Merge pull request #627 from openlayers/fix_missing_source_issue

Fix missing source issue

CHANGES.md

@@ -8,6 +8,7 @@
   * Port to OpenLayers 5.1.3.
   * Switch to Cesium Ion (old terrain service is deprecated and will be stopped in September).
   * Add an old fashioned example (currently requires a custom build of OpenLayers).
+  * Fix synchronization issue when a layer has no initial source.
 
 # v 2.1 - 2018-07-13
 

examples/vectors.js

@@ -274,9 +274,9 @@ const cartographicRectangle2 = new olFeature({
 cartographicRectangle2.setStyle(cartographicRectangleStyle);
 
 const vectorLayer = new olLayerVector({
-  source: vectorSource,
   style: styleFunction
 });
+setTimeout(() => vectorLayer.setSource(vectorSource), 2000);
 
 const vectorSource2 = new olSourceVector({
   features: [iconFeature, textFeature, cervinFeature, ...modelFeatures, cartographicRectangle,

src/olcs/VectorSynchronizer.js

@@ -111,6 +111,10 @@ class VectorSynchronizer extends olcsAbstractSynchronizer {
       source = source.getSource();
     }
 
+    if (!source) {
+      return null;
+    }
+
     googAsserts.assertInstanceof(source, olSourceVector);
     googAsserts.assert(this.view);