8261 - Avoid including Cesium3DTileSet in Picking.js

CHANGES.md

@@ -20,6 +20,7 @@ Change Log
 
 ##### Fixes :wrench:
 * Fixed a bug where the camera could go underground during mouse navigation. [#8504](https://github.com/AnalyticalGraphicsInc/cesium/pull/8504)
+* Reduced Cesium bundle size by avoiding unnecessarily importing `Cesium3DTileset` in `Picking.js` [#8532](https://github.com/AnalyticalGraphicsInc/cesium/pull/8532)
 * Fixed WebGL warning message about `EXT_float_blend` being implicitly enabled. [#8534](https://github.com/AnalyticalGraphicsInc/cesium/pull/8534)
 
 ### 1.65.0 - 2020-01-06

Source/Scene/Cesium3DTileset.js

@@ -879,6 +879,18 @@ import TileOrientedBoundingBox from './TileOrientedBoundingBox.js';
     }
 
     defineProperties(Cesium3DTileset.prototype, {
+        /**
+         * NOTE: This getter exists so that `Picking.js` can differentiate between
+         *       PrimitiveCollection and Cesium3DTileset objects without inflating
+         *       the size of the module via `instanceof Cesium3DTileset`
+         * @private
+         */
+        isCesium3DTileset : {
+            get : function() {
+                return true;
+            }
+        },
+
         /**
          * Gets the tileset's asset object property, which contains metadata about the tileset.
          * <p>

Source/Scene/Picking.js

@@ -20,7 +20,6 @@ import  Camera from './Camera.js';
 import  Cesium3DTileFeature from './Cesium3DTileFeature.js';
 import  Cesium3DTilePass from './Cesium3DTilePass.js';
 import  Cesium3DTilePassState from './Cesium3DTilePassState.js';
-import  Cesium3DTileset from './Cesium3DTileset.js';
 import  PickDepth from './PickDepth.js';
 import  PrimitiveCollection from './PrimitiveCollection.js';
 import  SceneMode from './SceneMode.js';
@@ -546,7 +545,7 @@ import  View from './View.js';
         for (var i = 0; i < length; ++i) {
             var primitive = primitives.get(i);
             if (primitive.show) {
-                if ((primitive instanceof Cesium3DTileset)) {
+                if (defined(primitive.isCesium3DTileset)) {
                     if (!defined(objectsToExclude) || objectsToExclude.indexOf(primitive) === -1) {
                         tilesets.push(primitive);
                     }