Correctly inserting and/or updating many datasets

So from time to time I get new exports of a cities database of POIs and info about them and I want to have all that data in my MongoDB with a Loopback-API on it. Therefore I reduce the data to my desired structure and try to import it.

For the first time I receive such an export, I can simply insert the data with insertMany().

When I get a new export, it means that it includes updated POIs which I actually want my existing POIs to be replaced with that new data. So I thought I'd use updateMany() but I could'nt figure out how I'd do that in my case.

Here's what I have so far:

const fs = require('fs');
const mongoose = require('mongoose');

const data = JSON.parse(fs.readFileSync('data.json', 'utf8'));

// Connect to database
mongoose.connect('mongodb://localhost/test', {
  useMongoClient: true
}, (err) => {
  if (err) console.log('Error', err);
});

// Define schema
let poiSchema = new mongoose.Schema({
  _id:          Number,
  name:         String,
  geo:          String,
  street:       String,
  housenumber:  String,
  phone:        String,
  website:      String,
  email:        String,
  category:     String
});

// Set model
let poi = mongoose.model('poi', poiSchema);

// Generate specified data from given export
let reducedData = data['ogr:FeatureCollection']['gml:featureMember'].reduce((endData, iteratedItem) => {
  endData = endData.length > 0 ? endData : [];

  endData.push({
    _id:          iteratedItem['service']['fieldX'],
    name:         iteratedItem['service']['fieldX'],
    geo:          iteratedItem['service']['fieldX']['fieldY']['fieldZ'],
    street:       iteratedItem['service']['fieldX'],
    housenumber:  iteratedItem['service']['fieldX'],
    phone:        iteratedItem['service']['fieldX'],
    website:      iteratedItem['service']['fieldX'],
    email:        iteratedItem['service']['fieldX'],
    category:     iteratedItem['service']['fieldX']
  });

  return endData;
}, []);

//
// HERE: ?!?!? Insert/update reduced data in MongoDB collection ?!?!?
//

mongoose.disconnect();

So I just want to update everything that has changed.

Of course if I leave it to insertMany() it fails due to dup key.

For the second time, use mongo's update command with upsert set to true.

db.collection.update(query, update, options)

In the query pass the _id ,in update pass the object and in option set upsert to true. This will update the document if it exists creates a new document if that doesn't exist.