实现异步/等待node.js和mysql

Question

I need to do a truncate of a table and then wait to start populate again, I must implement async/await otherwise is not working good.

How can I do this? I try with await on truncateCharfileWorldSaveTable and using async on that function but I don't understand how to make it work.

async function truncateCharfileWorldSaveTable(){
    let query = 'TRUNCATE charfiles_worldsave'

    await db.get().query(query, function (err, result, fields) {
        if (err) console.error('function truncateCharfileWorldSaveTable: ' + err);
        console.info('Tabla charfiles_worldsave_temporal TRUNCATE');
    });
}

exports.backupCharfiles = async function(req, res) {
    try {

        //Primero borramos todo el contenido de la tabla e iniciamos el proceso
        await truncateCharfileWorldSaveTable()

        console.info('==== INICIANDO COPIA DE CHARFILES POR WORLDSAVE ======')
        let files = fs.readdirSync('./charfiles/');
        files = files.filter(file => file.endsWith('.chr'));
        files.forEach(writeCharfileWorldSaveTable)
        res.status(200).send('Se estan guardando los charfiles en la base de datos');

    } catch(err) {
        console.error('function backupCharfiles: ' + err)
    }
};

Answer 1

awaiting a function that takes callbacks does nothing. await needs a promise to work, and if you want to convert a callback-based function to Promise style function util.promisfy might help here.

However, there's also the mysql2 package, which is pretty great. You can require mysql2/promise instead of mysql which will turn all callback-based functions into awaitable promise-style functions.