Inconsistent output compared with other JS engines when using sort()

Hello,
The following code behaves strangely (inconsistent with other engines).

a=[3.3,2.2,1];
a.sort(function () { return -1;});

In Safari, output is
[1, 2.2, 3.3]
However, output should be:
[3.3, 2.2, 1]

BT group
2018.6.28

[Yusuke Suzuki]

I think this is OK. This relies on how comparator is called (since it does not produce consistent results, comp(a, b) => -1 comp(b, a) => -1), and it is implementation dependent according to the spec.