displayName: json['displayName'] != null ? json['displayName'] as String : null

  Map<String, dynamic> toJson() => {
    'id': id,
    'displayName': displayName

  Employee clone() => Employee(
    id: id,
    displayName: displayName,
    products: products?.map((e) => e.clone()).toList()

  Employee copyWith({
    String? id,
    String? displayName,
    List<Product>? products
  }) => Employee(
    id: id ?? this.id,
    displayName: displayName ?? this.displayName,
    products: products ?? this.products,

  bool operator ==(Object other) => identical(this, other)
    || other is Employee && id == other.id
    && displayName == other.displayName
    && products == other.products;

  int get hashCode => id.hashCode ^
    displayName.hashCode ^

Input Consider this file named location.json

    "locationId?": 93,
    "locationTypeId?": "1234",
    "updatedAt": "@datetime",
    "name?": "Lunet 10a, Veenendaal",
    "confidential?": false,
    "point?": {
        "longitude": 58.1234,
        "latitude": 12.123

Output This will generate this location.dart

import 'package:flutter/foundation.dart';

class Location {

  const Location({
    required this.updatedAt,

  final int? locationId;
  final String? locationTypeId;
  final DateTime updatedAt;
  final String? name;
  final bool? confidential;
    get locationLocationTypeEnum => _locationLocationTypeEnumValues.map[locationType]!;
  final String? locationType;
  final Point? point;

  factory Location.fromJson(Map<String,dynamic> json) => Location(
    locationId: json['locationId'] != null ? json['locationId'] as int : null,
    locationTypeId: json['locationTypeId'] != null ? json['locationTypeId'] as String : null,
    updatedAt: DateTime.parse(json['updatedAt'] as String),
    name: json['name'] != null ? json['name'] as String : null,
    confidential: json['confidential'] != null ? json['confidential'] as bool : null,
    locationType: json['locationType'] != null ? json['locationType'] as String : null,
    point: json['point'] != null ? Point.fromJson(json['point'] as Map<String, dynamic>) : null

  Map<String, dynamic> toJson() => {
    'locationId': locationId,
    'locationTypeId': locationTypeId,
    'updatedAt': updatedAt.toIso8601String(),
    'name': name,
    'confidential': confidential,
    'locationType': _locationLocationTypeEnumValues.reverse[locationType],
    'point': point?.toJson()

  Location clone() => Location(
    locationId: locationId,
    locationTypeId: locationTypeId,
    updatedAt: updatedAt,
    name: name,
    confidential: confidential,
    locationType: locationType,
    point: point?.clone()

  Location copyWith({
    int? locationId,
    String? locationTypeId,
    DateTime? updatedAt,
    String? name,
    bool? confidential,
    String? locationType,
    Point? point
  }) => Location(
    locationId: locationId ?? this.locationId,
    locationTypeId: locationTypeId ?? this.locationTypeId,
    updatedAt: updatedAt ?? this.updatedAt,
    name: name ?? this.name,
    confidential: confidential ?? this.confidential,
    locationType: locationType ?? this.locationType,
    point: point ?? this.point,

  bool operator ==(Object other) => identical(this, other)
    || other is Location && locationId == other.locationId && locationTypeId == other.locationTypeId && updatedAt == other.updatedAt && name == other.name && confidential == other.confidential && locationType == other.locationType && point == other.point;

  int get hashCode => locationId.hashCode ^ locationTypeId.hashCode ^ updatedAt.hashCode ^ name.hashCode ^ confidential.hashCode ^ locationType.hashCode ^ point.hashCode;

enum LocationLocationTypeEnum { INSIDE, OUTSIDE, CLIENT, HOME, ROOM, UNKNOWN }

extension LocationLocationTypeEnumEx on LocationLocationTypeEnum{
  String? get value => _locationLocationTypeEnumValues.reverse[this];

final _locationLocationTypeEnumValues = _LocationLocationTypeEnumConverter({
  'INSIDE': LocationLocationTypeEnum.INSIDE,
  'OUTSIDE': LocationLocationTypeEnum.OUTSIDE,
  'CLIENT': LocationLocationTypeEnum.CLIENT,
  'HOME': LocationLocationTypeEnum.HOME,
  'ROOM': LocationLocationTypeEnum.ROOM,
  'UNKNOWN': LocationLocationTypeEnum.UNKNOWN,

class _LocationLocationTypeEnumConverter<String, O> {
  final Map<String, O> map;
  Map<O, String>? reverseMap;


  Map<O, String> get reverse => reverseMap ??= map.map((k, v) => MapEntry(v, k));

class Point {

  const Point({
    required this.longitude,
    required this.latitude,

  final double longitude;
  final double latitude;

  factory Point.fromJson(Map<String,dynamic> json) => Point(
    longitude: json['longitude'] as double,
    latitude: json['latitude'] as double

  Map<String, dynamic> toJson() => {
    'longitude': longitude,
    'latitude': latitude

  Point clone() => Point(
    longitude: longitude,
    latitude: latitude

  Point copyWith({
    double? longitude,
    double? latitude
  }) => Point(
    longitude: longitude ?? this.longitude,
    latitude: latitude ?? this.latitude,

  bool operator ==(Object other) => identical(this, other)
    || other is Point && longitude == other.longitude && latitude == other.latitude;

  int get hashCode => longitude.hashCode ^ latitude.hashCode;

Getting started

  1. Create a directory jsons(default) at root of your project
  2. Put all or Create json files inside jsons directory
  3. run pub run apn_json2model. or flutter packages pub run apn_json2model flutter project


this package will read .json file, and generate .dart file, asign the type of the value as variable type and key as the variable name.

DescriptionExpressionInput (Example)Output(declaration)Output(import)
declare type depends on the json value{...:any type}{"id": 1, "message":"hello world"},int id;
String message;
import model and asign type{...:"$value"}{"auth":"$user"}User auth;import 'user.dart'
import from path{...:"$../pathto/value"}{"price":"$../product/price"}Price price;import '../product/price.dart'
asign list of type and import (can also be recursive){...:"$[]value"}{"addreses":"$[]address"}List<Address> addreses;import 'address.dart'
import other library(input value can be array){"@import":...}{"@import":"package:otherlibrary/otherlibrary.dart"}import 'package:otherlibrary/otherlibrary.dart'
Datetime type{...:"@datetime"}{"createdAt": "@datetime:2020-02-15T15:47:51.742Z"}DateTime createdAt;
Enum type{...:"@enum:(folowed by enum separated by ',')"}{"@import":"@enum:admin,app_user,normal"}enum UserTypeEnum { Admin, AppUser, Normal }
Enum type with values {...:"@enum:(folowed by enum separated by ',')"}{"@import":"@enum:admin(0),app_user(1),normal(2)"}enum UserTypeEnum { Admin, AppUser, Normal }