Mongoose find the first nearest location

Question

In my MongoDB database I have tons of location (coordinates can be duplicated) . I'm trying to get the first nearest location (longitude / latitude). Inside my model I have this :

var mySchema = new Schema({
    loc:{
        type : [Number],
        index: '2d'
    },
    ...
});

I see than MongoDB implement $near method to calculate the nearest locations. Then I tried this

Model.find({loc: {$near:[1.4072964, 7.826107], $maxDistance: 1} }, function(err, result){
    result.forEach(function(doc){
        console.log(doc.loc)
    })
}); 

The problem is that it will returns all locations nearest to this point around 1 meter. But I don't need max distance I just want the first nearest location found.

I can't use findOne for this because I need to get all duplicated data for this first location.

Eg If the first coordinate found is -5.95001220703125, 51.5499954223633 and I have this location 10 times, I need to get all documents with this locations.

So it's possible to do this with just once Mongoose Query ? Or I shouldn't use the MongoDB Geospatial Indexing and calculate the nearest distance myself in my application ?

Answer 1

I suggest divide your query in two parts:

• Find the closest document.
• Find duplicates of it.

To find the closest document you can use the $nearsphere operator.

// you can use callbacks if you want
let closestQuery =
  Person
    .find({
      loc: {
        $nearsphere: coords
      }
    })
    .limit(1)
    .exec();

closestQuery.then(doc => ...);

Then you just need to find by the same location in order to fetch duplicates.