chore: update

Author: edison1105

packages/runtime-dom/src/apiCustomElement.ts

@@ -627,13 +627,16 @@ export class VueElement
    * Only called when shadowRoot is false
    */
   private _parseSlots(remove: boolean = true) {
+    if (!this._slotNames) this._slotNames = new Set()
+    else this._slotNames.clear()
+
     const slots: VueElement['_slots'] = (this._slots = {})
     let n = this.firstChild
     while (n) {
       const slotName =
         (n.nodeType === 1 && (n as Element).getAttribute('slot')) || 'default'
       ;(slots[slotName] || (slots[slotName] = [])).push(n)
-      ;(this._slotNames || (this._slotNames = new Set())).add(slotName)
+      this._slotNames.add(slotName)
       const next = n.nextSibling
       if (remove) this.removeChild(n)
       n = next
@@ -728,10 +731,10 @@ export class VueElement
 
     // switch between fallback and provided content
     if (this._slotFallbacks) {
-      const oldSlotNames = Object.keys(this._slots!)
+      const oldSlotNames = Array.from(this._slotNames!)
       // re-parse slots
       this._parseSlots(false)
-      const newSlotNames = Object.keys(this._slots!)
+      const newSlotNames = Array.from(this._slotNames!)
       const allSlotNames = new Set([...oldSlotNames, ...newSlotNames])
       allSlotNames.forEach(name => {
         const fallbackNodes = this._slotFallbacks![name]