async-iterator.js

'use strict'

const fs = require('fs').promises
const path = require('path')

async function* getPaths(p, depth = 0) {
  const dir = await fs.opendir(p, {
    bufferSize: 1
  })

  for await (const entry of dir) {
    if (!entry.isDirectory()) continue

    yield entry
    if (depth < 2) {
      const fp = path.join(p, entry.name)
      yield* getPaths(fp, depth + 1)
    }
  }
}

;(async () => {
  for await (const thing of getPaths('/usr/sbin')) {
    console.log(thing)
  }
})()
  .then(() => console.log('done'))
  .catch((err) => {
    console.error(err)
  })

The output of that for me is this:

Dirent { name: 'iRATBW.mlmodelc', [Symbol(type)]: 2 }
Dirent { name: 'model0', [Symbol(type)]: 2 }
Dirent { name: 'model1', [Symbol(type)]: 2 }
Dirent { name: 'authserver', [Symbol(type)]: 2 }
[Error: EACCES: permission denied, opendir '/usr/sbin/authserver'] {
  errno: -13,
  code: 'EACCES',
  syscall: 'opendir',
  path: '/usr/sbin/authserver'
}