How to Ensure Database Queries Finish Before Returning Results in a Loop with MongoDB and Q Promises?

Issue in Returning Retrieved Results from Database Queries Made in a Loop

In this query, the goal is to make multiple MongoDB queries in a loop and send the combined results as a single data array. However, using return within the loop does not wait for the database requests to complete, resulting in an undefined response. Even the use of Q.moulde does not resolve the issue.

Modified Code:

var getPrayerInCat = function(data){
    var promises = data.map(function(data2){
        var id = data2.id;
        return Q.nbind(Prayer.find, Prayer)({prayerCat:id})
            .then(function(prayer) {
                if(!prayer) data2.prayersCount = 0;
                else data2.prayersCount = prayer.length;
                return data2;
            })
    });
    return Q.all(promises);
}

Explanation:

1. Q.nbind: This function converts the Prayer.find method into a function that returns a Q promise.
2. Chain Promises: Each iteration in the loop now returns a promise that resolves with the updated data object.
3. Q.all: This function combines all the promises into a single promise that resolves with an array containing all the updated data objects once all the database queries have completed.
4. return Q.all(promises);: This line ensures the function waits for all the database queries to complete and returns the combined result.

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