async module for querying multiple database queries

db.js

const mysql = require("mysql");
const async = require('async')
const dbConfig = require("./tables.js").tables;
const db = mysql.createPool({
  host: "localhost",
  user: dbConfig.username,
  password: dbConfig.password,
  database: "click2magic",
  multipleStatements:true
});
exports.createTables = (obj, cb) => {
  let { dbName, tablesObj } = obj;
  if (!dbName || tablesObj == {}) {
    return false;
  }
  db.getConnection((err, conn) => {
    if (err) {
      console.log(err);
      return cb(handleConnErr(err), false);
    }
    //begin transactions
    conn.beginTransaction(err => {
      if (err) {
          //release connection
          conn.release();
          return console.log(err);
      } //err
      
      async.forEachOf(tablesObj,(value,key,b)=>{
    console.log(db._freeConnections.indexOf(conn))
  if(db._freeConnections.indexOf(conn) != 0){
  let stmt = `CREATE TABLE IF NOT EXISTS ${dbName}.${key} (`;
  let colsObject = value;
  for (colName in colsObject) {
    stmt += `${colName} ${colsObject[colName]},`;
  }
  //remove trailing comma
  stmt = stmt.replace(/,$/,'')+`);`;
  // process.exit();
  conn.query(
    {
      sql: stmt
    },
    function(err, result) {
      if (err) {
        return conn.rollback(() => {
          console.log(err);
          //release connection
          conn.release();
          b(err, false);
        });
      }
      console.log(this.sql);
      
      if (err) return cb(handleConnErr(err));
      if (result.affectedRows) {
        b(null, true);
      } else {
        b(null, false);
      }
    }
  );
     } },err=>{
        //all iterations are done
          if(err) return console.log('async err',err)
          conn.commit((err)=>{
                if(err){
                  return conn.rollback(() => {
                      console.log(err);
                      //release connection
                      conn.release();
                      cb('Error while committing :'+err, false);
                    });
                }
            cb(null,true);
                //
                //release connection
                  conn.release();
            })
      });


      
    });//ends transactions

  });
};

tables.js

exports.tables = {
      users: {
        user_id: "BIGINT PRIMARY KEY AUTO_INCREMENT ",
        user_role: "INT",
        user_name: "VARCHAR(100)",
        user_email: "VARCHAR(100)",
        user_phone: "VARCHAR(10)",
        user_employee_id: "VARCHAR(100)",
        user_good_ratings: "VARCHAR(100)",
        user_bad_ratings: "VARCHAR(100)"
      },
      messages: {
        msg_id: "BIGINT PRIMARY KEY AUTO_INCREMENT ",
        msg_chat_id: "INT",
        msg_by_visitor: "INT",
        msg_timestamp: "TIMESTAMP DEFAULT CURRENT_TIMESTAMP",
        msg_user_id: "VARCHAR(100)",
        msg_visitor_id: "VARCHAR(100)",
        msg_is_transferred_chat: "INT",
        msg_files: "TEXT",
        msg_links: "TEXT"
      },
      visitors: {
        visitor_id: "BIGINT PRIMARY KEY AUTO_INCREMENT ",
        visitor_name: "VARCHAR(100)",
        visitor_email: "VARCHAR(100)",
        visitor_visits: "BIGINT"
      },
      ratings: {
        rating_id: "BIGINT PRIMARY KEY AUTO_INCREMENT ",
        rating_user: "VARCHAR(100)",
        rating_visitor: "VARCHAR(100)",
        rating: "INT"
      },
      app_settings: {
        setting_id: "BIGINT PRIMARY KEY AUTO_INCREMENT ",
        setting_name: "VARCHAR(100)",
        setting_json: "TEXT",
        setting_set_at: "TIMESTAMP DEFAULT CURRENT_TIMESTAMP",
        setting_modified_at: "TIMESTAMP DEFAULT CURRENT_TIMESTAMP"
      },
      chats: {
        chat_id: "BIGINT PRIMARY KEY AUTO_INCREMENT ",
        chat_visitor_id: "VARCHAR(100)",
        chat_response_time: "BIGINT", //seconds
        chat_users: "TEXT", //array of user_ids
        chat_begin_timestamp: "TIMESTAMP DEFAULT CURRENT_TIMESTAMP",
        chat_duration: "BIGINT", //seconds
        chat_triggered_by_user: "INT", //1 || 0
        chat_rating: "INT"
      } //[1-5]
    }