如何在回调函数中使用表达式response.send (例如，由nodejs中的mysqljs使用)

Question

我在express.If中使用了express和mysqljs --我请求我的数据库来添加一个用户，我必须定义一个回调函数来处理响应。不幸的是，我无法用回调函数来表示res.send，我想将insertID发送到res.send method.How，我要这样做吗？这是我的密码。

app.post("/adduser", (req, res) => {
  const con = mysql.createConnection({
    host: "localhost",
    user: "root",
    password: "",
    database: "customer"
  });
  const name = req.body.name;
  const age = req.body.age;

const users = { name: name, age: age };
  const query = "INSERT INTO users SET ?";
  con.query(query, users, (err, res) => {
    if (err) throw err;
    console.log("Last insert ID:", res.insertId);
    // want to send res.insertId to server
    // res.send() here
  });

}); 

Answer 1

我猜您对“响应”和“结果”都使用了相同的变量名“res”。

正如文档所述，con.query返回“结果”而不是“res”。https://github.com/mysqljs/mysql#performing-queries

app.post("/adduser", (req, res) => {
    const con = mysql.createConnection({
          host: "localhost",
          user: "root",
          password: "",
          database: "customer"
    });
    const name = req.body.name;
    const age = req.body.age;

    const users = { name: name, age: age };
    const query = "INSERT INTO users SET ?";
    con.query(query, users, (err, result) => {
      if (err) throw err;
      console.log("Last insert ID:", result.insertId);
      // want to send result.insertId to server
      // res.send() here

      // res.send(result.insertId); // gives an error
      res.send(result.insertId.toString());
    });

});