Здравствуйте, не могу разобраться с ошибкой в js коде связана с датой

let students = [

        {
            Name: 'Иванова',
            LastName: 'Елена',
            Surname: 'Григорьевна',
            Birthday: new Date(1999, 2, 5), 
            StartYear: 2018,
            Faculty: 'Физика'
        },
    
        {
            Name:'Наталья',
            LastName:'Ивановна',
            Surname:'Лысенко',
            Birthday: new Date(2004, 3, 1),
            StartYear: 2022,
            Faculty:'Биология',
        },
    
        {
            Name:'Артем',
            LastName:'Андреевич',
            Surname:'Мурзин',
            Birthday: new Date(2005, 9, 22),
            StartYear:2019,
            Faculty:'История',
        },
    
        {
            Name:'Николай',
            LastName:'Николаевич',
            Surname:'Наумов',
            Birthday:new Date(2003, 6,22),
            StartYear: 2023,
            Faculty:'Физика',
        },
    
        {
            Name:'Виктория',
            LastName:'Олеговна',
            Surname:'Максимова',
            Birthday:new Date(2004, 4, 3),
            StartYear:2020,
            Faculty:'Химия',
        },
        
    
    ]
    
    
    
    
    function formatDate(date){
    
        var dd = date.getDate();
        if (dd < 10) dd = '0' + dd;
    
        var mm = date.getMonth() + 1;
        if(mm < 10 ) mm = '0' + mm;
    
        var yy = date.getFullYear();
        if(yy < 10) yy = '0' + yy;
    
        return dd + '.' + mm + '.' + yy;
    }
    
    
    
    
    function $getNewStudentPerson(stuObj) {
        const $person = document.createElement('tr');
        const $FIO = document.createElement('td');
        const $Bithday = document.createElement('td');
        const $Start = document.createElement('td');
        const $Faculty = document.createElement('td');
    
        $FIO.textContent = stuObj.Surname + ' ' + stuObj.Name + ' ' + stuObj.LastName;
        $Bithday.textContent = formatDate(stuObj.Birthday);
        $Start.textContent = stuObj.StartYear;
        $Faculty.textContent = stuObj.Faculty;
    
        $person.append($FIO, $Bithday, $Start, $Faculty);
        return $person;
    }
    
    function getSortStudents(column, dir, studentsArray) {
        const studentsCopy = [...studentsArray];
        return studentsCopy.sort(function (studentA, studentB) {
            const valueA = studentA[column];
            const valueB = studentB[column];
    
            if (column === 'Birthday' || column === 'StartYear') {
                return dir ? valueA - valueB : valueB - valueA;
            }
    
            if (column === 'Faculty') {
                const facultyA = (valueA === undefined) ? '' : valueA.toLowerCase();
                const facultyB = (valueB === undefined) ? '' : valueB.toLowerCase();
                return dir ? facultyA.localeCompare(facultyB) : facultyB.localeCompare(facultyA);
            }
    
            if (typeof valueA === 'undefined' || valueA === null) {
                return dir ? 1 : -1;
            }
    
            if (typeof valueB === 'undefined' || valueB === null) {
                return dir ? -1 : 1;
            }
    
            return dir ? valueA.localeCompare(valueB) : valueB.localeCompare(valueA);
        });
    }
    
    let column = 'fio';
    let columnDir = true;
    
    Object.defineProperty(Object.prototype, 'fio', {
        get: function () {
            return this.Surname + ' ' + this.Name + ' ' + this.LastName;
        },
        enumerable: true,
    });
    
    function applyFilters() {
        let filteredStudents = [...students];
    
        const nameFilter = (document.getElementById('name-filter')?.value) || '';
        const lastNameFilter = (document.getElementById('lastname-filter')?.value) || '';
        const facultyFilter = (document.getElementById('faculty-filter')?.value) || '';
    
        if (nameFilter) {
            filteredStudents = filteredStudents.filter(student => student.fio.toLowerCase().includes(nameFilter.toLowerCase()));
        }
    
        if (lastNameFilter) {
            filteredStudents = filteredStudents.filter(student => student.fio.toLowerCase().includes(lastNameFilter.toLowerCase()));
        }
    
        if (facultyFilter) {
            filteredStudents = filteredStudents.filter(student => student.Faculty.toLowerCase().includes(facultyFilter.toLowerCase()));
        }
    
        return filteredStudents;
    }
    
    function clearFilters() {
        const nameFilterInput = document.getElementById('name-filter');
        const lastNameFilterInput = document.getElementById('lastname-filter');
        const facultyFilterInput = document.getElementById('faculty-filter');
    
        if (nameFilterInput) {
            nameFilterInput.value = '';
        }
    
        if (lastNameFilterInput) {
            lastNameFilterInput.value = '';
        }
    
        if (facultyFilterInput) {
            facultyFilterInput.value = '';
        }
    }
    
    document.getElementById('name-filter').addEventListener('input', function () {
        render(applyFilters());
    });
    
    document.getElementById('faculty-filter').addEventListener('input', function () {
        render(applyFilters());
    });
    
    document.getElementById('start-year-filter').addEventListener('input', function () {
        render(applyFilters());
    });
    
    document.getElementById('finish-year-filter').addEventListener('input', function () {
        render(applyFilters());
    });
    function getFromLocalStorage() {
        const storedData = localStorage.getItem('students');
        return storedData ? JSON.parse(storedData) : [];
    }
    
    let information = getFromLocalStorage();
    
    window.addEventListener('load', function() {
        information = getFromLocalStorage();
        render(information);
    });
    
    
    function render(arr = students) {
        const copyArr = [...arr];
        const $studentList = document.getElementById('student-list');
        const $studentListTHAll = document.querySelectorAll('.table-student th');
    
        $studentList.innerHTML = '';
    
        for (const stuObj of copyArr) {
            const $newPerson = $getNewStudentPerson(stuObj);
            $studentList.appendChild($newPerson);
        }
    
        $studentListTHAll.forEach((element) => {
            element.addEventListener('click', function () {
                const column = this.dataset.column;
                columnDir = !columnDir;
                render(getSortStudents(column, columnDir, students));
            });
        });
    }
    
    document.getElementById('reset-filter').addEventListener('click', function () {
        clearFilters();
        render(students);
    });
    
    document.getElementById('form-add').addEventListener('submit', function (event) {
        event.preventDefault();
    
        let newListObj = {
            Name: document.getElementById('name').value,
            LastName: document.getElementById('lastname').value,
            Surname: document.getElementById('surname').value,
            Birthday: new Date(document.getElementById('birthday').value),
            StartYear: document.getElementById('startYear').value,
            Faculty: document.getElementById('faculty').value,
        };
    
        // Добавляем нового студента в массив
        students.push(newListObj);
    
        // Сохраняем обновленный массив в локальное хранилище
        saveToLocalStorage(students);
    
        // Перерисовываем таблицу
        render(getSortStudents(column, columnDir, applyFilters()));
    
        clearFilters();
    });
    
    // Функция для сохранения данных в локальное хранилище
    function saveToLocalStorage(data) {
        localStorage.setItem('students', JSON.stringify(data));
    }
    getFromLocalStorage(students);
     //render(getFromLocalStorage());
    // Получаем данные из локального хранилища и отрисовываем их
    render(students);

вот консоль выдал ошибки

main.js:55 Uncaught TypeError: date.getDate is not a function
    at formatDate (main.js:55:19)
    at $getNewStudentPerson (main.js:78:28)
    at render (main.js:200:28)
    at main.js:188:5