Dart: a New Web Programming Experience

James Slocum — Tue, 07 May 2013 17:27:12 +0000

JavaScript has had a long-standing monopoly on client-side Web programming. It has a tremendously large user base, and countless libraries have been written in it. Surely it is the perfect language with no flaws at all! Unfortunately, that is simply not the case. JavaScript is not without its problems, and there exists a large number of libraries and "trans-pilers" that attempt to work around JavaScript's more quirky behaviors. JQuery, Coffeescript, Objective-J and RubyJS are examples of how people have been trying to make JavaScript better. However, a new contender is throwing its hat into the ring in a big way.

In comes Google Dart, a new JavaScript replacement language. Dart is a ground-up re-imagining of what JavaScript should be. It requires its own runtime environment (which Google makes available for free under the three-clause BSD license) and has its own syntax and libraries. Dart is an object-orientated language with a heavy Java-like feel, but it maintains many of the loved JavaScript paradigms like first-class functions.

So, why have I chosen to use Dart? Good question! I have chosen Dart because it is a clean break from JavaScript, and it has the object-orientated programming style I have come to know and love. Because I have a Java background, the learning curve didn't seem as steep with Dart as it does with JavaScript. Also, because Dart is so new, it gives me a chance to become an early adopter of the language and watch its evolution.

Installing Dart

Before you can program with Dart, you need to grab a copy from https://dartlang.org. I chose to install only the SDK; however, there is an option to grab the full Dart integrated development environment with the SDK included. Eclipse users will feel right at home with the IDE, because it is based on Eclipse components.

To install the SDK, I just unzipped the files and copied the whole directory to $HOME/bin. Then I modified my path variable to look in the folder I created:


PATH=$PATH:$HOME/bin/dart-sdk/bin

Now I can run dart, dart2js and dartdoc from anywhere.

Language Features

The core Dart language is pretty straightforward. The basic data types available are var (stores any object), num (stores any number type), int, double, String, bool, List (arrays) and Map (associative array). All of these data types are declared in the dart:core library. dart:core is always available and does not need to be imported. Functions also can be considered a data type, because Dart treats them as first-class objects. You can assign functions to variables and pass them as parameters to other functions or write anonymous functions in-line.

For flow control, you have the "usual" if, else if, else, for, while and do-while loops, break, continue, switch and assert. Exceptions are handled through try-catch blocks.

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