Skip to main content

AngularDart -A Comprehensive Guide

AngularDart is a powerful framework for building complex web applications using the Dart programming language. It is based on the popular Angular framework developed by Google. In this tutorial, we will explore the introduction, history, features, and provide several examples of AngularDart.

Introduction​

AngularDart is a client-side web application framework that allows developers to build dynamic and responsive web applications. It is built using the Dart programming language, which is developed by Google and provides a productive and efficient way to build web applications.

One of the key advantages of AngularDart is its use of declarative templates, which allow developers to define the structure and behavior of the application's UI using HTML-like syntax. These templates are then compiled into efficient and optimized JavaScript code, which is executed in the browser.

History​

AngularDart was initially released in 2013 as an alternative to AngularJS, which was written in JavaScript. The goal was to provide a more efficient and productive way to build web applications using the Dart programming language.

Over the years, AngularDart has evolved and gained popularity among web developers. It has a strong community support and is actively maintained by Google. The latest version of AngularDart is AngularDart 6, which was released in May 2021.

Features​

AngularDart offers a wide range of features that make it a powerful framework for building web applications. Let's explore some of its key features:

1. Component-based Architecture​

AngularDart follows a component-based architecture, where the UI is divided into reusable and independent components. Each component encapsulates its own logic, HTML template, and styling. This modular approach makes the code more maintainable, testable, and reusable.

Here's an example of a simple AngularDart component:

import 'package:angular/angular.dart';

@Component(
  selector: 'hello-world',
  template: '<h1>Hello, World!</h1>',
)
class HelloWorldComponent {}

In the above code snippet, we define a component called HelloWorldComponent with a selector hello-world and a template that displays a simple "Hello, World!" message.

2. Dependency Injection​

AngularDart provides a built-in dependency injection system that allows developers to easily manage the dependencies between different components and services. This helps in creating loosely coupled and reusable code.

Here's an example of using dependency injection in AngularDart:

import 'package:angular/angular.dart';

@Injectable()
class Logger {
  void log(String message) {
    print(message);
  }
}

@Component(
  selector: 'hello-world',
  template: '<button (click)="logMessage()">Log Message</button>',
)
class HelloWorldComponent {
  final Logger _logger;

  HelloWorldComponent(this._logger);

  void logMessage() {
    _logger.log('Hello, World!');
  }
}

In the above code snippet, we define a Logger service with a log method. The HelloWorldComponent component has a dependency on the Logger service, which is injected into its constructor. When the "Log Message" button is clicked, the logMessage method is called, which in turn calls the log method of the Logger service.

3. Two-way Data Binding​

AngularDart provides two-way data binding, which allows developers to easily synchronize data between the UI and the underlying component. When the data in the component changes, the UI is automatically updated, and vice versa.

Here's an example of two-way data binding in AngularDart:

import 'package:angular/angular.dart';

@Component(
  selector: 'hello-world',
  template: '<input [(ngModel)]="message"><p>{{ message }}</p>',
)
class HelloWorldComponent {
  String message = 'Hello, World!';
}

In the above code snippet, we bind the message property of the component to an input field using the ngModel directive. Any changes made to the input field will automatically update the message property, and the updated value will be displayed in the paragraph element below.

4. Routing​

AngularDart provides a powerful routing system that allows developers to create navigation within their applications. It supports both static and dynamic routing, and allows for lazy loading of modules.

Here's an example of routing in AngularDart:

import 'package:angular/angular.dart';

@Component(
  selector: 'app',
  template: '''
    <h1>AngularDart Routing Example</h1>
    <nav>
      <a routerLink="/home">Home</a>
      <a routerLink="/about">About</a>
    </nav>
    <router-outlet></router-outlet>
  ''',
)
class AppComponent {}

@Component(
  selector: 'home',
  template: '<h2>Home Page</h2>',
)
class HomeComponent {}

@Component(
  selector: 'about',
  template: '<h2>About Page</h2>',
)
class AboutComponent {}

void main() {
  runApp(ng.AppComponentNgFactory);
}

In the above code snippet, we define an AppComponent component that serves as the root component of the application. It contains a navigation bar with links to the "Home" and "About" pages. The router-outlet directive is used to render the appropriate component based on the current route.

Examples​

Now let's explore a few more examples to showcase the power and flexibility of AngularDart.

Example 1: Todo List App​

Here's a simple example of a todo list app built with AngularDart:

import 'package:angular/angular.dart';

class Todo {
  String text;
  bool completed;

  Todo(this.text, {this.completed = false});
}

@Component(
  selector: 'todo-list',
  template: '''
    <ul>
      <li *ngFor="let todo of todos">
        <input type="checkbox" [(ngModel)]="todo.completed">
        {{ todo.text }}
      </li>
    </ul>
  ''',
)
class TodoListComponent {
  List<Todo> todos = [
    Todo('Task 1'),
    Todo('Task 2'),
    Todo('Task 3'),
  ];
}

void main() {
  runApp(ng.TodoListComponentNgFactory);
}

In this example, we define a Todo class to represent a single todo item. The TodoListComponent component then uses the *ngFor directive to iterate over an array of Todo objects and display them as a list. The [(ngModel)] directive is used to bind the completed property of each todo item to a checkbox.

Example 2: Form Validation​

AngularDart provides built-in form validation features that make it easy to validate user input. Here's an example of a simple form with validation:

import 'package:angular/angular.dart';

@Component(
  selector: 'login-form',
  template: '''
    <form (ngSubmit)="login()">
      <input type="text" name="email" [(ngModel)]="email" required>
      <input type="password" name="password" [(ngModel)]="password" required>
      <button type="submit" [disabled]="!loginForm.valid">Login</button>
    </form>
  ''',
)
class LoginFormComponent {
  String email;
  String password;

  bool get loginFormValid => email.isNotEmpty && password.isNotEmpty;

  void login() {
    // Perform login action
  }
}

void main() {
  runApp(ng.LoginFormComponentNgFactory);
}

In this example, we define a LoginFormComponent component that represents a login form. The input fields are bound to the email and password properties using the [(ngModel)] directive. The required attribute is used to mark the fields as required. The loginFormValid computed property is used to enable/disable the login button based on the form's validity.

Conclusion​

AngularDart is a powerful framework for building complex web applications using the Dart programming language. It provides a wide range of features, including a component-based architecture, dependency injection, two-way data binding, and routing. The examples provided in this tutorial demonstrate some of the capabilities of AngularDart. To learn more about AngularDart, refer to the official documentation.