(Wikipedia)
“Some examples, like Dart, portend that JavaScript has fundamental flaws and to support these scenarios requires a ‘clean break’ from JavaScript in both syntax and runtime. We disagree with this point of view.” - Microsoft’s JavaScript team
If Google comes out with Dart, well, then there's no need for that. But it's ok for Microsoft to be secretly working on their own Javascript 2.0. Just sayin' - Why criticize Dart when you've just come with almost the same thing? :)
Also, no "JS will be replaced" threat, no proprietary native VM in IE-prototype to advantage it over other browsers running TypeScript compiled to JS.
But I agree it is another case of two-faced behavior, not in the way you suggest. The IE blog post against Dart rejects a "clean break" and TypeScript builds on ES6. That's consistent.
What is not consistent is how similar parts (but not all) of TypeScript are to ES4, which MS opposed vigorously. Time has passed and ES4 had its own problems, so bygones.
Treating Microsoft as a single, whole, coherent, consistent, and logical entity is the first mistake you make when trying to understand their actions and motivations.
If Google comes out with Dart, well, then there's no need for that. But it's ok for Microsoft to be secretly working on their own Javascript 2.0. Just sayin' - Why criticize Dart when you've just come with almost the same thing? :)
But snark aside, good job Microsoft. Well done.