feat: render frames on export (#7210)

src/utils.ts

@@ -834,11 +834,18 @@ export const isOnlyExportingSingleFrame = (
   );
 };
 
+/**
+ * supply `null` as message if non-never value is valid, you just need to
+ * typecheck against it
+ */
 export const assertNever = (
   value: never,
-  message: string,
+  message: string | null,
   softAssert?: boolean,
 ): never => {
+  if (!message) {
+    return value;
+  }
   if (softAssert) {
     console.error(message);
     return value;
@@ -931,3 +938,5 @@ export const isMemberOf = <T extends string>(
     ? collection.includes(value as T)
     : collection.hasOwnProperty(value);
 };
+
+export const cloneJSON = <T>(obj: T): T => JSON.parse(JSON.stringify(obj));