javascript - jquery 搜索过滤器 - 如果搜索不匹配，选项将被隐藏，但 optgroup 仍显示，如何隐藏 optgroup

Question

在搜索时，如果没有匹配，该选项将被隐藏，但即使没有子选项匹配，optgroup仍然显示。如果没有选项匹配，如何隐藏 optgroup？

我已经尝试过解决这个问题，这是我尝试过的代码:jsfiddle

$("#uniAddressSearch").on("keyup", function (){
   var value = $(this).val().toLowerCase();
     $("#u-address option").filter(function (){
        $(this).toggle($(this).text().toLowerCase().indexOf(value) > -1);
     });
});

// &&

$("#u-address option").each(function() {
  $(this).attr("data-search-term", $(this).text().toLowerCase());
});

$("#uniAddressSearch").on("keyup", function() {
  var searchTerm = $(this).val().toLowerCase();

  $("#u-address option").each(function() {
    if ($(this).filter("[data-search-term *= " + searchTerm + "]").length > 0 || searchTerm.length < 1) {
      $(this).show();
    } else {
      $(this).hide();
    }
  }); //end Option each    
}); //end search

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<div class="address-listing">
    <input type="text" name="addressSearch" id="uniAddressSearch" placeholder="Select Location(s) Individually" class="form-control" />
    </div>
    <div class="u-address-fields">
      <select size="15" multiple="multiple" class="show" id="u-address">
       <optgroup class="og-swe" label="Swedish Cars">
          <option value="volvo">Volvo</option>
          <option value="saab">Saab</option>
       </optgroup>
       <optgroup class="og-ger" label="German Cars">
         <option value="mercedes">Mercedes</option>
         <option value="audi">Audi</option>
         <option value="bmw">BMW</option>
       </optgroup>
       <optgroup  class="og-ita" label="Italian Cars">
         <option value="ferrari">Ferrari</option>
         <option value="lamborghini">Lamborghini</option>
       </optgroup>
     </select>
    </div>

Answer 1

更改这部分代码，

来自:

$("#u-address option").each(function() {
if ($(this).filter("[data-search-term *= " + searchTerm + "]").length > 0 || searchTerm.length < 1) {
  $(this).show();
} else {
  $(this).hide();
}  }); //end Option each   

致:

$("#u-address optgroup").show();
$("#u-address option").each(function() {
if ($(this).filter("[data-search-term *= " + searchTerm + "]").length > 0 || searchTerm.length < 1) {
  $(this).show();
} else {
  $(this).hide();
  var count = $(this).parent("optgroup").find("option:visible").length;
  if(count == 0)
    $(this).parent("optgroup").hide();
}  }); //end Option each