javascript - 获取 jquery 和 ecmascript6 中的最高属性编号

Question

尝试获取具有相同数据属性的所有选择的最大值。但收到错误

{ "message": "Uncaught TypeError: undefined is not a function",
"filename": "https://stacksnippets.net/js", "lineno": 37, "colno": 34 }

请运行下面的代码片段，我希望它能够输出 3，因为这是问题 ID 为 1 的最高响应组编号

$(document).ready(function() {
  let question = {
    Id: 1
  };

  let responseGroupNumber = Math.max(...$(`select[data-questionid = ${question.Id}]`)
    .map(x => $(x)
      .attr('data-responsegroupnumber')));

  console.log(responseGroupNumber);

});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<select data-questionid="1" data-responsegroupnumber="1">
  <option>one</option>
  <option>two</option>
  <option>three</option>
</select>


<select data-questionid="1" data-responsegroupnumber="2">
  <option>one</option>
  <option>two</option>
  <option>three</option>
</select>

<select data-questionid="1" data-responsegroupnumber="3">
  <option>one</option>
  <option>two</option>
  <option>three</option>
</select>

Answer 1

您需要使用 jQuery .get()映射前的函数:

如果不这样做，您将使用 jQuery .map()方法而不是 Array#map

$(document).ready(function() {
  let question = {
    Id: 1
  };
  
  let responseGroupNumber = Math.max(...$(`select[data-questionid = ${question.Id}]`).get().map(x => $(x).attr('data-responsegroupnumber')));
  console.log(responseGroupNumber);
  
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<select data-questionid="1" data-responsegroupnumber="1">
  <option>one</option>
  <option>two</option>
  <option>three</option>
</select>


<select data-questionid="1" data-responsegroupnumber="2">
  <option>one</option>
  <option>two</option>
  <option>three</option>
</select>

<select data-questionid="1" data-responsegroupnumber="3">
  <option>one</option>
  <option>two</option>
  <option>three</option>
</select>