TypeError: (intermediate value) is not iterable

I turn my code to class, it now return some error. that i dont know what is this. i tested already without wrapper into class, the code working. what is this exactly?

TypeError: (intermediate value) is not iterable

const mysql = require('mysql2');
const options = require('../config/database');

class Mysql
{
    pool;

    createPool(options)
    {
        this.pool = mysql.createPool(options).promise();
    }

    async execute(query, parameter)
    {
        try 
        {
            const [rows,fields] = this.pool.execute(query, parameter);

            return [rows,fields];
        }catch(e)
        { 
            console.log(e.code);
        }      
    }
}

const client = new Mysql;

client.createPool(options);

(async () => {
  const [rows] = await client.execute("SELECT * FROM media");

  console.log(rows);
})();