push-undefined-wtf.js

> (function (arg) { return arg === undefined; }()) // Missing arguments are undefined
true
> var items = []
undefined
> items.push() // Pushing implicitly undefined item doesn't work
0
> items
[]
> items.push(undefined) // What about explicitly pushing undefined?
1
> items // wtf
[undefined]
> (function (arg) { return arguments.length; }()) // Ahh, but now it makes sense, still WTF
0
> (function (arg) { return arguments.length; }(undefined))
1