Determines whether any element of an observable sequence satisfies a condition if present, else if any items are in the sequence. There is an alias to this method called
Function): A function to test each source element for a condition. The callback is called with the following information:
- the value of the element
- the index of the element
- the Observable object being subscribed
Any): Object to use as this when executing callback.
Observable): An observable sequence containing a single element determining whether all elements in the source sequence pass the test in the specified predicate.