useMutation2.tsx

const { data, errors } = await execPostThread({
  variables: {
    threadId: localThread !== null ? localThread.id : "0",
    userId: userProfile ? userProfile!.id : "0",
    title,
    body,
    videoUrl,
    bounty,
    categoryId: selectedCategory!.id
  }
});

if(errors && errors.length) {
  // do something about error
} else {
  // success
}