chore: refactor solution

Author: yuwu9145

packages/vuetify/src/composables/nested/nested.ts

@@ -27,7 +27,7 @@ import {
   leafSelectStrategy,
   leafSingleSelectStrategy,
 } from './selectStrategies'
-import { consoleError, getCurrentInstance, getUid, propsFactory } from '@/util'
+import { arrayDiff, consoleError, getCurrentInstance, getUid, propsFactory } from '@/util'
 
 // Types
 import type { InjectionKey, PropType, Ref } from 'vue'
@@ -303,13 +303,13 @@ export const useNested = (props: NestedProps) => {
         const newActivated = activeStrategy.value.activate({
           id,
           value,
-          activated: activated.value,
+          activated: new Set(activated.value),
           children: children.value,
           parents: parents.value,
           event,
         })
 
-        newActivated && newActivated.size && activated.value !== newActivated && (activated.value = newActivated)
+        newActivated && arrayDiff(activated.value, newActivated).length && (activated.value = newActivated)
       },
       children,
       parents,

packages/vuetify/src/util/helpers.ts

@@ -378,11 +378,14 @@ export function filterInputAttrs (attrs: Record<string, unknown>) {
 
 /**
  * Returns the set difference of B and A, i.e. the set of elements in B but not in A
+ * A and B can be sets, but the function always returns the result as an array.
  */
-export function arrayDiff (a: any[], b: any[]): any[] {
+export function arrayDiff (a: any[] | Set<any>, b: any[] | Set<any>): any[] {
   const diff: any[] = []
-  for (let i = 0; i < b.length; i++) {
-    if (!a.includes(b[i])) diff.push(b[i])
+  const aArr: any[] = a instanceof Set ? Array.from(a) : a
+  const bArr: any[] = b instanceof Set ? Array.from(b) : b
+  for (let i = 0; i < bArr.length; i++) {
+    if (!aArr.includes(bArr[i])) diff.push(bArr[i])
   }
   return diff
 }