This book will help you learn the Dart language, understand the Dart ecosystem, and write Dart code targeted to run in modern web browsers and on the server. You’ll use the latest HTML5 technologies to build apps capable of running disconnected in the browser and create Dart servers capable of two-way communication with browsers.

As a structured language, Dart is ideal for building large-scale apps in distributed teams. And with tools to enable automatic checking and validation of your and your fellow developers’ code, Dart helps make your life as a developer easier.

Audience

This book is aimed at developers who have been frustrated by the lack of structure and tooling available to them when building browser-based apps. If you have a working knowledge of Java, C#, or JavaScript, then you’ll be able to dive right in and get working with Dart.

Whether you prefer to build interactive user interfaces or are happier creating efficient back-end code, you’ll find that Dart, combined with modern browser technology, brings the structure of the server to the front end, and the flexibility, dynamism, and speed of browser development to the back end.

Whether you’re a novice web developer or are experienced with writing structured code, this book will help you get up to speed with Dart language concepts. The book uses an example-based format, with examples throughout each chapter to introduce new concepts. The text indicates Dart’s similarities to other languages such as Java and JavaScript, as well as shows its differences.

Like Java, Dart has great tools; and like JavaScript, Dart doesn’t require a compile step, which means that with this book you can quickly get ready to start building client and server Dart applications.

Roadmap

This book is structured to get you working with Dart as quickly as possible. It’s split into four parts. Part 1 includes overview chapters designed to get you up and running with Dart:

• Chapter 1 provides an overview of the language features and concepts and why Dart exists. If you’ve ever been exasperated by the lack of typing and documentation that could be encoded in a browser-based language, this chapter will help you to understand the philosophy behind Dart. This base will give you an idea of the types of large-scale web apps you can build with Dart.
• Chapter 2 discusses the wider Dart ecosystem, including the rich tooling you get by choosing a structured web-development language created by a market-leading web company. With the technical resources to concentrate on a whole-developer experience, rather than just the language, Google has created an IDE, a custom Dart browser for rapid development, a server-side virtual machine, and other tools to help you build quality code.
• In chapter 3, you’ll build an example web app, getting a taste of how Dart interacts with the browser. You’ll build a user interface, listen for browser events, and create unit tests to confirm the validity of your code.

Part 2 covers the core language features:

• Chapter 4 examines functions, which are first-class objects in Dart. JavaScript developers will be familiar with some of the techniques of functional programming, but Java and C# developers will find many new ideas that are common practice in browser-based web development.
• Chapter 5 moves on to building the structure of your app by using Dart’s library system, and shows how that relates to privacy. Dart’s privacy mechanism might surprise Java and C# developers and will be a welcome treat to those experienced with JavaScript.
• Chapters 6, 7, and 8 explore Dart’s class and interface structure. Classes form the backbone of any reasonable-size app, and knowing how to effectively build class hierarchies and use library classes provided by other developers is an essential skill.
• Chapter 9 returns to functional programming to explore the asynchronous nature of web APIs. You’ll learn how to work with future values, that is, variables that will have a value at some point in the future. This will leave you ready to start working with the APIs provided by Dart’s client and server libraries.

Part 3 discusses building client-side browser apps:

• In chapter 10, you’ll learn about Dart’s event loop and create a user-interface in Dart.
• Chapter 11 builds on the structure of your app to add browser-based navigation, persistent client-side storage, and interaction with the JSON data format.
• By chapter 12, you’ll be ready to start connecting your app to external systems, such as external JavaScript and third-party server APIs. Although Dart is targeted at all modern web browsers, in this chapter you’ll also learn how to package your app for deployment as a Chrome app in Google’s Web Store.

When you reach part 4, you’ll be ready to hook up your app with the server side:

• Chapter 13 introduces building a command-line Dart application, accessing the filesystem, and serving HTTP data to build a simple file server.
• Chapter 14 builds on client-side communication by connecting the client side to a server-side database and performing two-way communication with WebSockets technology to push data to the client.
• In chapter 15, knowing how to interact with the server, you’ll be ready to learn how Dart achieves concurrency through its system of isolates, a message-passing threading model that provides a safer means of concurrency than the equivalent in Java or C#. You’ll also use the isolate system to load Dart code dynamically into your running application. This gives you a great basis for building plug-ins and extensions into your app.

The appendixes provide a concise reference to and examples of the core Dart language, giving you a quick guide to Dart’s specific syntax idiosyncrasies and quirks.

Code conventions and downloads

All the source code in the text uses a fixed width font like this. The text contains many code snippets and diagrams, and there are complete, annotated code listings to show key concepts. These code listings, snippets, and diagrams usually relate to the surrounding body text and are a key part of learning Dart.

In some cases, code has been reformatted to fit the page, but in general, the code has been written to take page width into account. Although the examples are often simple in order to to show a key concept or example, the body text and code annotations provide additional depth.

Source code for the examples in this book is avaiable for download from the publisher’s website at www.manning.com/DartinAction.

Software requirements

Working with Dart requires at the very least the Dart SDK, which is available from www.dartlang.org. The Dart SDK is included in the Dart Editor download, which also includes the custom Dart browser, Dartium (essential for rapid Dart development), and the Dart to JavaScript converter. This download is available for Windows, Mac, and Linux.

Author Online

Your purchase of Dart in Action includes free access to a private web forum run by Manning Publications, where you can make comments about the book, ask technical questions, and receive help from the author and from other users. To access the forum and subscribe to it, point your web browser at www.manning.com/DartinAction. This page explains how to get on the forum once you are registered, what kind of help is available, and the rules of conduct on the forum.

Manning’s commitment to its readers is to provide a venue where a meaningful dialogue among individual readers, and between readers and the author, can take place. It’s not a commitment to any specific amount of participation on the part of the author, whose contribution to the forum remains voluntary (and unpaid). We suggest you try asking the author some challenging questions, lest his interest stray!

The Author Online forum and archives of previous discussions will be accessible from the publisher’s website as long as the book is in print.

About the author

Chris Buckett is a technical consultant responsible for delivering enterprise-scale, web-based business applications. Chris runs the popular Dartwatch.com blog and is an active contributor to the dartlang mailing list.

At a time when it is hard to tell one computer book from another, Manning celebrates the inventiveness and initiative of the computer business with book covers based on the rich diversity of regional life of two centuries ago, brought back to life by Carrara’s pictures.