Getting started with dart

Remarks#

Dart is an open-source, class-based, optionally-typed programming language for building web applications—on both the client and server—created by Google. Dart’s design goals are:

• Create a structured yet flexible language for web programming.
• Make Dart feel familiar and natural to programmers and thus easy to learn.
• Ensure that Dart delivers high performance on all modern web browsers and environments ranging from small handheld devices to server-side execution.

Dart targets a wide range of development scenarios, from a one-person project without much structure to a large-scale project needing formal types in the code to state programmer intent.

To support this wide range of projects, Dart provides the following features and tools:

• Optional types: this means you can start coding without types and add them later as needed.
• Isolates: concurrent programming on server and client
• Easy DOM access: using CSS selectors (the same way that jQuery does it)
• Dart IDE Tools: Dart plugins exist for many commonly used IDEs, Ex: WebStorm.
• Dartium: a build of the Chromium Web Browser with a built-in Dart Virtual Machine

Links

• The Dart Homepage
• Official Dart News & Updates
• The Dartosphere - A collection of recent Dart blog posts
• Dartisans Dartisans community on Google+
• Dart Web Development - Google Groups Page
• Dart Language Misc - Google Groups Page
• DartLang sub-Reddit

Documentation

• Tour of the Dart Language
• Tour of the Dart Libraries
• Dart Code samples
• Dart API Reference

FAQ

• Frequently Asked Questions

Versions#

Installation or Setup

The Dart SDK includes everything you need to write and run Dart code: VM, libraries, analyzer, package manager, doc generator, formatter, debugger, and more. If you are doing web development, you will also need Dartium.

Automated installation and updates

• Installing Dart on Windows
• Installing Dart on Mac
• Installing Dart on Linux

Manual install

You can also manually install any version of the SDK.

Hello, World!

Create a new file named hello_world.dart with the following content:

void main() {
  print('Hello, World!');
}

In the terminal, navigate to the directory containing the file hello_world.dart and type the following:

dart hello_world.dart

Hit enter to display Hello, World! in the terminal window.

Http Request

Html

<img id="cats"></img>

Dart

import 'dart:html';

/// Stores the image in [blob] in the [ImageElement] of the given [selector].
void setImage(selector, blob) {
  FileReader reader = new FileReader();
  reader.onLoad.listen((fe) { 
    ImageElement image = document.querySelector(selector);
    image.src = reader.result;
  });
  reader.readAsDataUrl(blob);  
}

main() async {
  var url = "https://upload.wikimedia.org/wikipedia/commons/2/28/Tortoiseshell_she-cat.JPG";

  // Initiates a request and asynchronously waits for the result.
  var request = await HttpRequest.request(url, responseType: 'blob');
  var blob = request.response;
  setImage("#cats", blob);
}

Example

see Example on https://dartpad.dartlang.org/a0e092983f63a40b0b716989cac6969a

Getters and Setters

void main() {
  var cat = new Cat();
  
  print("Is cat hungry? ${cat.isHungry}");  // Is cat hungry? true
  print("Is cat cuddly? ${cat.isCuddly}");  // Is cat cuddly? false
  print("Feed cat.");
  cat.isHungry = false;                     
  print("Is cat hungry? ${cat.isHungry}");  // Is cat hungry? false
  print("Is cat cuddly? ${cat.isCuddly}");  // Is cat cuddly? true
}

class Cat {
  bool _isHungry = true;
  
  bool get isCuddly => !_isHungry;
  
  bool get isHungry => _isHungry;
  bool set isHungry(bool hungry) => this._isHungry = hungry;
}

Dart class getters and setters allow APIs to encapsulate object state changes.

See dartpad example here: https://dartpad.dartlang.org/c25af60ca18a192b84af6990f3313233