Javascript 节点JS mysql数据库断开连接

我正在使用NodeJS，我正在尝试连接到mysql数据库。由于超时，它不断断开连接，因此我编写了一个函数，以便在超时时重新连接。虽然我需要它是一个连续的连接，但代码中的引用将不起作用。这是我的相关代码：

var mysql = require('mysql');
var connection = mysql.createConnection({
    host     : '.........', // MySQL Host
    user     : '.........', // MySQL User
    password : '.........', // MySQL Password
    database : '.........' // MySQL Databse
});

// MYSQL INFO

//connection.connect();

function replaceClientOnDisconnect(connection) {
  connection.on("error", function (err) {
    if (!err.fatal) {
      console.log('Databse Error, error not fatal');
      return;
    }

    if (err.code !== "PROTOCOL_CONNECTION_LOST") {
      throw err;
      console.log('PROTOCOL_CONNECTION_LOST Error: Reconnecting to database...');
    }

    setTimeout(function () {
        connection.destroy();
        connection = mysql.createConnection(connection.config);
        replaceClientOnDisconnect(connection);
        connection.connect(function (error) {
          if (error) {
            process.exit(1);
          } else {
              console.log('Reconnected to database!');
          }
    }, 1000); // 1 sec
    });
  });
}

// And run this on every connection as soon as it is created.
replaceClientOnDisconnect(connection);

你可以使用样品

var dbConfig = {
        host: '----',
        user: '----',
        password: '----',
        database: '----',
        port: ----
    };

var connection;
function handleDisconnect() {
    connection = mysql.createConnection(dbConfig);  // Recreate the connection, since the old one cannot be reused.
    connection.connect( function onConnect(err) {   // The server is either down
        if (err) {                                  // or restarting (takes a while sometimes).
            console.log('error when connecting to db:', err);
            setTimeout(handleDisconnect, 10000);    // We introduce a delay before attempting to reconnect,
        }                                           // to avoid a hot loop, and to allow our node script to
    });                                             // process asynchronous requests in the meantime.
                                                    // If you're also serving http, display a 503 error.
    connection.on('error', function onError(err) {
        console.log('db error', err);
        if (err.code == 'PROTOCOL_CONNECTION_LOST') {   // Connection to the MySQL server is usually
            handleDisconnect();                         // lost due to either server restart, or a
        } else {                                        // connnection idle timeout (the wait_timeout
            throw err;                                  // server variable configures this)
        }
    });
}
handleDisconnect();