suggestion on using mocked on functions with multiple signatures

[eleith]

i'm looking for suggestions on using the mocked helper with functions which have multiple signatures

as an example, readdir from node's fs/promises module supports multiple signatures that are discriminated by options.withFileTypes

if withFileTypes is true, the return type of calls to readdir is Promise<Dirent[]> otherwise the return type is Promise<string[]>

import { readdir } from 'fs/promises'

vi.mock('fs')

const mockReaddir = vi.mocked(readdir)

// the below will throw a typescript error
mockReaddir.mockReaddir.mockResolvedValueOnce(['a', 'b']) 

// the below will NOT throw a typescript error
mockReaddir.mockReaddir.mockResolvedValueOnce(['a', 'b'] as unknown as Dirent[]) 

currently, vi.mocked narrows down to the Dirent version by default. thus, here is the current workaround i'm using

import { readdir } from 'fs/promises'

vi.mock('fs')

const mockReaddirDirent = vi.mocked(readdir)
const mockReaddirString = vi.mocked(readdir as (path: string) => Promise<string[]>)

mockReaddir.mockReaddirString.mockResolvedValueOnce(['a', 'b']) 

mockReaddir.mockReaddirDirent.mockResolvedValueOnce(['a', 'b'] as unknown as Dirent[])