def get_descendant_ids(node):
    """
    This filter returns the ids of all the node's descendants.

    :param node: The requested node
    :type node: ~integreat_cms.cms.models.abstract_tree_node.AbstractTreeNode

    :return: The list of all the node's descendants' ids
    :rtype: list [ int ]
    """
    return [
        descendant.id for descendant in node.get_cached_descendants(include_self=True)
    ]