Google script postal code resolver

get_postal_code.js

function get_postal_code(street, city, state){
  var cache_seconds = 60 * 60 * 24 * 365 // cache for 1 year
  var address = [street, city, state, "United States"].join(", ")
  var cache = CacheService.getScriptCache();
  var cached = cache.get(address);
  if (cached != null) {
    return cached;
  }

  var randnumber = Math.random()*5000;

  Utilities.sleep(randnumber);
  var response = Maps.newGeocoder().setRegion('com').geocode(address);
  if (response.status === "OK") {
    //Logger.log("response " + JSON.stringify(response));
    try{
      var postal_code = response.results[0].address_components.filter(function(a){ return a.types.indexOf("postal_code") != -1})[0].short_name
      cache.put(address, postal_code, cache_seconds); 
      return postal_code
    }
    catch(e){
      Logger.log(e)
      cache.put(address, "", cache_seconds);
      return ""
    }
  }
  else {
    return "error";
  }
}