Dart Fusion


A tool for managing Dart or flutter projects. This contains cli, annotations, extensions, parsers and many more.



Dart Fusion Logo

Dart Fusion

A library that brings together a harmonious blend of essential tools, utilities, and components designed to supercharge my Dart projects.

Table of Contents


put this in your pubspec.yaml

      url: https://github.com/Nialixus/dart_fusion.git
      path: dart_fusion
      ref: v3.1.7

  # or import this one instead for flutter project
      url: https://github.com/Nialixus/dart_fusion.git
      path: dart_fusion_flutter
      ref: v3.1.7

also run this command in terminal

dart pub global activate --source git https://github.com/Nialixus/dart_fusion.git

Dart Fusion CLI Logo

Dart Fusion CLI

The Dart Fusion CLI is a command-line tool that provides a set of utilities to simplifies common tasks such as asset generation, model updates, and localization.

[!NOTE] This also can be achieved using DRunner


  • Asset Generation : Easily generate asset classes from asset directories, making it simple to access assets in your Dart project. To scan asset files and generate them into one dart class, run this command

    dart run dart_fusion asset

    And this is the list of available commands.

    -i, --inputInput directory of where assets took place.
    default to assets
    -o, --outputOutput file of generated asset class.
    default to lib/src/assets.dart
    -h, --helpPrint this usage information.
  • Model Updates : Update models by generating toJSON, fromJSON and copyWith based on given annotation. To update these models, run this command

    dart run dart_fusion model

    And this is the available commands.

    -i, --inputInput directory of the models.
    default to ""
    -h, --helpPrint this usage information.
  • Localization : Generate localization classes from JSON files, simplifying the process of managing free translations in your Dart applications.

    dart run dart_fusion localize

    List of the commands

    -i, --inputInput directory of where the JSON base translation took place.
    default to assets/translation/en.json
    -o, --outputGenerating JSON to easy_localization model
    --fromBase language used for translation
    default to en
    --toTargeted translation languages
    default to ["af","sq","am","ar","hy","as","ay","az","bm","eu","be","bn","bho","bs","bg","ca","ceb","zh-CN","zh","zh-TW","co","hr","cs","da","dv","doi","nl","en","eo","et","ee","fil","fi","fr","fy","gl","ka","de","el","gn","gu","ht","ha","haw","he","hi","hmn","hu","is","ig","ilo","id","ga","it","ja","jv","kn","kk","km","rw","gom","ko","kri","ku","ckb","ky","lo","la","lv","ln","lt","lg","lb","mk","mai","mg","ms","ml","mt","mi","mr","mni-Mtei","lus","mn","my","ne","no","ny","or","om","ps","fa","pl","pt","pa","qu","ro","ru","sm","sa","gd","nso","sr","st","sn","sd","si","sk","sl","so","es","su","sw","sv","tl","tg","ta","tt","te","th","ti","ts","tr","tk","ak","uk","ur","ug","uz","vi","cy","xh","yi","yo","zu"]
    -h, --helpPrint this usage information.

D Annotation Logo

D Annotations

D Annotations is a set of class used as an indicator for Dart Fusion CLI model generation


  • Model: Annotation of class as an indicator to generate a fromJSON, toJSON and copyWith inside the annotated class.
    class MyClass extends DModel {}
    // or you can annotate it like this
    @Model(immutable: true, copyWith: true, fromJSON: true, toJSON: true)
    class MyClass extends DModel {}

  • Variable: Annotation of variable inside a model class with @Model annotation.

    final DModel value;
    // or you can annotate it like this
    @Variable(name: 'd_model', toJSON: true, fromJSON: true)
    final DModel value;

    And when you run

    dart run dart_fusion model

    This will resulting something like this

    class MyClass extends DModel {
      const MyClass({required this.title, required this.value});
      @Variable(name: 'd_model', toJSON: true, fromJSON: true)
      final DModel value;
      final String title;
      MyClass copyWith({DModel? value, String? title}) {
        return MyClass(
          value: value ?? this.value,
          title: title ?? this.title,
      JSON get toJSON => {
        'd_model': value.toJSON,
        'title': title,
      static MyClass fromJSON(JSON value){
        return MyClass(
          value: DModel.fromJSON(value.of<JSON>('d_model'),
          title: value.of<String>('title'))

D Assertions

D Assertion is a set of assertion class used for performing assertions and validations.

