
{{alias}}( x, filter )
    Splits array element indices into two groups.

    If an element in `filter` is truthy, then the corresponding element in the
    input array belongs to the first group; otherwise, the array element belongs
    to the second group.

    If provided an empty array, the function returns an empty array.

    Parameters
    ----------
    x: ArrayLike
        Input array.

    filter: ArrayLike
        An array indicating which group an element in the input array
        belongs to. If an element in `filter` is truthy, the corresponding
        element in the input array belongs to the first group; otherwise, the
        array element belongs to the second group.

    Returns
    -------
    out: Array<Array>
        Group results.

    Examples
    --------
    > var x = [ 'beep', 'boop', 'foo', 'bar' ];
    > var f = [ true, true, false, true ];
    > var out = {{alias}}( x, f )
    [ [ 0, 1, 3 ], [ 2 ] ]
    > f = [ 1, 1, 0, 1 ];
    > out = {{alias}}( x, f )
    [ [ 0, 1, 3 ], [ 2 ] ]

    See Also
    --------

