尝试将 ajax 与 select2 一起使用时出错

Question

知道如何调试 select2 的 ajax 功能吗？这是我正在尝试实现的示例：https://jsbin.com/sohupoviko/edit?html,output 和 这是http://localhost:4000/users 的结果集：

[
  {
    "id": 1,
    "first_name": "John",
    "last_name": "Smith"
  },
  {
    "id": 2,
    "first_name": "John2",
    "last_name": "Smith2"
  }
]

这是我在本地运行代码时返回的本地错误：

jquery.min.js:2 jQuery.Deferred exception: Cannot read property 'length' of undefined TypeError: Cannot read property 'length' of undefined
    at d (https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/js/select2.min.js:2:5214)
    at Object.f.transport.d.status.0.d.status.e.trigger.message (https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/js/select2.min.js:2:4227)
    at j (http://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js:2:29948)
    at k (http://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js:2:30262) undefined

知道根本原因是什么或如何调试吗？

Answer 1

在您的后端代码中，请更改您的查询以使用 "AS TEXT"

例子：

$query = $mysqli->query("SELECT id, first_name, last_name AS text FROM users WHERE fist_name LIKE '%$term%'"));
while ($row = mysql_fetch_assoc($query)) {
       $return[] = $row;
     }

echo json_encode($return);

归功于 -> Select2.js error: Cannot read property 'length' of undefined