From db63cc1b23b729953f603e1bbd29e35e6e629e68 Mon Sep 17 00:00:00 2001
From: cmortazavi <cmortazavi@gmail.com>
Date: Wed, 28 Jun 2017 09:55:37 -0700
Subject: [PATCH] Fix Bug when adding/removing layer with no cache

---
 src/ol/renderer/layer.js | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/ol/renderer/layer.js b/src/ol/renderer/layer.js
index a5745e1377..413e3f25bc 100644
--- a/src/ol/renderer/layer.js
+++ b/src/ol/renderer/layer.js
@@ -152,8 +152,10 @@ ol.renderer.Layer.prototype.scheduleExpireCache = function(frameState, tileSourc
      */
     var postRenderFunction = function(tileSource, map, frameState) {
       var tileSourceKey = ol.getUid(tileSource).toString();
-      tileSource.expireCache(frameState.viewState.projection,
-          frameState.usedTiles[tileSourceKey]);
+      if (tileSourceKey in frameState.usedTiles) {
+        tileSource.expireCache(frameState.viewState.projection,
+            frameState.usedTiles[tileSourceKey]);
+      }
     }.bind(null, tileSource);
 
     frameState.postRenderFunctions.push(