How to make for loop in node.js and mongoDB run synchronously

user_9017493 0
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This is my first time with Node.js, and I'm having an issue with it.

I'm getting some data from an API, and I'm storing them on a array.

Then, I'm doing some MongoDB's query to know if the data that I have on that array are in the database.

I thought to use a for loop for every occurrence of array, but when I try to call MongoDB, for loop keep going to increase the counter immediately, without waiting the end of query and relative response, and I get data only for the last occurrence (repeatedly).

There's a part of my code, and with this I get always the 'result' on console relative at the last occurrence (for example, if I expect something like '1, 2, 3, 4, 5', I have '5 5 5 5 5')

How can I do to be sure that for loop works on the right way?

Thanks for help. 

for ( counter = 0; counter < array.lenght; counter ++) {

    MongoClient.connect(url, function (err, db) {

       var query = { name: array[counter] };

       db.collection("collectionName").find(query).toArray(function (err, result) {

           // Check if 'query' value exist in the database, if yes do some stuff, otherwise do others stuff
           console.log(result); 


    }
)

EDIT: Just to let everyone know, the code finally works. Thanks for your help.

node.js mongodb for-loop javascript
2 Answers

Try to run the below code. Let me know if it worked or not.

let fun = async function () {
    for (var counter = 0; counter < array.length; counter++) {
        await MongoClient.connect(url, function (err, db) {
            var query = { name: array[counter] };
            db.collection("collectionName").find(query).toArray(function (err, result) {
                // Check if 'query' value exist in the database, if yes do some stuff, otherwise do others stuff
                console.log(result);
            })
        })
    }
}

fun();
user_79311160
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