Transform mysql 8 data into mongodb;

package.json

{
  "dependencies": {
    "mongodb": "^4.6.0",
    "mysql2": "^2.3.3"
  }
}

transform_mysql_mongo.js

var mysql = require('mysql2');
var MongoClient = require('mongodb').MongoClient;

var mysql_config = {
  host: 'localhost',
  user: 'root',
  password: 'root',
  port: 3306,
  database: 'mysql_db_name',
};
var mongo_uri = 'mongodb://root:root@localhost:27017/?authSource=admin';
var mongo_db_name = 'mongo_db_name';

function getMysqlTables(mysqlConnection, callback) {
  mysqlConnection.query(
    `SELECT table_name FROM information_schema.tables WHERE table_schema = '${mysql_config.database}' ORDER BY table_name`,
    function (error, results, fields) {
      if (error) {
        callback(error);
      } else {
        var tables = results.map((r) => r.TABLE_NAME);
        console.log('total mysql tables:', tables.length);
        callback(null, tables);
      }
    },
  );
}

function tableToCollection(mysqlConnection, tableName, mongoCollection, callback) {
  var sql = 'SELECT * FROM `' + tableName + '`;';
  mysqlConnection.query(sql, function (error, results, fields) {
    console.log('loading data from mysql', tableName, 'result:', !error);
    if (error) {
      callback(error);
    } else {
      console.log('inserting:', tableName, 'records:', results.length);

      if (results.length == 0) {
        results = [
          fields.reduce((acc, f) => {
            acc[f.name] = 'BLANK';
            return acc;
          }, {}),
        ];
      }

      mongoCollection.insertMany(results, {}, function (error) {
        if (error) {
          callback(error);
        } else {
          callback(null);
        }
      });
    }
  });
}

MongoClient.connect(mongo_uri, async function (error, client) {
  if (error) throw error;

  var db = client.db(mongo_db_name);

  var MysqlCon = mysql.createConnection(mysql_config);

  MysqlCon.connect();

  var jobs = 0;

  getMysqlTables(MysqlCon, function (error, tables) {
    tables.forEach(function (table) {
      var collection = db.collection(table);
      ++jobs;
      tableToCollection(MysqlCon, table, collection, function (error) {
        if (error) throw error;
        --jobs;
      });
    });
  });

  console.log('remaining:', jobs);

  var interval = setInterval(function () {
    console.log('remaining:', jobs);
    if (jobs <= 0) {
      clearInterval(interval);
      client.close();
      MysqlCon.end();
      console.log('done!');
      console.log('tap `cmd/ctrl+c` to exit');
    }
  }, 300);
});