[pvg]

Flow and TypeScript are used a fair bit and both have adoption in big organizations that make big, commonly used tools. I don't think any of the compile-to-JS languages have ever really got quite that far and I'm somewhat skeptical they will.

[fulafel]

Ah. I guess due to the superset-of-JS property you might kinda sorta see it as annotated JS, though it has its own syntax and has to go through a compiler to produce runnable JS.

edit: Seems the TS tools also have JS linting functionality, where you put JSDoc annotations in comments and use the new --checkJs options, I guess you may have meant this too.