Roll back to Array-checking

src/main/resources/lib/turbo-streams/actions.ts

@@ -77,7 +77,7 @@ export function serialize(action: TurboStreamAction): string;
 export function serialize(actions: ReadonlyArray<TurboStreamAction>): string;
 export function serialize(actions: TurboStreamAction | ReadonlyArray<TurboStreamAction>): string;
 export function serialize(actions: TurboStreamAction | ReadonlyArray<TurboStreamAction>): string {
-  return Array.isArray(actions) ? actions.map(serializeOne).join("\n") : serializeOne(actions);
+  return actions instanceof Array ? actions.map(serializeOne).join("\n") : serializeOne(actions);
 }
 
 function serializeOne(action: TurboStreamAction): string {