fix ts types

Author: danez

packages/react-docgen/src/utils/flowUtilityTypes.ts

@@ -27,9 +27,16 @@ export function isSupportedUtilityType(
  *   $ReadOnly<T> => T
  */
 export function unwrapUtilityType(path: NodePath): NodePath {
-  while (isSupportedUtilityType(path)) {
-    path = path.get('typeParameters').get('params')[0];
+  let resultPath: NodePath = path;
+  while (isSupportedUtilityType(resultPath)) {
+    const typeParameters = resultPath.get('typeParameters');
+    if (!typeParameters.hasNode()) break;
+
+    const firstParam = typeParameters.get('params')[0];
+    if (!firstParam) break;
+
+    resultPath = firstParam;
   }
 
-  return path;
+  return resultPath;
 }