Cache busStop dataHEADmaster

The request is still made when you subscribe, but the callback will be called
instantly if the data is cached.

1 files changed, 10 insertions, 0 deletions

diff --git a/uos-live.js b/uos-live.js
index 629fd58..c89c6ae 100644
--- a/uos-live.js
+++ b/uos-live.js
@@ -3,6 +3,7 @@
   window.UoSLive = {};
 
   var busStopRequests = {};
+  var busStopCache = {};
 
   UoSLive.getBusStopURL = function(busStop) {
     var base = "http://bus.southampton.ac.uk/bus-stop/";
@@ -14,6 +15,12 @@
 
   UoSLive.subscribeToBusStop = function(busStop, callback) {
 
+    if (busStop in busStopCache) {
+      var result = busStopCache[busStop];
+      if (result.timeFetched > (Date.now() - 60000)) {
+        callback(result);
+      }
+    }
 
     var url = UoSLive.getBusStopURL(busStop);
 
@@ -24,6 +31,9 @@
     req.recurring = true;
 
     req.on('finished', function(code, result, headers) {
+      result.timeFetched = Date.now();
+      busStopCache[busStop] = result;
+
       callback(result);
     });