Javascript 收到此错误时的反应："；[未经处理的承诺拒绝：SyntaxError:JSON解析错误：意外标识符“Employee”；

我正在尝试对json格式进行字符串化，以便在json的post请求体中发送它。我得到一个错误，说：

[Unhandled promise rejection: SyntaxError: JSON Parse error: Unexpected identifier "Employee"]
* [native code]:null in parse
- node_modules\promise\setimmediate\core.js:37:14 in tryCallOne
- node_modules\promise\setimmediate\core.js:123:25 in setImmediate$argument_0
- node_modules\react-native\Libraries\Core\Timers\JSTimers.js:146:14 in _callTimer
- node_modules\react-native\Libraries\Core\Timers\JSTimers.js:194:17 in _callImmediatesPass
- node_modules\react-native\Libraries\Core\Timers\JSTimers.js:458:30 in callImmediates
* [native code]:null in callImmediates
- node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:407:6 in __callImmediates
- node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:143:6 in __guard$argument_0
- node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:384:10 in __guard
- node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:142:17 in __guard$argument_0
* [native code]:null in flushedQueue
* [native code]:null in invokeCallbackAndReturnFlushedQueue

下面是我的代码：

const CreateEmployee = () => {
  const [name, setName] = useState("");
  const [email, setEmail] = useState("");
  const [phone, setPhone] = useState("");
  const [salary, setSalary] = useState("");
  const [picture, setPicture] = useState("");
  const [position, setPosition] = useState("");
  const [modal, setModal] = useState(false);
  let body = JSON.stringify({
    name: name,
    email: email,
    phone: phone,
    salary: salary,
    picture: picture,
    position: position,
  });
  const submitData = () => {
    fetch("http://94413b3f3960.ngrok.io/send-data", {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
      },
      body: body,
    }).then((res) => res.json());
    // .then((data) => console.log(data));
  };

我尝试将JSON字符串化后打印出来，结果打印正确，如下所示：

{"name":"Oma","email":"Dj","phone":"Fey","salary":"Jdd","picture":"","position":"Jjx"}

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文本值是由一些文本输入测试的随机输入

听起来像服务器不返回JSON？听起来像服务器不返回JSON？