Not possible to set numeric keys, even with multiple numbers like "5.1.1", on an object

[BennyAlex]

My keys have multiple numbers seperated by dot.

In this check:

the isNaN return false. We should only check for positive whole numbers here, all other numbers are not valid array indexes.

But I also wonder why its not allowed to set a numeric key in an object at all. Its not going against any JS rules. It should be possible.