call the success callback after the features are added

src/ol/featureloader.js

@@ -156,10 +156,10 @@ export function xhr(url, format) {
        * projection.
        */
       function (features, dataProjection) {
+        source.addFeatures(features);
         if (success !== undefined) {
           success(features);
         }
-        source.addFeatures(features);
       },
       /* FIXME handle error */ failure ? failure : VOID
     );

test/spec/ol/source/vector.test.js

@@ -571,6 +571,24 @@ describe('ol.source.Vector', function () {
       );
     });
 
+    it('fires the FEATURESLOADEND event after the features are added', function (done) {
+      const source = new VectorSource({
+        format: new GeoJSON(),
+        url: 'spec/ol/source/vectorsource/single-feature.json',
+      });
+      source.on('featuresloadend', function () {
+        const features = source.getFeatures();
+        expect(features).to.be.an('array');
+        expect(features.length).to.be(1);
+        done();
+      });
+      source.loadFeatures(
+        [-10000, -10000, 10000, 10000],
+        1,
+        getProjection('EPSG:3857')
+      );
+    });
+
     it('fires the FEATURESLOADEND event if the default load function is used', function (done) {
       const source = new VectorSource({
         format: new GeoJSON(),