Add existing to tracked

node_modules/@cesium/engine/Source/Scene/Cesium3DContentGroup.js

@@ -0,0 +1,44 @@
+import Check from "../Core/Check.js";
+import Frozen from "../Core/Frozen.js";
+
+/**
+ * Simple abstraction for a group. This class exists to make the metadata API
+ * more consistent, i.e. metadata can be accessed via
+ * <code>content.group.metadata</code> much like tile metadata is accessed as
+ * <code>tile.metadata</code>.
+ *
+ * @param {object} options Object with the following properties:
+ * @param {GroupMetadata} options.metadata The metadata associated with this group.
+ *
+ * @alias Cesium3DContentGroup
+ * @constructor
+ * @private
+ * @experimental This feature is using part of the 3D Tiles spec that is not final and is subject to change without Cesium's standard deprecation policy.
+ */
+function Cesium3DContentGroup(options) {
+  options = options ?? Frozen.EMPTY_OBJECT;
+  //>>includeStart('debug', pragmas.debug);
+  Check.typeOf.object("options.metadata", options.metadata);
+  //>>includeEnd('debug');
+
+  this._metadata = options.metadata;
+}
+
+Object.defineProperties(Cesium3DContentGroup.prototype, {
+  /**
+   * Get the metadata for this group
+   *
+   * @memberof Cesium3DContentGroup.prototype
+   *
+   * @type {GroupMetadata}
+   *
+   * @readonly
+   */
+  metadata: {
+    get: function () {
+      return this._metadata;
+    },
+  },
+});
+
+export default Cesium3DContentGroup;