{{alias}}( iterator, fcn[, thisArg] )
    Returns an iterator which both filters and maps a provided iterator's
    values.

    When invoked, the callback function is provided two arguments:

    - value: iterated value.
    - index: iteration index (zero-based).

    If the callback returns `undefined`, the iterator invokes the function for
    the next value of the provided iterator; otherwise, the iterator returns
    the callback's return value.

    If an environment supports Symbol.iterator and a provided iterator is
    iterable, the returned iterator is iterable.

    Parameters
    ----------
    iterator: Object
        Input iterator.

    fcn: Function
        Callback function which both filters and maps.

    thisArg: any (optional)
        Execution context.

    Returns
    -------
    iterator: Object
        Iterator.

    iterator.next(): Function
        Returns an iterator protocol-compliant object containing the next
        iterated value (if one exists) and a boolean flag indicating whether the
        iterator is finished.

    iterator.return( [value] ): Function
        Finishes an iterator and returns a provided value.

    Examples
    --------
    > function f( v ) { if ( v > 2 ) { return v * 10 }; };
    > var it1 = {{alias:@stdlib/array/to-iterator}}( [ 1, 3, 2, 4 ] );
    > var it2 = {{alias}}( it1, f );
    > var v = it2.next().value
    30
    > v = it2.next().value
    40

    See Also
    --------