const navLeft = [
    <NavBtn key="back" icon={faLeftLong} onClick={() => history.back()} />,
];
const navRight = [
    <NavBtn key="delete" icon={faTrash} to={`/bookmarks/${id}/delete`} />,
    <NavBtn key="edit" icon={faEdit} to={`/bookmarks/${id}/update`} />,
];

// ...

<Nav left={navLeft} right={navRight} />