A different way to put it is: "the best way to iterate over collections is still being discussed, because we want to get it right".

Also, for `Map`, how do you think `foreach` should work? Should the function be called with (a) the key, (b) the value, (c) an array with both the key and the value, (d) the key and the value as separate arguments?

Similarly, in the statement:

    for(let x of some_map) { ... }

should `x` range over the keys, values, or key-value pairs of the map?