  • Assert: The Assert class facilitates assertion checks based on boolean conditions. If the assertion fails, it throws an Exception with a provided message.

    int number = 1;
      number.isEven, // conditional needed in assertion checker
      'Number is not even!', // message if the conditional return false

  • Response: A specialized Assert class for handling response-related assertions.
    return (context) {
      final method = context.request.method;
        method == HttpMethod.post, // assertion checker
        'Invalid Method!', // message if the conditional return false
        statusCode: 405, // status code to send inside `ResponseException`

D Behavior

D Behavior is a custom scroll behavior for controlling the scrolling physics of scrollable widgets.


  behavior: DBehavior(
    physics: BouncingScrollPhysics()),
  child: ListView(),

D Builder

D Builder is a widget that builds its child using a custom builder function with optional data.


  data: {"name": "John", "age": 30},
  builder: (context, data) {
    final name = data.of<String>("name");
    final age = data.of<int>("age");
    return Text("My name is $name and I am $age years old.");

D Exceptions

D Exceptions is a set of exception class used in this library.

  • Type Exception: An exception caused by failing to parse Type.

    throw TypeException(
      message: 'Type is not available',

  • Response Exception: An exception containing Response value.
    throw ResponseException(
        response: Response(
          statusCode: 404,

D Extensions Logo

D Extensions

An extension collection of mostly used function in flutter project.

Number Extension

Extension on numeric types (int, double) to add utility methods for limiting values within a specified range.

  • Min : Limit the minimum number of the extended value.
    int min = 5.min(10);
    print(min); // 10
  • Max : Limit the maximum number of the extended value.
    double max = 100.0.max(10.0);
    print(max); // 10.0
  • Limit : Limit number of the extended value in a certain range.
    int number = 75.limit(0, 100);
    print(number); // 75

Integer Extension

Converts integer to a human-readable string representing bytes.

int bytes = 1048576;
String parse = bytes.toReadableBytes;
print(parse); // "1048.57 KB"

JSON Extension

Extension on the Map<String, dynamic> value.

  • Merge : Merging one JSON to another.
    JSON json = {"primary": "1", "secondary": "2"};
    JSON anotherJSON = {"primary": "10", "tertiary": "3"};
    print(json.merge(anotherJSON)); // {"primary": "10", "secondary": "2", "tertiary": "3"}
  • Of : Parse dynamic value in JSON to given Object with an optional onError fallback.
    JSON value = {"primary": "1"};
    String primary = value.of<String>("primary");
    print(primary); // "1"
    String secondary = value.of<String>("secondary", "No Data");
    print(secondary); // "No Data"
  • Maybe of : Parse dynamic value in JSON to given nullable Object.
    JSON value = {"primary": "1"};
    String? primary = value.maybeOf<String>("primary");
    print(primary); // "1"
    String? secondary = value.maybeOf<String>("secondary");
    print(secondary); // null

BuildContext Extension

A set of extension collection on BuildContext.

  • Theme : A shortcut for calling Theme.of(context).
    ThemeData theme = context.theme;
  • Color : A shortcut for calling Theme.of(context).colorScheme.
    ColorScheme color = context.color;
  • Text : A shortcut for calling Theme.of(context).textTheme.
    TextTheme text = context.text;
  • Query : A shortcut for calling MediaQuery.of(context).
    MediaQuery query = context.query;
  • Size : A shortcut for calling MediaQuery.sizeOf(context).
    Size suze = context.querySize;
  • Width : A shortcut for calling MediaQuery.sizeOf(context).width.
    double width = context.width;
  • Height : A shortcut for calling MediaQuery.sizeOf(context).height.
    double height = context.height;
  • Is Phone : To check wether the screen width less than 400 px or not.
    bool isPhone = context.isPhone;
  • Is Desktop : To check wether the screen width more than 700 px or not.
    bool isDesktop = context.isDesktop;
  • Is Tablet : To check wether the screen width less than 400 px and more than 700 px or not.
    bool isTablet = context.isTablet;

RequestContext Extension

A set of extension collection on RequestContext.

