So good to see String.prototype.startsWith and String.prototype.endsWith in ES6. I've ended up implementing these in too many projects. I look forward to using these in 2020 or 5 years after that, when IE 8 finally sunsets. (I joke of course, since you can use ES6 to 5 with IE 8 caveats with the modern taskrunners).

EDIT: Blockscope... what? More than a few of these changes point to JS being a functional version of PHP, but doesn't blockscope just fundamentally change the language?