var mongo = require('mongodb');

function test(cb) {
	var mongoClient = new mongo.MongoClient();
	mongoClient.connect('mongodb://localhost:27017/test', function (err, db) {
		if (err) {
			return cb(err);
		}
		db.collection('try').updateOne({_id:1}, {$set:{x:1}}, {upsert:true, w: 0}, function(err, result){
			return cb(err, result);
		})
	});
}

test(function(err, result){
	console.log(err);
	console.log(result);
});