The issue with coffeescript is that it uses the opposite syntax to JS - `in` for arrays instead of objects. ES6 introduces the `of` keyword for real iterators so i don't really want to use that for either of them. It's tricky.
There are other options but they're verbose
every element as key, value from arr {
console.log(key, value);
}
every property as key, value from obj {
console.log(key, value);
}