Node help! Why this require works inside arrow function but no outside of it?


  • I'm geting DB is not a constructor for the following code. If I move the const DB = require("./db"); inside the mysql() arrow function then it works. But I can't understand why...

    const winston = require("winston");
    const DB      = require("./db");
    
    let logger  = winston.createLogger(
    {
        format: winston.format.json(),
        transports: [
          new winston.transports.File({
              filename: 'logs.txt'}),
    
          new winston.transports.Console({
            format: winston.format.colorize()})
        ]
    
    });
    
    
    logger.mysql = (level, msg, filename, stack)=>
    {
    
        //Create the database object.
        const db = new DB();
    
        //Open the connection.
        db.open().then((result)=>
        {
            db.conn.query(`INSERT INTO t_logs (m_level, m_msg, m_filename, m_stack) 
            VALUES (?, ?, ?, ?);`, [level, msg, filename, stack], (err)=>
            {
                //Something went wrong.
                if (err)
                    logger.error(err.stack);
    
                //Close the connection.
                db.close().catch((e)=>logger.error(e.stack));
            });
        })
        .catch((e)=>
        {
            logger.error(e.stack);
        });
    };
    
    
    module.exports = logger;
    
  • GNU/Linux Admin

    FWIW, I should mention that this is a forum for community discussion for NodeBB, the forum software, not for Node.js 😄


  • @babaliaris who is calling the logger.mysql () function... probably a browser.. but the CONST DB was done in the main process I would guess..

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