wrapping co and co-mysql from within a generator function, and yielding out of the wrapping function

Question

wrapping co and co-mysql from within a generator function, and yielding out of the wrapping function

I am having trouble understanding co and how to leverage its functionality inside of another generator. Essentially I have a generator that needs to perform a SQL query, then do something complicated with each row before Yielding them out to the calling function (in the of loop).

The someGen code doesn't look right to me, and it isnt working as expected. So my question is twofold. First how can I leverage co-mysql inside of a generator yielding out objects created out of each row. Second I am struggling where to use co, and more importantly why.

No functioning attempt:

const co = require('co')
    , mysql = require('co-mysql')
    , MYSQL_RECORD_SET = 0

let pool = null
let getConnectionPool = function(){
    if(!pool) pool = mysql.createPool(config.db);
    return pool
}

let someGen = function*() {
    co(function*() {
        let connection = getConnectionPool()
        let recordset = yield connection.query('SELECT ? as jobId', [ 99 ]);

        if (recordset && recordset[MYSQL_RECORD_SET]) {
            var jobs = _.map(recordset[MYSQL_RECORD_SET], function (row) {
                return {id: row.jobId }
            })
            yield jobs
        }
    })()
}

for (let job of someGen()) {
    console.log(job)
}

javascript
node.js
generator
co

Answer 1

This is "working" -- but is not what I was originally shooting for. The someGen now executes the query, but returns an array of objects, rather than yielding them individually...

let someGen = function *() {
    let connection = getConnectionPool()
    let recordset = yield connection.query('SELECT ? as jobId', [ 99 ]);
    if (recordset && recordset[MYSQL_RECORD_SET]) {
        return _.map(recordset[MYSQL_RECORD_SET], function (row) {            
            return { jobId: jobId }
        })
    }
}

let runIt = function() {
    var doSomething = function(job){
    }

    co(function*() {
        let jobBatch = yield someGen()
        _.each(jobBatch, function(job){
            doSomething(job) ;
        })
    })()
}

Still looking for a better answer.