Why is the numeric variable received via Ajax not printed?

Question

AJAX

function getAjaxResult(url,data=null){
  var res;
  $.get(
        url,
        {data:data},
        function (result) {
            res=result;
        },
        "json"
    );
    return res;
}
$('.btn').click(function(){
alert(getAjaxResult('/get_products_select_count',null));
    });

outputs undefined or NaN if you insert + before getAjaxResult, even though the script at '/get_products_select_count' actually returns the number 2. What's the problem here?

Answer 1

function getAjaxResult(url, data = null) {
    return $.get(url, { data });
}

$('.btn').click(function () {
    getAjaxResult('/get_products_select_count').then(function (data) {
        alert(data);
    });
});

$('.btn').click(async function () {
    const data = await getAjaxResult('/get_products_select_count');
    alert(data);
});

Answer 2

Asynchrony. The $.get function finishes executing as soon as the request is sent to the server. An anonymous callback is called after the response to the request has arrived.