Assertion Error:1 ==0 for MongoDB deleteOne Command

Native mongodb biblioteket har brug for _id at være ObjectId

Slutresultatet ville se mere-mindre ud som dette:

var mongo = require('mongodb');

// Other code lines

router.delete('/formula-list/:id', function(req, res){
  var db = req.db.collection('formulas');
  var query = { "_id": new mongo.ObjectId(req.params.id) };
  db.deleteOne(query, function(err, r){
    assert.equal(null, err);
    assert.equal(1, r.deletedCount);
    db.close();
  });
  res.end();
});