Add existing to tracked

node_modules/@cesium/engine/Source/DataSources/getElement.js

@@ -0,0 +1,26 @@
+import DeveloperError from "../Core/DeveloperError.js";
+
+/**
+ * If element is a string, look up the element in the DOM by ID.  Otherwise return element.
+ *
+ * @private
+ *
+ * @exception {DeveloperError} Element with id "id" does not exist in the document.
+ */
+function getElement(element) {
+  if (typeof element === "string") {
+    const foundElement = document.getElementById(element);
+
+    //>>includeStart('debug', pragmas.debug);
+    if (foundElement === null) {
+      throw new DeveloperError(
+        `Element with id "${element}" does not exist in the document.`,
+      );
+    }
+    //>>includeEnd('debug');
+
+    element = foundElement;
+  }
+  return element;
+}
+export default getElement;