// The arrays:

const data = [{
        id: 1,
        name: 'package1',
        rows: [{
            id: 2,
            name: 'item2',
            rows: [{
                    id: 3,
                    name: 'item 3',
                    rows: [{
                            id: 4,
                            name: 'item 4',
                        },
                        {
                            id: 5,
                            name: 'item 5',
                        }
                    ]
                },
                {
                    id: 6,
                    name: 'item 6',
                }
            ]
        }]
    },
    {
        id: 7,
        name: 'item 7',
    },
];


const data_with_groups = [{
        id: 'g1',
        name: 'group1',
        rows: [{
                id: 1,
                name: 'package1',
                rows: [{
                    id: 2,
                    name: 'slot 99',
                    rows: [{
                            id: 3,
                            name: 'item 2',
                            rows: [{
                                    id: 4,
                                    name: 'item 7',
                                },
                                {
                                    id: 5,
                                    name: 'item 9',
                                }
                            ]
                        },
                        {
                            id: 6,
                            name: 'item 3',
                        }
                    ]
                }]
            },
            {
                id: 7,
                name: 'item 0',
            },
        ]
    },
    {
        id: 'g2',
        name: 'group2',
        rows: []
    }
];

function find( id, rows, parent_item ) {
    for ( let [index, item] of rows.entries() ) {
        if ( id === item.id )
            return parent_item;

        if ( 'rows' in item )
            return find( id, item.rows, item );
    };
}

console.log( find(3, data).id );             // 2
console.log( find(5, data_with_groups).id ); // 3
console.log( find(7, data_with_groups) );    // undefined, because there is no parent object