var mongo = require('mongodb').MongoClient;

var url = 'mongodb://localhost:27017/test';

var update = function(collection, callback) {
  collection.update({ call:'kf6gpe-7' }, 
    { $set: { lat: 39.0, lng: -121.0, another: true } }, 
    function(error, result) {
      console.log('Updated with error ' + error);
      console.log(result);
      callback(result);
    });
};

mongo.connect(url, function(error, db) {
  console.log("mongo.connect returned " + error);

  // Get the documents collection
  var collection = db.collection('documents');
  update(collection, function(result) {
    db.close();
  });
});