createPool is not a function

[chpio]

Hi,

it seams like the createPool function is not defined.

[CodeFoodPixels]

As is stated in the readme, only the standard connection is implemented at the moment. I've not had the chance to implement createPool yet.

On Mon, 22 Jun 2015 12:10 pm t128 notifications@github.com wrote:

Hi,

it seams like the createPool function is not defined.

— Reply to this email directly or view it on GitHub https://github.com/lukeb-uk/node-promise-mysql/issues/6.

[chpio]

oki, im using bluebird directly: https://github.com/petkaantonov/bluebird/blame/4576d0b18d5bff5194d74be5b4530e275c12912e/API.md#L1314-L1325

[edi]

Hello! I'm somewhat new to this whole asynchronous thing, but, bumping into callbacks hell lead me here. So, I just noticed that using the latest node package via npm install promise-mysql I'm still having this issue. In the reply above you stated that only the standard connection is implemented as of yet. Given the fact that it was almost a year ago, I have checked the source code and it actually actualy has a createPool at the moment.

Hence my question.. why am I receiving `mysql.createPool(...).then is not a function.

My implementation looks like this ( again, I'm somewhat new so I might be wrong ).

var mysql = require('promise-mysql'),
    connection,
    DB = function() {
        this.pool = mysql.createPool({ host: 'localhost', user: '', password: '', database: '' }).then(function(conn){
            connection = conn;
        })
    };

DB.prototype.query = function( statement, format, callback ) {
    this.pool.getConnection().then(function( connection ){
        return connection.query( statement, format );
    }).catch(function( err ) {
        console.log( err );
    });
}

module.exports = new DB();

I just tried following the README. Is there something I'm doing wrong, I have also ran npm install bluebird.

What I'm trying to achieve is that, given a route.js file for example, being an express app, I want to do the following:

var db = require( './controllers/DB.js' );
db.query( 'SELECT * FROM users WHERE id = ?', [ user.id ] ).then( rows => {
    console.log( rows )
}); // eventuall chain another promise after this one as well if possible.

Please advise on how would be the correct way to do this. Thank you!

[CodeFoodPixels]

You don't need the . then on the createPool call as this returns a pool object and not a promise. You don't need to install bluebird yourself, it's in the dependencies for the module

[edi]

@lukeb-uk Ok buddy, sorry. I did the modifications.

DB.js looks like the following now:

var DB = function() {
    this.pool = require('promise-mysql').createPool({ db: details });
}
DB.prototype.query = function( sql ) {
    this.pool.getConnection().then( conn => {
        return conn.query( sql ); 
                // I see releaseConnection in the docs but I don't see it ever getting called
    }).catch( err => {
        console.log( err );
    });
}
module.exports = new DB();

Consider this to be my simplifed routes module:

var db = require( './controllers/DB.js' );
db.query( 'SELECT * FROM users WHERE id = 1 LIMIT 1' ).then( rows => {
    console.log( rows )
})

The problem now is that while in my opinion it should work perfectly as conn.query returns a Promise, it actually comes up as TypeError: Cannot read property 'then' of undefined

Doing a console.log( result ) in DB.prototype.query method with a fully valid SQL query, the following comes up on the logs:

Promise {
_bitField: 0,
_fulfillmentHandler0: undefined,
_rejectionHandler0: undefined,
_progressHandler0: undefined,
_promise0: undefined,
_receiver0: undefined,
_settledValue: undefined
}
}

I don't understand what I'm doing wrong... can you shed some light ?

[chpio]

The problem now is that while in my opinion it should work perfectly as conn.query returns a Promise, it actually comes up as TypeError: Cannot read property 'then' of undefined

yeah, you have to return the promise:

DB.prototype.query = function( sql ) {
    return this.pool.getConnection().then( conn => {
        return conn.query( sql ); 
                // I see releaseConnection in the docs but I don't see it ever getting called
    }).catch( err => {
        console.log( err );
    });
}

PS/off topic: also i find async/await much more appealing than normal promises:

async function doAsyncStuff() {
  const rows = await sql.query('SELECT stuff FROM my_table');
  let sum;
  for (const row of rows) {
    sum += row.stuff;
  }
  return sum;
}

[edi]

Ahhh damn, I'm so stupid. I just realized my mindset when it comes to node is trapped into this callback hell. I was returning the query result but not the Promise itself in the query method.

@chpio How to use those ...I get unexpected token function after async..