The supported functions are:
add, andSelf, attr, each, end, eq, extend, filter,
get, implement, include, index, init, is, map, not,
pushStack, setArray, size and slice.
$.collection is a collection class by itself. So other collections will inherit from it, or its subclasses. The filter() function accepts:
* A function that returns true/false.
* Anything else will be taken literally and compared. Only those items included pass the filter. The filter can be an array of items.
The function .not() works the same way, but matches the opposite.
u can Downloads collection from here: