您可以在选项之间循环以获取隐藏选项的计数，然后根据显示消息来检查“隐藏总数”和“隐藏总数”选项是否相同。
演示代码：

var date = $("#date");
var count = 0;
$('.js-check-in-times option').each(function() {
  if ($(this).css("display") == "none") {
    count++;
  }
})
console.log(count)
// Show the date only if there are open spots
if ($('.js-check-in-times option').length === count) {
  date.html('');
} else {
  date.html('Working now.');
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.0.0/jquery.min.js"></script>
<select class="check-in__select js-check-in-times" id="time" name="AptTime" required="" aria-required="true" aria-label="times filter">
  <option value="2021-07-28T08:15:00.000-04:00" data-group="2021-07-28" style="display: none;">08:15 AM</option>
  <option value="2021-07-28T08:30:00.000-04:00" data-group="2021-07-28" style="display: none;">08:30 AM</option>
  <option value="2021-07-28T08:45:00.000-04:00" data-group="2021-07-28" style="">08:45 AM</option>
</select>

<div id="date" style="font-size: 24px; color: red; font-family: sans-serif;"></div>

您可以选择所有选项，然后获取样式属性并选中
检查样式是否为空

var date = $("#date");
var sel = $("#time");
var opts = sel.find("option");

for(var opt of opts) {
    if($(opt).attr("style") !== undefined && $(opt).attr("style") === "") {
        date.html("There's Element Haven't Style");
    } else {
        date.html('Working now.');
    }
}

检查是否仅显示可见选项及其样式

var date = $("#date");
var sel = $("#time");
var opts = sel.find("option");

for(var opt of opts) {
    if($(opt).css("display") !== "none" && $(opt).attr("style") !== undefined && $(opt).attr("style") === "") {
        date.html("There's Element Haven't Style");
    } else {
        date.html('Working now.');
    }
}

滤器 options 基于 style 属性
如果缺少样式属性，请与进行比较 null 而不是 '' ```
var date = $("#date");

// Show the date only if there are open spots
var optionsWithEmptyStyle = $('.js-check-in-times option').filter(function() {
return $(this).attr('style') === '';
});

if (optionsWithEmptyStyle.length === 0) {
date.html('');
} else {
date.html('Working now.');
}