The Google Dart team has announced Dart SDK 1.3 which improves the performance of asynchronous server-side code to the point that Dart VM is on par with Node.js, the later using another Google technology, the V8 engine.
JetBrains has just released WebStorm 7.0 GA with support for EJS, Mustache, Handlebars, Web Components, Stylus, Karma, Istanbul, Compass, and comes with various enhancements.
Google Dart is going to dump Web UI, replacing it with Polymer. From the outside, the main differences are in data binding and handling events.
20 months after the initial announcement of Dart, the language and its associated VM have entered beta with milestone M5. There are many small improvements in the current release, the most important ones being related to the Editor, VM, and dart2js.
The Google Dart team has released milestone 4 of its SDK. While the language had already stabilized in previous milestones, this M4 release stabilizes some core libraries. Performance has also improved. The DartVM, which runs Dart natively, is now between 160% (for the DeltaBlue benchmark) and 200% (for the Richards benchmark) faster than v8. The release also includes the faster dart2js compiler.
The first binaries of Dartium, Chrome with a built-in Dart VM, are now available for download. Dartium has the beginnings of debugging support in Dev Tools. Meanwhile, a lot of documentation resources have become available both from Google and outside.