我正在学习node.js/express，我试图从头部获取Date值并将其发送到前端。
我似乎不能使用req.getHeader()来做这件事。我也尝试console.log(req)和console.log(req.headers)，但输出与postman中的头不同。
这就是console.log(req.headers)给我的：

{
  'user-agent': 'PostmanRuntime/7.28.0',
  accept: '*/*',
  'cache-control': 'no-cache',
  'postman-token': '6d5acbf2-b63d-46d4-b189-86e163281421',
  host: 'localhost:3001',
  'accept-encoding': 'gzip, deflate, br',
  connection: 'keep-alive'
}

这与 Postman 的标题不同：

下面是我的代码：

const express = require("express");
const app = express();
const cors = require("cors");
const PORT = process.env.PORT || 3001;

app.use(cors());
app.use(express.json());
app.use(express.urlencoded({ extended: true }));

let persons = [
  {
    id: 1,
    name: "Arto Hellas",
    number: "040-123456",
  },
  {
    id: 2,
    name: "Ada Lovelace",
    number: "39-44-5323523",
  },
  {
    id: 3,
    name: "Dan Abramov",
    number: "12-43-234345",
  },
  {
    id: 4,
    name: "Mary Poppendieck",
    number: "39-23-6423122",
  },
];

app.get("/", (req, res) => {
  res.sendFile(__dirname + "/index.html");
});

app.get("/api/persons", (req, res) => {
  res.json(persons);
});

app.get("/api/persons/:id", (req, res) => {
  const id = Number(req.params.id);
  const person = persons.find((person) => person.id === id);
  const unknown = persons.id == "unknown";

  if (person) {
    res.json(person);
  } else {
    res.status(404).end();
  }
});

app.get("/info", (req, res) => {
  let count = persons.length;
  let str = `Phonebook has info for ${count} people.`;

  console.log(req);
  console.log(req.headers);

  let timeDate = req.getHeader(Date); // <-- here is the problem
  console.log(timeDate);
  res.send(`<p>${str} \n ${timeDate}</p>`);
});

app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}`);
});