我很难理解我在这个POST请求上做错了什么。POST请求本身正在工作-在网络选项卡中确认。但是，我只能发布我定义的静态值，而不是来自表单字段的值。请看一看。这让我很恼火。谢谢!
注：

• 在TestForm.js中，它实际上似乎并不像我要求的那样记录响应。
• 我没有收到任何错误。
• 这确实会POST到我的服务器和Postgres中，我将在下面显示当我使用console.log时的情况。
• handleSubmit开头的console.log（sauces）实际上正确地显示了"sauces"，这是输入到第一个表单字段中的任何内容。
• Project GitHub

React表单组件（TestForm.js）：

function TestForm() {
  const [sauce, setSauce] = useState('');
  const [presentation, setPresentation] = useState('');

  const handleSubmit = (e) => { 
    e.preventDefault();
    fetch('http://jyh:3000', {
      method: 'POST',
      headers: {'Content-Type':'application/json'},
      body: JSON.stringify({
        "test_name": sauce,
        "test_sauce": presentation,
      }),
      }).then((res) => {
        console.log(res.json());
        return res.json();
      }).catch((err) => {
          console.log(err.message);
      });
    };

  return (
    <form onSubmit={handleSubmit}>
      <div className="color-section" id="reviewASauce">
        <div className="container-fluid">
          <h2>Review a Sauce</h2><br />
            Trying a sauce that is already in our database? Review it!
            <br />
            <br />
            <br />
            <h2>Sauce Name</h2>
          <Form.Label htmlFor="test_name">
            </Form.Label>
          <Form.Control
            type="text"
            id="test_name"
            aria-describedby="test_name"
            placeholder="Input the name of the sauce here."
            value={sauce}
            onChange={(e) => setSauce(e.target.value)}
          />
          <Form.Text id="test_name" muted>
          </Form.Text>

          <br />
          <br />

          <Form.Label htmlFor="test_sauce">
            </Form.Label>
          <Form.Control
            type="text"
            id="test_sauce"
            aria-describedby="test_sauce"
            placeholder="Input the name of the sauce here."
            value={presentation}
            onChange={(e) => setPresentation(e.target.value)}
          />
          <Form.Text id="test_sauce" muted>
          </Form.Text>
        
        <br />
        <br />

        <Button variant="dark" type="submit">
          Submit
        </Button>
        </div>
      </div>
    </form>
  );
}

export default TestForm;

服务器索引. js：

app.post('/', async (req, res) => {
    await TestTable.create({
            test_name: "test_name",
            test_sauce: "test_sauce",
        }).then((data) => {
            console.log(data.toJSON());
        }).catch((err) => {
            console.log(err);
        });
    });

点击提交时终端显示的内容：

{
  id: 100,
  test_name: 'test_name',
  test_sauce: 'test_sauce',
  updatedAt: 2022-12-21T02:54:42.447Z,
  createdAt: 2022-12-21T02:54:42.447Z
}

I have tried to change and arrange both the HandleSubmit function as well as my app.post, but no matter what I do I cannot seem to get the form data from TestForm.js to index.js.
What form looks like on front end