CODEWITHSUNDEEP
javascriptnode.jsmongodbasynchronous
Nick Prozee
Nick Prozee

Reputation: 2913

NodeJs + Mongo db unable to wait result

I'm using NodeJs and MongoDB to dev a Web Api.
I encounter the problem that my await statements are not being awaited...

Here is a code example and the output, it makes no sense to me..

Code

   async find_nearby_places(lng, lat, tag, maxDistance) {
    let results = [];

    await MongoClient.connect(url, async function (err, db) {
        let places= db.db(db_name).collection(collection_places);

        let nearbyplaces = places.find({
            "location":
                {
                    $near:
                        {
                            $geometry: {
                                coordinates: [lng, lat]
                            },
                            $maxDistance: maxDistance
                        }
                },
            "tags": {
                $in: [tag]
            }
        });

        await nearbyplaces.toArray().then(
            async placeArray => {
                placeArray.forEach(place => {
                    console.log("API: FOUND place");
                    results.push(placeModel.ToplaceModel(place))
                });
                await db.close();
            });
        console.log(' ---------------------- DONE')
    });
    console.log(" ---------------------- EXIT");
}

Output

 ---------------------- EXIT 
API: FOUND place 
API: FOUND place 
---------------------- DONE

Expected output

API: FOUND place
API: FOUND place
 ---------------------- DONE
 ---------------------- EXIT

Upvotes: 2

Views: 309

Answers (2)

Dathan
Dathan

Reputation: 4553

Await only waits if a promise is returned, for functions with callbacks, new promise has to be defined.

async find_nearby_places() {

  await new Promise((resolve, reject) => {
    MongoClient.connect(url, async function (err, db) {
       //Do tasks
       Promise.resolve()
    }
  })
}

The resolution can be done with any value, in which case the promise will give back that returned value.

Upvotes: 1

Janen R
Janen R

Reputation: 749

Your function find_nearby_places is an async function . . then your other actions except console.log(" ---------------------- EXIT"); are on await mode..

Soo this line console.log(" ---------------------- EXIT"); never wait for to execute. but other actions are in await mode.so they are to be executed one by one as long as to be waited

Upvotes: 0

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