Преобразовать дерево в меню (Яндекс)

/*
    Преобразование дерева в пункты меню по уровням вложенности
    пример дерева:
    [
        {
            name: '1',
            items: [
                {name: '1-1'},
                {
                    name: '1-2',
                    items: [
                        {name: '1-2-1'}
                    ]
                }
            ]
        },
        {
            name: '2'
        },
        {
            name: '3',
            items: [
                {name: '3-1'},
                {
                    name: '3-2',
                    items: [
                        {name: '3-2-1'},
                        {name: '3-2-2'}
                    ]
                },
                {name: '3-3'}
            ]
        }
    ]
*/

function menu(tree) {
    let count = tree.length;
    let result = {};
    let level = 0;

    while ( tree.length > 0 ) {
       let cur = tree.shift();
       if (cur.items && cur.items.length > 0) {
            cur.items.forEach(el => {
                tree.push(el);
            })
       }

       if (level in result) {
            result[level].push(cur.name)
       } else {
            result[level] = [cur.name]
       }

       if (--count === 0) {
            count = tree.length;
            level++;
       }
    }

    return Object.values(result);
}


console.log(menu(menuTree))