Firebase Queue - Handling Reject/Resolve while Looping - firebase

Question

I have a Queue that looks like this
new Queue(queueRef, options, ({post, user, postId}, progress, resolve, reject) => {
rootRef.child(`users/${user.user_id}/followers`).once('value', (snapshot) => {
const followers = toArray(snapshot.val())
for (var i = 0; i < followers.length; i++) {
rootRef.child(`users/${followers[i].user_id}/feed/${postId}`).set(post, (err) => {
if (err) {
reject(err)
} else if (i >= followers.length - 1) {
resolve({post, user, postId})
}
})
}
}, reject)
})
My issue is that I'm really only resolving once all the sets have finished and rejecting if any of those fail. What I'd like to do is somehow pass each iteration of a loop to another Queue which can then reject/resolve for that specific request rather than the whole collection.

Answer 1

This looks like it's probably an XY problem and probably has a better solution. But you're looking for something like Q.all().
In essence, call a method that does each op and returns a promise, and resolve/reject when the entire set is done.
new Queue(queueRef, options, ({post, user, postId}, progress, resolve, reject) => {
rootRef.child(`users/${user.user_id}/followers`).once('value', (snapshot) => {
var promiseList = [], p;
const followers = toArray(snapshot.val())
for (var i = 0; i < followers.length; i++) {
p = processNextFollower(followers[i]);
// p.then(progress);
promiseList.push(p);
}
Q.all(promiseList).then(resolve, reject);
}, reject)
})
function processNextFollower(follower, postId) {
var def = Q.defer();
rootRef.child(`users/${follower.user_id}/feed/${postId}`).set(post, (err) => {
if (err) {
def.reject(err)
} else if (i >= followers.length - 1) {
def.resolve({post, user, postId})
}
})
}
return def.promise;
}