async each is running to fast? - node.js

Question

I have the following code running through an object with async:
async.each(Object.keys(shopList), function(key, callback){
var shop = shopList[key];
saveOrder(payId, shopList[key], key, req.body, req.user, function(err, newOrder){
if (err) {
callback(err);
}else{
orderCount++;
console.log("succes!", orderCount, newOrder.number);
callback();
}
})
}, function(err){
if (err) {
console.log("ERROR!", err);
}else{
console.log("done!");
}
})
In this function a another function is called. This code looks like this:
saveOrder = function(payId, shop, nameSlug, body, user, callback){
console.log("saveOrder");
var orderNumber = 0;
Order.findOne().sort({_id:-1}).exec(function(err, latestOrder) {
if(latestOrder.number){
orderNumber = latestOrder.number.split("-")[1];
}
var order = new Order();
var date = new Date();
order.number = date.getFullYear().toString() + date.getMonth().toString() + "-" + (parseInt(orderNumber)+1);
order.date = date;
order.payId = payId;
order.status = {
status: "Created",
comment: "",
date: new Date()
};
order.comment = body.comment;
order.shop = {
name: shop.name,
nameSlug: nameSlug
}
order.billingDetails = {
//order details
}
order.sendDetails = {
//more order details
}
order.user = {
//yep, order details
}
var orderItems = [];
for(p = 0; p < shop.items.length; p++){
var product = shop.items[p];
var orderItem = {
_id: product._id,
name: product.name,
brand: product.brand[0].name,
price: product.price,
quantity: product.quantity
}
orderItems.push(orderItem);
}
order.items = orderItems;
order.save(function(err, result){
if (err){
console.log("err!", err);
return callback(err)
}else{
console.log("saved!");
return callback(null, result);
}
})
})
}
The problem is in the last function. There I try to create a ordernumber which must be unique. I get the last order, split the ordernumber and do a +1.
When I have more objects in my shopList, this function is triggered when he is not ready. With other words, the first order isn't saved then, and I will get the same ordernumber.
How can I fix this? I tried a setTimeout in the async.each but that isn't working.

Answer 1

You could use a mutex using locks.
The callbacks will wait that the mutex is unlocked to lock it making that you won't have simultaneous executions.
var locks = require('locks');
var mutex = locks.createMutex();
saveOrder = function(payId, shop, nameSlug, body, user, callback){
mutex.lock(function () {
console.log("saveOrder");
var orderNumber = 0;
Order.findOne().sort({_id:-1}).exec(function(err, latestOrder) {
if(latestOrder.number){
orderNumber = latestOrder.number.split("-")[1];
}
var order = new Order();
var date = new Date();
order.number = date.getFullYear().toString() + date.getMonth().toString() + "-" + (parseInt(orderNumber)+1);
order.date = date;
order.payId = payId;
order.status = {
status: "Created",
comment: "",
date: new Date()
};
order.comment = body.comment;
order.shop = {
name: shop.name,
nameSlug: nameSlug
}
order.billingDetails = {
//order details
}
order.sendDetails = {
//more order details
}
order.user = {
//yep, order details
}
var orderItems = [];
for(p = 0; p < shop.items.length; p++){
var product = shop.items[p];
var orderItem = {
_id: product._id,
name: product.name,
brand: product.brand[0].name,
price: product.price,
quantity: product.quantity
}
orderItems.push(orderItem);
}
order.items = orderItems;
order.save(function(err, result){
if (err){
console.log("err!", err);
return callback(err)
}else{
console.log("saved!");
return callback(null, result);
}
})
})
mutex.unlock(); //don't forget to unlock the mutex
});
}

Answer 2

You should use async.waterfall instead of async.each, because:
async.waterfall - runs the tasks array of functions in series, each passing their results to the next in the array. http://caolan.github.io/async/docs.html#waterfall
async.each - applies the function iteratee to each item in coll, in parallel.

Answer 3

Fixed this issue with using eachSeries() instead of each()
http://caolan.github.io/async/docs.html#eachSeries