  • Method : A shortcut to get HttpMethod out of RequestContext.
    HttpMethod method = context.method;
  • Is Get : Check whether request method is HttpMethod.get or not.
    bool isGET = context.isGET;
  • Is Post : Check whether request method is HttpMethod.post or not.
    bool isPOST = context.isPOST;
  • Is Put : Check whether request method is HttpMethod.put or not.
    bool isPUT = context.isPUT;
  • Is Delete : Check whether request method is HttpMethod.delete or not.
    bool isDELETE = context.isDELETE;
  • Is Web Socket : Check whether request method is a http request or websocket request.
    bool isWS = context.isWebSocket;
  • Parameter : A shortcut to get parameter from RequestContext.
    JSON parameter = context.parameter;
  • Header : A shortcut to get header from RequestContext.
    JSON parameter = context.parameter;
  • JWT Verify : A function to verify JWT Bearer Token.
    JWT jwt = await context.verify((key) => Env.read<String>(key));

List Extension

A set of extension collection on BuildContext.

  • To : Generate key index and value of its items.
    List<String> texts = ["one", "two", "three"];
    List<Widget> widgets = texts.to((index, item) => Text("$index: $item"));
  • Limit : Safely limitting list on certain length.
    List<int> integers = [1, 2, 3];
    List<int> sublist = integers.limit(1, 100);
    print(sublist); // [2, 3]

DModel List Extension

Extending list of DModel to get its toJSON values.

List<DModel> dmodels = [DModel(), DModel()];
List<JSON> jsons = dmodels.toJSON;

String Extension

Capitalizing the first letter of Strings.

String word = 'magnificent'.capitalize;
print(word); // Magnificent

D Image

A widget for displaying vector or bitmap images from different sources.


// Vector / Bitmap image from file
DImage(source: File('path/to/images.svg'))

// Vector / Bitmap image from asset
DImage(source: 'assets/image/image.png');

// Vector / Bitmap image from Uint8List
DImage(source: Uint8List());

// Vector / Bitmap image from network
DImage(source: 'http://image.dom/asset.svg');

D Log

A simple logging utility for printing log messages with customizable log levels.


Exception e = Exception('something');
DLog(e); // Exception: something

D Models

A collection of DModel models.

  • D Model: Base dart model which consist copyWith, toJSON, fromJSON and toString value.

    class MyModel extends DModel {
      MyModel copyWith() {
        return MyModel();
      static MyModel fromJSON(JSON value) {
        return MyModel();
      JSON get toJSON {
        return {};

  • Response Model: Basic model in root of every Response, containing success status, message and also data that extends DModel class.

      success: true,
      message: 'Successfully Fetching Data!',
      data: const ResponseDataModel());

  • Link Model: Link reference used in ResponseModel to indicate the relationship of resources.
      method: HttpMethod.get,
      description: 'Read User Detail',
      reference: '/user/123');

D Overlay

A builder widget that displays an overlay.


final overlay = DOverlay(builder: (context, progress, controller) => YourWidget());

  onTap: () {

D Parse

A utility class for parsing mostly related to http request.

  • HTTP Method Message : Parsing message of http method value like DELETE, GET, HEAD, OPTIONS, PATCH, POST or PUT.
    HttpMethod method = HttpMethod.get;
    final message = DParse.httpMethodMessage(method.name);
    print(message); // 'Data successfully loaded'
  • HTTP Status Message : Parsing message of statusCode value in [Response].
    Response response = Response(...);
    final message = DParse.httpStatusMessage(response.statusCode);
    print(message); // 'Not Found: The requested resource could not be found'
  • Exception Message : Parsing error message from [Exception].
    FormatException exception = FormatException('Unexpected end of input (at character 1)');
    final message = DParse.exceptionMessage(exception);
    print(message); // 'Data is not exist'

D Runner

Runner class for `Dart Fusion CLI'.

