Clean up HLS stream

Without this, it will continue loading chunks in the background.

layers/dot-cams/index.js

@@ -62,6 +62,7 @@ for (let [state, url] of Object.entries(allStates)) {
                 var hls = new Hls();
                 hls.loadSource(view.src);
                 hls.attachMedia(video);
+                vectorLayer.destroyPopupCallback = () => hls.destroy();
             }
             // iDevice support, untested (only works in Safari; required for iPhones)
             else if (video.canPlayType('application/vnd.apple.mpegurl')) {

main.js

@@ -23,12 +23,6 @@ const popupOverlay = new Overlay({
   },
 });
 
-closer.onclick = function () {
-  popupOverlay.setPosition(undefined);
-  closer.blur();
-  return false;
-};
-
 const contextMenu = new ContextMenu({
   width: 170,
   defaultItems: false,
@@ -147,6 +141,15 @@ map.on('click', function (evt) {
   }
 
   popupOverlay.setPosition(evt.coordinate);
+
+  closer.onclick = function (){
+    popupOverlay.setPosition(undefined);
+    if (layer.hasOwnProperty('destroyPopupCallback')) {
+      layer.destroyPopupCallback(feature);
+    }
+    closer.blur();
+    return false;
+  };
 });
 
 new ResizeObserver(() => map.updateSize()).observe(document.getElementById("map"));