Pretty weird this verson of Babel doesn't support str.endsWith(searchString[, position]) method.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith

This should be at the top. Insanely elegant solution. Thank you!

Marked as resolved.

Thank you, now I got it :)

I think description should be a tiny bit tweaked though.
Should I resolve the issue?

Not correct Python tests.

As per description "If array contains not numbers it returns string 'array should contain only numbers'. So make sure all elements of the array are numbers" => thus only numbers are allowed in a list/array.

But the first test case is:

Test.assert_equals(map([1,2,3,'8'],func),[ False, True, False, True])

Since '8' is not a number we should get a 'array should contain only numbers' string.

That's a sweet solution, so elegant.

It's broken, even past solutions won't work here.
Just wasted an hour.

Very elegant solution (y).