在JScript中将对象序列化为JSON后，为什么会丢失一些字段值？

Question

我按JS中的值填充对象的字段，然后使用fetch方法将其传递给数据库。我可以看到，这些fieldes有正确的值（在控制台中）。但是当我将这个JSON中的对象发送到数据库时，我会丢失这些值。这发生在日期和布尔字段中。为什么会这样？

$imageFolder = public_path("articles/assets/images/");

这是我的功能： function saveAdv（）{

var advToSaveDB = new Object();
var author = new Object();
var rubric = new Object();
$(window).ready(function () {

    var advertisement = JSON.parse(localStorage.getItem('advertisementToEdit'));

    fillAdvFields(advertisement);

    $("#save").click(function () {


        advToSaveDB.id = advertisement.id;
        advToSaveDB.title = $("#title").val();
        advToSaveDB.text = $("#text").val();
        advToSaveDB.price = $("#price").val();
        rubric.id = $(".select").val();
        author.id = advertisement.authorId;
        advToSaveDB.author = author;
        advToSaveDB.rubric = rubric;
        advToSaveDB.date = advertisement.date;

        var check = document.getElementById('myCheck');
        // var closed = false;

        if (check.checked === true) {
            // closed = true;
            advToSaveDB.closed = true;
        }

        console.log(advToSaveDB.closed);//here is true
        console.log(advToSaveDB.date);//here is right value 

        saveAdv();
        $(location).attr('href', 'http://localhost:9999/MyAdvertisements.html?id=1');

    });