<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1">


</head>

<body>
  <ul id="myList">
    <li id="item1">项目 1</li>
    <li id="item3">项目 3</li>
    <li id="item2">项目 2</li>
    <li id="item4">项目 4</li>
  </ul>

  <script>
    function sortAndReturnTextContent() {
      const items = document.getElementById('myList').children;
      // 在此补全代码
      const arr = Array.from(items).map((item) => ({ id: item.id.replace('item', ''), text: item.innerText }))
        console.log(arr)
        arr.sort((a, b) => a.id - b.id)
        let str = arr.reduce((prev, curr) => `${prev}<li id='item${curr.id}'>${curr.text}</li>`, '')
        console.log(str)
        document.getElementById('myList').innerHTML = str
    }
    sortAndReturnTextContent()
  </script>



</body>

</html>