jQuery.map( jQuery() ) does not enumerates all method names.
|Reported by:||rkatic||Owned by:|
Documentation: "Array-like objects, such as jQuery collections, are treated as arrays. In other words, if an object has a .length property and a value on the .length - 1 index, it is traversed as an array."
jQuery() has length == 0, and no value at index -1, so by definition it will not be considered array-like!
But strangely if the empty jquery is from an iframe, $.map correctly enumerates all properties: #8995.
Related tickets: #9023