[spankalee]

I'm on the Dart team and I can honestly say that we're working very hard on this.

We simply have a harder problem to solve than TypeScript (different features and semantics, working with the VM as well as compiling to JavaScript), so it's taking longer, but we're aiming for nothing short of awesome and seamless interop.

We already have dart:js, a low-level JS-interop library that works in dart2js and with the Dart VM. Admittedly it's a bit cumbersome for developers to use, but it provides the building blocks that we can use to make TypeScript-like Dart interfaces for JavaScript libraries, and to export Dart libraries to JavaScript.

It's great to hear about a project like DefinitelyTyped, because once we have the support in place, we're going to need something very much like it in Dart.