Uncaught TypeError: Cannot read properties of null (reading '0')

siefaqel

I am trying to query features from the feature layer view and add these features to a graphics layer to enable snapping on the features using the sketch view model I already have, but on a large scale, i start to see this error: " Uncaught TypeError: Cannot read properties of null (reading '0') ".

 

NOTE: when I comment : " gfxLayer.add(g) " or  " new FeatureSnappingLayerSource({ layer: gfxLayer as __esri.GraphicsLayer, 

enabled: true,

             }), "  or " visible: false," I don't see the error anymore, but snapping does not work.

any thoughts?

 

 

 

sketchVmRef.current = new SketchViewModel({
        view: mapView,
        layer: new GraphicsLayer({}),
        snappingOptions: {
          enabled: true,
          featureSources: [
             new FeatureSnappingLayerSource({
               layer: gfxLayer as __esri.GraphicsLayer,
               enabled: true,
             }),
          ],
        },
      })
    
const queriedFeatures = await featureLayerView.queryFeatures({
          where: `1=1`,
          outFields: ['*'],
          returnGeometry: true,
        })
       
        for (const feature of queriedFeatures.features) {
          
            const g = new Graphic({
              geometry: feature.geometry,
              attributes: feature.attributes,
              layer: gfxLayer,
              // visible: false,
            })
            gfxLayer.add(g)

        }

 

JoelBennett

The error appears to be driven by your implementation of "gfxLayer".  Can you provide more code as it relates to that object (i.e. its construction, setting of properties, etc)?

I encountered this same error message yesterday, although it's unlikely we had the same problem.  The error message occurs when an Array is expected, but a value of null is received.  In my case, I was trying to use a UniqueValueRenderer created from JSON with the uniqueValueGroups specified.  The JSON structure for uniqueValueGroups differs from the autocast structure, and is still undocumented, but I fumbled my way through it.