fix(playground) app shouldn’t crash while user is typing (#9316)

* Update configuration.js

examples/playground/src/configuration.js

@@ -4,7 +4,7 @@
 
 // This configuration object determines which deck.gl classes are accessible in Playground
 
-import {MapView, FirstPersonView, OrbitView, OrthographicView} from '@deck.gl/core';
+import {MapView, FirstPersonView, OrbitView, OrthographicView, View, Layer} from '@deck.gl/core';
 import * as Layers from '@deck.gl/layers';
 import * as AggregationLayers from '@deck.gl/aggregation-layers';
 import * as GeoLayers from '@deck.gl/geo-layers';
@@ -57,5 +57,19 @@ export default {
   constants: {
     Tiles3DLoader,
     CesiumIonLoader
+  },
+
+  postProcessConvertedJson: json => {
+    // Filter out invalid props. Typically, props will be invalid while the user is typing.
+    if (json.layers) {
+      json.layers = json.layers.filter(layer => layer instanceof Layer);
+    }
+    if (json.widgets) {
+      json.widgets = json.widgets.filter(widget => typeof widget.onAdd === 'function');
+    }
+    if (json.views && !(json.views instanceof View)) {
+      json.views = json.views.filter(view => view instanceof View);
+    }
+    return json;
   }
 };