I agree with Dhugal. We are(were?) evaluating Sencha for a big project and that a seemingly official representative of Sencha was making those dismissive comments is disturbing and bad for Sencha's business.
If Sencha embraces these other languages, then they're more likely to not lose business when other toolkits come out for Typescript.
This is my first result, don't know if it really works runtime, but at least I get no compiler errors anymore .
Maybe the documentation can be added to. (so you can get JS documentation text in Visual Studio).