Question

几天前我正在学习NodeJS。我在arduino中制作了Modbus TCP通信器程序。我用mariaDB制作了一个NodeJs服务器。我从许多github示例资源中获得了一些代码。（例如，node-modbus，mariadb）但是当我混合他们的代码时，问题开始出现。我只是想在数据库中插入数据。我试图创建变量，然后将代码放入setInterval函数中。但是失败了。我有两个代码。

 client.on('connect', function () {
 setInterval( function () {
 client.readHoldingRegisters(0, 125).then((response) => 
 console.log(response.payload))
 asyncFunction();
 }, time_interval) /* reading coils every second */
 })"


 const mariadb = require('mariadb');
 const pool = mariadb.createPool({host: '127.0.0.1', port:3306, user: 
 'root', password:'###', database:'test',connectionLimit: 5});

 async function asyncFunction() {
 let conn;
 try {
 conn = await pool.getConnection();
 const rows = await conn.query("SELECT * from test.egtest");
 console.log(rows); //[ {val: 1}, meta: ... ]
 const res = await conn.query("INSERT INTO test.egtest value (?, ?)", [1, 
 "mariadb"]);
 console.log(res); // { affectedRows: 1, insertId: 1, warningStatus: 0 }

 } catch (err) {
 throw err;
 } finally {
  if (conn) return conn.end();
  }
 }

var data_result;
client.on('connect', function () {
setInterval( function () {
 client.readHoldingRegisters(0, 125).then((response) => 
console.log(response.payload))
data_result= response.payload;
 asyncFunction();

 }, time_interval) /* reading coils every second */
})"
const mariadb = require('mariadb');
const pool = mariadb.createPool({host: '127.0.0.1', port:3306, user: 'root', password:'###', database:'test',connectionLimit: 5});

async function asyncFunction() {
  let conn;
  try {
    conn = await pool.getConnection();
    const rows = await conn.query("SELECT * from test.egtest");
    console.log(rows); //[ {val: 1}, meta: ... ]
    const res = await conn.query("INSERT INTO test.egtest value (?, ?)", [1, data_result]);
    console.log(res); // { affectedRows: 1, insertId: 1, warningStatus: 0 }

  } catch (err) {
    throw err;
  } finally {
    if (conn) return conn.end();
  }
}

现在NodeJS显示错误“未定义响应”，我正在尝试放入一些C或JAVA语言代码。也许这是不一样的语言。我该如何解决？以及如何学习javasciprt的基本语法？

如何解决一些javascript基本语法问题

0 个答案: