Fair enough. I just haven't heard of the ECMAScript standards committee seriously considering adding static type checking to the language. The closest things I've seen are the proposed guards [1] and trademarks [2] features for ES7.

[1]: http://wiki.ecmascript.org/doku.php?id=strawman:guards [2]: http://wiki.ecmascript.org/doku.php?id=strawman:trademarks