fs access perf test

fs-test.mjs

import fs from 'fs'

let timer = process.hrtime()
for (let i = 0; i < 1000; i++) {
  for (let j = 0; j < 1000; j++) {
    let path = './non/' + i + '/' + j + '.txt'
    // fs.existsSync(path)
    // isFileReadable(path)
    // isFileStat(path)
    // isFileStatFast(path)
    isFileStatFastSafe(path)
  }
}
let delta = process.hrtime(timer)
console.log('took', format(delta))

function isFileReadable(filename) {
  try {
    fs.accessSync(filename, fs.constants.R_OK)
    return true
  } catch {
    return false
  }
}

function isFileStat(filename) {
  try {
    fs.statSync(filename)
    return true
  } catch {
    return false
  }
}

function isFileStatFast(filename) {
  return !!fs.statSync(filename, { throwIfNoEntry: false })
}

const canRead =
  fs.constants.S_IRUSR | fs.constants.S_IRGRP | fs.constants.S_IROTH

function isFileStatFastSafe(filename) {
  const stat = fs.statSync(filename, { throwIfNoEntry: false })
  return stat ? !!(stat.mode & canRead) : false
}

function format(arr) {
  let num = Math.round(arr[1] / 1e6)
  if (arr[0] > 0) return (arr[0] + num / 1e3).toFixed(2) + 's'
  return `${num}ms`
}