It's not about the language, it's about the tools
That should come as no surprise, given that Microsoft is arguably the leading commercial developer tools vendor. Even some Redmond haters grudgingly admit that Visual Studio is one of the best IDEs in the business.
This static typing in TypeScript is completely optional. Developers can add type annotation to all of their objects and variables or just a few. In fact, Hejlsberg said, specifying types for just a few identifiers in a program is often enough to allow the TypeScript parser to infer the rest automatically.
"Before we declare [TypeScript] 'done,' if ECMAScript 6 moves to a different model, then we will likely follow, because we're still just a preview of what the final product will be," Hejlsberg said.
What's next for TypeScript?
But similarities between TypeScript and ECMAScript 6 don't mean they are the same language, nor will they ever be. Specifically, Hejlsberg said, there are no plans to include static typing in ECMAScript, which is the feature that really sets TypeScript apart and that enables the kind of sophisticated tooling that Microsoft envisions.
And while some of that tooling is already available in the TypeScript plugin for Visual Studio 2012, he said, Microsoft has still more planned. In particular, limited support for debugging TypeScript code is available now, but "thorough" support will come with future releases.
The TypeScript language will undergo further changes, too. One feature Hejlsberg said he would like to add to the language was generics, which he said would be inspired by C# generics but would work differently.
The mention of C# spurred another question that had been much on the minds of this year's Build conference attendees, however: If Hejlsberg, the father of C#, is spending all of his time on TypeScript these days, what does it mean for the leading language of .Net? Does C# have a future?
Judging by the large and animated crowd at Hejlsberg's Build session – who had to be ushered out of the room to make way for a new session before all of their questions could be answered – a great many developers agree. ®