why is js's implementation of reverse() so awful

reverse.js

> var a = [1,2,3]
undefined
> a.reverse()
[ 3, 2, 1 ]
> a
[ 3, 2, 1 ]

// [insert price is right losing horn here]

reverse.py

>>> arr = [1, 2, 3]
>>> ret = arr.reverse()  # mutates arr
>>> print ret
None
>>> arr
[3, 2, 1]

>>> arr = [1, 2, 3]
>>> reversed(arr)  # does not mutate arr
<listreverseiterator object at 0x101763610>
>>> [x for x in reversed(arr)]
[3, 2, 1]
>>> arr
[1, 2, 3]

reverse.rb

irb(main):001:0> a = [1,2,3]
=> [1, 2, 3]
irb(main):002:0> a.reverse
=> [3, 2, 1]
irb(main):003:0> a
=> [1, 2, 3]
irb(main):004:0> a.reverse!
=> [3, 2, 1]
irb(main):005:0> a
=> [3, 2, 1]