(node:5700) DeprecationWarning: Mongoose: mpromise (mongoose's default promise library) is deprecated, plug in your own promise library instead

Question

I'm getting this warning: DeprecationWarning: Mongoose: mpromise (mongoose's default promise library) is deprecated, plug in your own promise library instead. I got this error when I was trying to do a .find on a model in MongoDb on my backend route. I'm not sure what it means or how to address it.

Below I show the route that is being called that is causing this error. I apologize that i'm not that aware of promises in general, i'm not sure what they mean by "mpromise".

app.get("/search/search=:search&location=:location?", function (req, res) { console.log("I'm in home search back-end")

console.log(req.params.search);
console.log(req.params.location);

var resultObj = {
    search: req.params.search,
    location: {},
    results: []
}

if (req.params.location) {


    var apiKey = "AIzaSyBejz2PGLk2-SG6MI6FCEmyaCQG-7pPuuw"
    var query = "https://maps.googleapis.com/maps/api/place/textsearch/json?query=" + req.params.location + "&key=" + apiKey;
    var query2 = "https://maps.googleapis.com/maps/api/distancematrix/json?units=imperial&origins=" + req.params.location + "&destinations=&key=" + apiKey;
    request(query, function (error, response, body) {
        if (!error && response.statusCode === 200) {
            // console.log(results)

                resultObj.location = JSON.parse(body).results;
                // resultObj.location = body
                var geo = resultObj.location[0].geometry.location
                console.log("I requested google maps api");
                console.log(geo);

            // $near: [geo.lat, geo.lng]



            Item.find({
                // $text: { $search: req.params.search }, 
                'geometry.coordinates': {
                    $geoWithin: {
                        $center: [[geo.lng, geo.lat], 20 / 3963.2 ]
                    }

                }



            })
                .populate('properties.itemReviews')
                // .skip(20)
                .limit(5000)

                .exec(function (err, results) {

                    if (err) {
                        console.log("searching users by location was not successful");
                        console.log(err);
                        res.json({ failedLocation: "This location does not exist" })
                    } else {
                        console.log("ive successfully searched users by location, below is results");
                        console.log(err)
                        console.log(results);
                        resultObj.geoResults = results
                        resultObj.finalResults = [];
                        resultObj.geo = geo;
                        res.json(resultObj)
                    }
                });

            } else {
                res.json({ error: "There was an error with your address" });
            }


    });



} else {
    res.json(resultObj);

}

});

My code is working, I'm just worried about a deprecation causing problems in my code in the future. If there is nothing to worry about, please let me know!

Answer 1

In the server.js file where you have defined mongoose.connect() method. Add above it.

mongoose.Promise = global.Promise; // Use this line.
mongoose.connect('mongodb://url', { useMongoClient: true }, function (err) {
    if (err) {
        console.log('not connected to data base');
    }
    else {
        console.log('Successfully Connected to database');
    }
});