As of today, we now know more about the formerly secret Microsoft JavaScript effort upon which Technical Fellow and father of C# Anders Hejlsberg has been working.

On October 1, Microsoft took the wraps off TypeScript, a new programming language that is aimed at making JavaScript development scale beyond the client.

Microsoft has made available to those interested via its CodePlex site a preview of the TypeScript bits; the TypeScript language specification; and the source code for the TypeScript compiler. TypeScript is available under an Apache 2.0 open-source license. In addition to the new TypeScript language and compiler, Microsoft also plans to make available a TypeScript for Visual Studio 2012 plug-in, providing JavaScript developers with Visual Studio features like code navigation, refactoring, static error messages and IntelliSense.

A Microsoft Channel 9 video of Hejlsberg discussing TypeScript is available on Microsoft's Web site:

Soma Somasegar, Corporate Vice President of Microsoft' Developer Division, outlined the problem space that Microsoft believes it can solve with TypeScript in an October 1 blog post:

"With HTML5, the standards web platform has become significantly more compelling for delivering rich user experiences. At the same time, the reach of JavaScript has continued to expand, going beyond the browser to include native device apps (e.g. Windows Store apps for Windows 8), applications in the cloud (e.g., node.js running on Windows Azure), and more. With these developments, we’re starting to see applications of unprecedented size written with JavaScript, despite the fact that creating large-scale JavaScript applications is hard. TypeScript makes it easier."

Microsoft is building the TypeScript "superset" of JavaScript to provide the "syntactic sugar" needed to build large applications and support large teams, Somasegar blogged. TypeScript will provide better JavaScript tooling to users writing client-side apps or server/cloud-side ones, Somasegar said. The kinds of tools that typically have been available only for statically-typed languages will be available for JavaScript via TypeScript, he said.

I got a couple of tips about Hejlsberg & Co.'s JavaScript effort leading up to today's announcement. One of them posited that that Microsoft's new JavaScript project (which this person said was codenamed "Strada" internally -- a name upon which Microsoft officials wouldn't comment) -- was yet another example of Microsoft's good old "embrace and extend" philosophy. (Update: Looks like the codename for TypeScript was, indeed, Strada. Thanks, Felix9!)

Hejlsberg and the others working on TypeScript disagreed with that characterization. Microsoft is building TypeScript so that JavaScript code already developed can easily be brought into the TypeScript world because, as Somasegar claimed on his blog, "all JavaScript code is already TypeScript code."

Microsoft's official site for TypeScript is http://www.typescriptlang.org/.

What are your initial thoughts on what the Softies are doing, any of you developer-readers out there?

Update: In spite of the Somasegar quote above regarding the Windows Store -- if you still were unsure whether you can build Windows Store apps for Windows 8 and Windows RT using TypeScript, the answer is yes.