Node.JS read directory

_NodeJS_read_directory.md

read directory - opendir vs readdir

create 1000 txt file.
calc 10 times runtime.

createSampleFile_toTestReadDir.js

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

let allPromises = [];

const data = new Uint8Array(Buffer.from('Hello Node.js'));

for(let i=1; i<=1000; i++) {
    let fileName = `sample${i}.txt`;
    let filePath = path.join('../testDir/readfilelist_test/', fileName);
    let f = fsPromises.writeFile(filePath, data);
    allPromises.push(f);
}

Promise.all(allPromises);
// create file sample1.txt ~ sample1000.txt to '../testDir/readfilelist_test/'

createSampleFile_toTestReadDir.result.txt

...
sample261.txt               sample442.txt               sample623.txt               sample804.txt               sample986.txt
sample262.txt               sample443.txt               sample624.txt               sample805.txt               sample987.txt
sample263.txt               sample444.txt               sample625.txt               sample806.txt               sample988.txt
sample264.txt               sample445.txt               sample626.txt               sample807.txt               sample989.txt
sample265.txt               sample446.txt               sample627.txt               sample808.txt               sample99.txt
sample266.txt               sample447.txt               sample628.txt               sample809.txt               sample990.txt
sample267.txt               sample448.txt               sample629.txt               sample81.txt                sample991.txt
sample268.txt               sample449.txt               sample63.txt                sample810.txt               sample992.txt
sample269.txt               sample45.txt                sample630.txt               sample811.txt               sample993.txt
sample27.txt                sample450.txt               sample631.txt               sample812.txt               sample994.txt
sample270.txt               sample451.txt               sample632.txt               sample813.txt               sample995.txt
sample271.txt               sample452.txt               sample633.txt               sample814.txt               sample996.txt
sample272.txt               sample453.txt               sample634.txt               sample815.txt               sample997.txt
sample273.txt               sample454.txt               sample635.txt               sample816.txt               sample998.txt
sample274.txt               sample455.txt               sample636.txt               sample817.txt               sample999.txt
sample275.txt               sample456.txt               sample637.txt               sample818.txt
sample276.txt               sample457.txt               sample638.txt               sample819.txt
sample277.txt               sample458.txt               sample639.txt               sample82.txt
sample278.txt               sample459.txt               sample64.txt                sample820.txt

opendir.js

const fs = require('fs');
const fsPromises = fs.promises;

async function opendir(path) {
    let dir = await fsPromises.opendir(path);
    for await (const dirent of dir) {
        // console.log(dirent);
    }
}

// 10 times test
async function test() {
    for(let i=0; i<10; i++) {
        console.time('opendir');
        await opendir('../testDir/readfilelist_test/');
        console.timeEnd('opendir');
    }
}

test();

opendir.result.txt

opendir: 7.571ms
opendir: 3.567ms
opendir: 6.059ms
opendir: 5.12ms
opendir: 2.688ms
opendir: 2.341ms
opendir: 4.05ms
opendir: 1.899ms
opendir: 2.151ms
opendir: 1.863ms

readdir.js

const fs = require('fs');
const fsPromises = fs.promises;

async function readdir(path) {
    let dirents = await fsPromises.readdir(path, {withFileTypes:true})
    for(const dirent of dirents) {
        // console.log(dirent);
    }
}

async function test() {
    for(let i=0; i<10; i++) {
        console.time('readdir');
        await readdir('../testDir/readfilelist_test/');
        console.timeEnd('readdir');
    }
}

test();

readdir.result.txt

readdir: 2.6ms
readdir: 2.079ms
readdir: 1.24ms
readdir: 1.123ms
readdir: 1.094ms
readdir: 1.198ms
readdir: 1.138ms
readdir: 1.134ms
readdir: 3.417ms
readdir: 1.134ms