feat: safe.append and safe.remove

packages/preload/loading.ts

@@ -43,12 +43,25 @@ export function useLoading() {
 
   return {
     appendLoading() {
-      document.head.appendChild(oStyle)
-      document.body.appendChild(oDiv)
+      safe.append(document.head, oStyle)
+      safe.append(document.body, oDiv)
     },
     removeLoading() {
-      document.head.removeChild(oStyle)
-      document.body.removeChild(oDiv)
+      safe.remove(document.head, oStyle)
+      safe.remove(document.body, oDiv)
     },
   }
 }
+
+const safe = {
+  append(parent: HTMLElement, child: HTMLElement) {
+    if (!Array.from(parent.children).find(e => e === child)) {
+      return parent.appendChild(child)
+    }
+  },
+  remove(parent: HTMLElement, child: HTMLElement) {
+    if (Array.from(parent.children).find(e => e === child)) {
+      return parent.removeChild(child)
+    }
+  },
+}