Merge pull request #11882 from simonseyock/vector-source-load-events-doc

Improved documentation for feature load events.

examples/vector-esri.js

@@ -56,7 +56,7 @@ const styleCache = {
 };
 
 const vectorSource = new VectorSource({
-  loader: function (extent, resolution, projection) {
+  loader: function (extent, resolution, projection, success, failure) {
     const url =
       serviceUrl +
       layer +
@@ -83,6 +83,7 @@ const vectorSource = new VectorSource({
           alert(
             response.error.message + '\n' + response.error.details.join('\n')
           );
+          failure();
         } else {
           // dataProjection will be read from document
           const features = esrijsonFormat.readFeatures(response, {
@@ -91,8 +92,10 @@ const vectorSource = new VectorSource({
           if (features.length > 0) {
             vectorSource.addFeatures(features);
           }
+          success(features);
         }
       },
+      error: failure,
     });
   },
   strategy: tileStrategy(

examples/vector-osm.js

@@ -74,7 +74,7 @@ const styles = {
 
 const vectorSource = new VectorSource({
   format: new OSMXML(),
-  loader: function (extent, resolution, projection) {
+  loader: function (extent, resolution, projection, success, failure) {
     const epsg4326Extent = transformExtent(extent, projection, 'EPSG:4326');
     const client = new XMLHttpRequest();
     client.open('POST', 'https://overpass-api.de/api/interpreter');
@@ -83,7 +83,9 @@ const vectorSource = new VectorSource({
         featureProjection: map.getView().getProjection(),
       });
       vectorSource.addFeatures(features);
+      success(features);
     });
+    client.addEventListener('error', failure);
     const query =
       '(node(' +
       epsg4326Extent[1] +