RangeError maximum call stack size exceeded - node.js

Question

For a school project i'm working a nodejs application.
I need to submit some locations of random pokemon. At this moment i'm using dummy data but i'm already getting errors.
I submit to a maximum of 10 locations to mongodb using mongoose but get the following error:
RangeError: Maximum call stack size exceeded
The data is valid to the mongoose Schema. The error is shown also when i submit just 1 location (as it own, not included in a array).
{ _id: 5702bcc7698a36c82833a943,
name: 'Pikachu',
pid: 0,
lng: 5.298302246195419,
lat: 51.68774273818562 }.
My code looks like this:
var startDate = new Date();
if (!req.query.lat || !req.query.lng){
res.status(400).json("Your location has not been included");
}
var lat = parseFloat(req.query.lat);
var lng = parseFloat(req.query.lng);
location.find({}).exec(function(err, locations){
if (err){ return next(err); }
var filteredlocations = [];
locations.forEach(function(fetchedLocation) {
distance = calcDistance(fetchedLocation.lat, fetchedLocation.lng, lat, lng);
if (distance < 1000){
filteredlocations.push(fetchedLocation);
}
});
if (filteredlocations.length < 10) {
var toAdd = 1 - filteredlocations.length;
var newlocations = [];
for (var i = 0; i < toAdd; i++){
var randomlocation = randomLocation(lat, lng);
var newlocation = new location({
"lat": randomlocation.lat,
"lng": randomlocation.lng,
"pid": 0,
"name": "Pikachu",
});
newlocations.push(newlocation);
}
console.log(newlocations[0]);
location.collection.insert(newlocations[0], onInsert);
function onInsert(err, docs){
if (err){
console.log("err: " + err);
} else {
filteredlocations.push(docs);
res.json(filteredlocations);
}
}
}
});