What is the best pattern to conditionally cache function return value with use cache directive and cacheTag?

I have some functions that fetch data from database and have draft argument which when set to true fetches the draft version of the document. This is useful for preview when user is editing something in the admin panel.

I have been thinking about separating my fetch functions into 2 one cached and other not cached, but this leads to too much code duplication.

Do you guys have any ideas?

async function fetchDoc(draft = false) {
  "use cache"

  if (draft) // return live calculated value
  // else return cached value or calculate it if cache miss
}