fix(core): update

ts/index.ts

@@ -10,6 +10,16 @@ export class Smartntml {
     return smartntml;
   }
 
+  private static smartntmlSingletonDeferred: plugins.smartpromise.Deferred<Smartntml>;
+  public static async createAndInitSingleton() {
+    if (this.smartntmlSingletonDeferred) {
+      return this.smartntmlSingletonDeferred.promise;
+    }
+    const smartntmlInstance = await this.createAndInit();
+    this.smartntmlSingletonDeferred.resolve(smartntmlInstance);
+    return this.smartntmlSingletonDeferred.promise;
+  }
+
   // INSTANCE
   render: typeof litTypes.render;
   html: typeof litTypes.html;