Rubyisms are ES5 prototype extensions.
They're pretty neat. Here's a few examples.
var s = 'Hello world!;
alert(s.reverse);
(2).times(function (n) {
alert('Yo x ' + n);
});
(7).upto(10, function (n) {
alert(n + ' is odd? ' + n.odd);
});
var a = ['1', 1, 1, '1', 1],
nums = a.count(function (e) {
return e.numeric;
});
alert(nums);
var a = ['one', 'two', 'three'];
alert(a.sample.chop)