Node, Q, MongoDB - Upsert an array of objects with a write concern using Q.

promise-upsert-with-a-write-concern

var saveObjects = function (objects) {
    var MongoC = MongoClient;
    var mongoConnect = Q.nbind(MongoC.connect, MongoC);
 
    return mongoConnect(dbString).then(function (db) {
      var DocumentCollection = db.collection('collection');
      var documentCollectionUpsert = Q.nbind(DocumentCollection.update, DocumentCollection);
      //Use upsert option. 
      var options = { 'w' : 1, 'upsert' : true };
      var upsertPromises = objects.map(function (obj) {
          return documentCollectionUpsert(obj, obj, options);
      });
 
      return Q.all(upsertPromises)
      .then(function (results) {
        //check results
        //...
      })
      .finally(function () {
        db.close();
      });
 
    });
  };