  • Asset Runner : Runner to scan asset and turn it into one model class.
  • Model Runner : Runner to completing DModel, like copyWith, fromJSON and toJSON.
  • Localization Runner : Runner to translate Locale and generate a model to be integrated with easy_localization.


Set this in your root main.dart

File: main.dart

void main() {
  DartFusion.runner(const [AssetRunner(), ModelRunner(), LocalizeRunner()]);

D Services

A set of service collection mosty used in dart backend.


Middleware for handling requests and responses in Dart Frog. This middleware supports both regular HTTP requests and websockets.

File: _middleware.dart

Handler middleware(Handler handler) {
  return DService.middleware(
    handler: handler,
    certificate: (key) => Env.read(key)!,
    data: ResponseDataModel.fromJSON,


Configuration class for defining Cross-Origin Resource Sharing (CORS) policies in a Dart backend application.

File: _middleware.dart

Handler middleware(Handler handler) {
  return handler.use(
      accessControlAllowOrigin: ['*'],
      accessControlAllowMethods: [HttpMethod.get, HttpMethod.post],
      accessControlAllowHeaders: [Header.contentType, Header.authorization],
      accessControlAllowCredentials: false,
      accessControlExposeHeaders: [Header.date],
      accessControlMaxAge: Duration(hours: 24)


Abstract class representing headers used in CORS policies. It has 98 child class extending this class.

Header header = ContentType();
print(header); // 'Content-Type'

Random ID

Generate simple random key identifier

String id = DService.randomID();

D Typedefs

A set of mostly used typedefs in dart.

JSONMap<String, dynamic>

D Widget Logo

D Widget

Offers a solution to simplify the boilerplate code commonly associated with using StatefulWidget. By providing a clean and efficient approach, it enhances the developer experience. Designed with convenience and simplicity in mind, AppStateWidget streamlines the development process, allowing you to focus on building intuitive user interfaces without getting bogged down by repetitive code.

Key Features

  • Reduce Boilerplate With DWidget, you can significantly reduce boilerplate code when working with StatefulWidget. Say goodbye to excessive code blocks and welcome concise, elegant declarations.
  • Improved Readability By abstracting away common patterns, the library ensures cleaner and more readable code, making it easier to comprehend and maintain your project.
  • Easy to Use Implementing DWidget is straightforward. Just extend the class, override specific methods like onStart, onPreparation, onFinish, and let the magic happen.
  • Data Passing Made Simple With a convenient data method, you can easily declare and pass data between the widget and its state, ensuring your data management is both efficient and organized.


To use it, you're going to need extending this class like this

class MyClass extends DWidget {
  const MyClass({super.key});

  Map<String, dynamic> data(DState state){
    return {'controller': TextEditingController()};

  void onPreparation(DState state){
    state.value<TextEditingController>('controller').text = 'Loading';

  Widget onStart(DState state){
    return TextField(controller: state.value<TextEditingController>('controller'));

  void onReady(DState state){
    state.value<TextEditingController>('controller').text = 'Data Loaded';

  void onFinish(DState state){

and you can also get [DState] in its child, by calling this


or get the data in [DState] with this


also to cell setState we change it to


D Change Builder

A widget that listens to changes in a ChangeNotifier and rebuilds its child widgets based on the changes.


final changeNotifier = ScrollController();

return DChangeBuilder(
  value: changeNotifier,
  builder: (context, value, child) {
    /* Your code here */
  child: AnotherWidget(),

D Provider

A generic InheritedWidget for providing an object to its descendants.


This is to set the value

  value: 'Test',
  child: MyWidget(),

and this way to get the value

var value = context.provider.value;
print(value); // 'Test'

D Tile Wrapper

A wrapper around ExpansionTile to listen changes of its state.


DTileWrapper((isExpanded) {
  return ExpansionTile(...);


For dart doc generated document, you can see it in this