Pull entire Latitude history for a user

lat_hist.js

// https://developers.google.com/latitude/v1/using#ListingHistory

var minTimeMs = 0, // Earliest location to pull, 1st Jan 1070 seems far back enough.
    maxTimeMs = Date.new().getTime(), // Latest location to pull, now.
    lastResponse = [];

while {
   // it is assumed this returns a max of 1000 locations in reverse chronological order, 
   // most recent location before maxTime first,
   // then 999 more locations going back in time.
   googleclient.getLocationHistory(minTimeMs, maxTimeMs, function(err, response) {
       if(err) {
           lastResponse = [];
       } else {
           lastResponse = response;
       }
   });

   // this handles duplicates, but it shouldn't get any if the API is behaving 
   storeLocations(lastResponse);

   // terminate when we've got all their history
   if (lastResponse.length == 0) {
       break;
   }
  
   // now we're only interested in locations prior to the 1000 we just got
   maxTime = lastResponse[0].timestampMs;
} 

This will fail miserably because getLocationHistory is asynchronous, but how best should I express it?