fixed YMap

src/utils/isParentOf.js

@@ -3,24 +3,23 @@
  */
 
 import { Y } from '../utils/Y.js' // eslint-disable-line
-import { Type } from '../types/AbstractType.js/index.js.js.js.js' // eslint-disable-line
+import { AbstractType } from '../types/AbstractType.js' // eslint-disable-line
 
 /**
  * Check if `parent` is a parent of `child`.
  *
- * @param {Type | Y} parent
- * @param {Type | Y} child
+ * @param {AbstractType} parent
+ * @param {AbstractType} child
  * @return {Boolean} Whether `parent` is a parent of `child`.
  *
  * @public
  */
 export const isParentOf = (parent, child) => {
-  child = child._parent
-  while (child !== null) {
+  while (child._item !== null) {
     if (child === parent) {
       return true
     }
-    child = child._parent
+    child = child._item.parent
   }
   return false
 }