nodejs issue with undefined promise nodejs using Q - node.js

Question

I've been wrappingmind over async and sync functions as a php developer ive never had to worry about this much. so my issue is this
i have a function
function loadPartnerInventory(args,itemIds,offers,offer) {
var deferred = Q.defer();
offers.loadPartnerInventory(args, function(err, items) {
var checkItems = [];
var len = items.length;
for(var i = 0; i < itemIds.length; i++) {
for(var j = 0; j < items.length; j++) {
if (itemIds[i] == items[j].id){
//console.log('Pushed: ' + items[j].name);
checkItems.push({
itemname: items[j].market_name,
market_hash_name: items[j].market_hash_name,
steamid: offer.steamid_other,
tradeofferid : offer.tradeofferid
});
}
}
}
deferred.resolve(checkItems);
});
return deferred.promise;
}
function loadMyInventory(args,itemIds_g,offers,offer) {
var deferred = Q.defer();
offers.loadMyInventory(args, function(err, itemsg) {
var checkItems_g = [];
var len = itemsg.length;
for(var i = 0; i < itemIds_g.length; i++) {
for(var j = 0; j < itemsg.length; j++) {
if (itemIds_g[i] == itemsg[j].id){
console.log('Pushed: ' + itemsg[j].name);
checkItems_g.push({
itemname: itemsg[j].market_name,
market_hash_name: itemsg[j].market_hash_name,
steamid: offer.steamid_other,
tradeofferid : offer.tradeofferid
});
}
}
}
deferred.resolve(checkItems_g);
});
return deferred.promise;
}
function getPartnerInventory(offers, offer, itemIds, itemIds_g) {
var p1 = loadPartnerInventory({
partnerSteamId: offer.steamid_other,
appId: 730,
contextId: 2
},itemIds,offers,offer);
var p2 = loadMyInventory({appId: 730, contextId: 2},itemIds_g,offers,offer);
return Q.all(p1, p2).spread(function(checkItems, checkItems_g) {
return {
checkItems: checkItems,
checkItems2: checkItems_g
};
});
}
im doing this to get results, but somehow the second prommiss is undefined and i dont understand why.
getPartnerInventory(offers,offer,itemIds,itemIds_G).then(function(response) {
console.log(response);
//console.log(response);
});
checkitems returns correctly yet checkitems 2 is undefined.
cosole log is :
{ checkItems:
{ itemname: 'Operation Breakout Weapon Case',
market_hash_name: 'Operation Breakout Weapon Case',
steamid: '76561198245431424',
tradeofferid: '859881697' },
checkItems2: undefined }
Pushed: Glock-18 | Wraiths
as can see it its undiefined but seems to add item after its done

Answer 1

You cannot resolve the same promise twice. You should wrap both methods in separate promises and then use Q.all(), which will return a new promise to be resolved only after both promises have been successfully resolved. For example:
function mapOfferItem(item, offer) {
return {
itemname: item.market_name,
market_hash_name: item.market_hash_name,
steamid: args.offer.steamid_other,
tradeofferid : args.offer.tradeofferid
};
}
function loadPartnerInventory(args) {
var deferred = Q.defer();
offers.loadPartnerInventory(args, function(err, items) {
var checkedItems = items.filter(function(item) => {
return args.itemIds.indexOf(item.id) >= 0;
}).map(function(item) {
return mapOfferItem(item, args.offer);
});
deferred.resolve(checkedItems);
});
return deferred.promise;
}
function loadMyInventory(args) {
var deferred = Q.defer();
offers.loadMyInventory(args, function(err, items) {
var checkItems = items.filter(function(item) {
return args.itemIds_g.indexOf(item.id);
}).map(function(item) {
return mapOfferItem(item, args.offer);
});
deferred.resolve(checkItems);
});
return deferred.promise;
}
function getPartnerInventory(offers, offer, itemIds, itemIds_g) {
var p1 = loadPartnerInventory({
partnerSteamId: offer.steamid_other,
appId: 730,
contextId: 2
});
var p2 = loadMyInventory({appId: 730, contextId: 2});
return Q.all([p1, p2]).spread(function(checkItems, checkItems_g) {
return {
checkItems: checkItems,
checkItems2: checkItems_g
};
});
}
You can then use the function like this:
getParentInventory(offers, offer, itemIds, itemIds_g)
.then(function(checkItems) {
console.log(checkItems);
// should print {checkItems: [...], checkItems2: [...]}
});