async/await recursive fs readdir

1.rreaddir.js

import { join } from 'path'
import { readdir, stat } from 'fs-promise'

async function rreaddir (dir, allFiles = []) {
  const files = (await readdir(dir)).map(f => join(dir, f))
  allFiles.push(...files)
  await Promise.all(files.map(async f => (
    (await stat(f)).isDirectory() && rreaddir(f, allFiles)
  )))
  return allFiles
}

2.rreaddirSync.js

// straight synchronous version for perf comparison
import { join } from 'path'
import fs from 'fs'

function rreaddirSync (dir, allFiles = []) {
  const files = fs.readdirSync(dir).map(f => join(dir, f))
  allFiles.push(...files)
  files.forEach(f => {
    fs.statSync(f).isDirectory() && rreaddirSync(f, allFiles)
  })
  return allFiles
}

3.bench.js

import assert from 'assert'

console.time('parallel')
rreaddir(__dirname).then(pFiles => {
  console.timeEnd('parallel')
  console.time('sync')
  const sFiles = rreaddirSync(__dirname)
  console.timeEnd('sync')
  assert.deepEqual(pFiles.sort(alpha), sFiles.sort(alpha))
})

function alpha (a, b) {
  return a.localeCompare(b)
}

4.bench.results.txt

parallel: 313.899ms
sync: 80.259ms

❤️

Seemingly not much difference in performance, which is good:

queue: 935.704ms
sync: 1754.959ms
parallel: 945.062ms

Interesting to see that the parallel version is now much faster than the original sync version. Tested using Node v12.13.0 with slightly adjusted versions of parallel and sync (because my version also leaves out directories in the resulting file list).