Newbie async.waterfall - node.js

Question

I tried use async.
I have a rout function with a async.waterfall.
The 1st function call an external function and fetch all users in usersData
The 2nd function, via async.each, it call an external function to search infos for each user.
I want pass again usersData with the news values to the 3th function.
In the 3th function, for the moment, I have a async.each and I watch the datas for each user.
My issues
1) In the second function, I don't fetch the information for each user.
2) The 3th function is called before the 2nd and I don't fetch the new data
Thanks
router.post('/launch',function(req,res,next){
async.waterfall([
function(cb){
// fetch the global users
fetchUsers(usersData,cb);
},
function(usersData,cb){
async.each(usersData,
function(userdata,cb){
// fetch other data for each user
calcBalance(userdata, cb);
},function(err){
cb(err,usersData);
});
},
function(usersData,cb){
async.each(usersData,
function(userdata,cb) {
//watch the info with the news data
console.log(' 2 '+ JSON.stringify(userdata));
//console.log(3);
}
);
},
],
function(err,results){
console.log('Fin' + JSON.stringify(results));
res.render('synchros',{launch:'end'},results);
});
res.render('synchros',{launch:'end'});
});
function calcBalance(userData,cb){
var user_id=userData.id,
resultCalcBalance=0,
cats_id=[3,4,6],
tabData={};
async.each(cats_id,function(cat_id,cb){
switch (cat_id) {
case 3:
var comp = "<=";
break;
case 4:
var comp = "<=";
break;
case 6:
var comp = "<";
break;
}// fin du switch
var myquery = "select blabla+
//console.log(calcul_balance);
connectionMysql.query(myquery, function (err, rows, fields,cb) {
if (err) {
console.log('Error ' + err);
cb(err);
}
else if (rows.length != 0) {
if (rows != 0) {
}// end if
else {
}// end else
}); // end connectionMysql
},function(err){
cb(err,userData); // ?? I send the data here
});
cb(null, userData); // ?? I send the data here ??
}

Answer 1

I reindented, fixed some typos, and changed the names of the callbacks. I changed the second async.each to async.map because you're processing an array to get a set of one result per item.
The first problem was in the second to last line. You were calling back too early from calcBalance.
Another potential problem was an ambiguous callback name cb in the second waterfall function (as well as in calcBalance.)
Finally, you never ran the async.each callback in the third waterfall function, and if you calledback out of it, it was accidental.
You still aren't ever reporting success from one database query, so you will need to call done() if it worked. You might also want to use async.map for the database calls, this would let you assemble the results, like done(null, balanceForCategory)
router.post('/launch', function(req, res, next){
async.waterfall([
function(done){
// fetch the global users
fetchUsers(usersData,done);
},
function(usersData,done){
async.map(usersData, function(userdata, done2){
// fetch other data for each user
calcBalance(userdata, done2);
},function(err, results){
done(err,usersData);
});
},
function(usersData, done){
async.each(usersData, function(userdata, done2) {
//watch the info with the news data
console.log(' 2 '+ JSON.stringify(userdata));
//console.log(3);
}, done)
},
],
function(err, results){
// results will be undefined because we called done() from the above async.each
console.log('Fin' + JSON.stringify(results));
res.render('synchros', {launch:'end'}, results);
}); // end of async.each
}); // end of router.post()
function calcBalance(userData, callback){
var user_id=userData.id,
resultCalcBalance=0,
cats_id=[3,4,6],
tabData={};
async.each(cats_id, function(cat_id, done){
switch (cat_id) {
case 3:
var comp = "<=";
break;
case 4:
var comp = "<=";
break;
case 6:
var comp = "<";
break;
}// fin du switch
var myquery = "select blabla";
//console.log(calcul_balance);
connectionMysql.query(myquery, function (err, rows, fields, queryCb) { // what is this queryCb param?
if (err) {
console.log('Error ' + err);
queryCb(err); // This will callback whatever mySql passed in as queryCb
// done(err) // This will callback out of the async.each iterator and immediately the async.each callback
// callback(err) // This will callback out of calcBalance and continue executing
// return callback(err); // This will callback out of calcBalance and stop executing
} else if (rows.length != 0) {
if (rows != 0) {
// Your code might hang here without calling a callback
} else {
// Your code might hang here without calling a callback
}
}); // end connectionMysql
},function(err){
// Inside async.each callback. Either everything worked or something broke
callback(err,userData); // Send the data back out of calcBalance
});
//callback(null, userData); // Running this here will IMMEDIATELY call back before async.each runs
}

Answer 2

The calcBalance function
function calcBalance(userData,callback){
// Ensuite on va calculer les rtt_balances et holiday_balances et yesterday_extra_hours_month
var user_id=userData.id,
resultCalcBalance=0,
cats_id=[3,4,6],
tabData={},
dateJour=moment().format('YYYY-M-D');;
async.each(cats_id,function(cat_id,done){
switch (cat_id) {
case 3:
var comp = "<=";
break;
case 4:
var comp = "<=";
break;
case 6:
var comp = "<";
break;
}// fin du switch
var calcul_balance = "select * from table1"
connectionMysql.query(calcul_balance, function (err, rows, fields,queryCb) {
if (err) {
queryCb(err); // This will callback whatever mySql passed in as queryCb
// done(err) // This will callback out of the async.each iterator and immediately the async.each callback
// callback(err) // This will callback out of calcBalance and continue executing
// return callback(err); // This will callback out of calcBalance and stop executing
console.log('Error ' + err);
queryCb(err);
}
else if (rows.length != 0) {
if (rows != 0) {
// On va chercher les valuers sinon on les laisse à zéro par défaut.
for (var j = 0; j < rows.length; j++) {
if (!isNaN(rows[j].amount) && rows[j].amount != null) {
resultCalcBalance += parseInt(Math.round(rows[j].amount * 100) / 100);
//console.log('ResultCalculBalance 1chiffre ' + parseInt(Math.round(rows[j].amount*100)/100) + ' 2chiffre' + resultCalcBalance);
} else {
resultCalcBalance += 0;
//console.log('ResultCalculBalance 2' + JSON.stringify(rows[j].amount));
}
} // fin du for k
//console.log('Resultat : ' + userData.id + ' ' + cat_id + ' ' + resultCalcBalance);
if (cat_id == 3) userData.holiday_balance = resultCalcBalance;
if (cat_id == 4) userData.rtt_balance = resultCalcBalance;
if (cat_id == 6) userData.yesterday_extra_hours_month = resultCalcBalance;
}// fin du if
else {
if (cat_id == 3) userData.holiday_balance = 0;
if (cat_id == 4) userData.rtt_balance = 0;
if (cat_id == 6) userData.yesterday_extra_hours_month = 0;
}// fin du else
}// de la condition err ou pas
console.log('1 '+JSON.stringify(userData));
});
},function(err){
callback(err,userData);
});
//callback(null, userData); // Running this here will IMMEDIATELY call back before async.each runs