layerView.queryExtent returns null if features are not in current map extent

Strahanjen

I'm using the follow snippet of code to zoom to the extent of graphics in a featurelayer. It works great when the map starts at the full extent. If I remove some graphics and add new graphics that are in an area that is not currently visible on the map, the queryExtent returns a null extent. However, if I add code to zoom to the full extent of the map first, then the queryExtent returns the extent. Anyone know how I can get this to work without zooming home each time I want to zoom to the extent of the layer? 

    function zoomToLayer(layer) {

        /*first zoom to home to get around queryExtent bug. 

         Getting the queryExtent for a  layerview does not work if the 

         extent of the features is not visible in the map */

        /*

        view.goTo({

            center: [-94.25,45.98],

            zoom: 7

        });*/

          

        view.whenLayerView(layer).then((layerView) => {

            var handle = layerView.watch("updating", function(val) {

                // wait for the layer view to finish updating

                if (!val) {

                  layerView.queryExtent().then(function(response) {

                      console.log(response);

                    //remove the layer updating watch handler

                    handle.remove();

                    // go to the extent of all the graphics in the layer view

                    view.goTo(response.extent);

                  });

                }

              });

        });

    }

Jeff-Reinhart

Would like to clarify on this topic a little further. If I am interpreting the original post right, the intended approach is:

• Load all features for a FeatureLayer to the map.
• Add a definitionExpression to the FeatureLayer to filter the layer.
• Set the map extent to the extent of the filtered FeatureLayer.
• Change the definitionExpression on the FeatureLayer to filter to another feature or feature set in an area not currently in the view.
• Set the map extent to that of the updated filtered FeatureLayer.

The goal is to do this without having to query the service to get the extent of the filtered FeatureLayer. Considering the FeatureLayer is already loaded to the client, another query to the service should not be necessary. I have been experimenting with the same approach.

The docs for FeatureLayer.queryExtent() state “To query for the extent of features/graphics available to or visible in the View on the client rather than making a server-side query, you must use the FeatureLayerView.queryExtent() method.”

This would indicate that the approach above is not possible without zooming back out to the full FeatureLayer extent prior to setting the map extent the second time. Running FeatureLayer.queryExtent() will result in another query to the service. Running FeatureLayerView.queryExtent() will not query the service but it will not correctly set the map extent unless the next feature set is in the view when FeatureLayerView.queryExtent() is executed.

I did some testing, and what I am seeing indicates that running FeatureLayer.queryExtent() DOES query the service. Running FeatureLayerView.queryExtent() does not query the service.

Am I missing something?