Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
eater
Search
Yosuke Furukawa
PRO
April 26, 2016
Programming
2
1.4k
eater
node 学園付属小学校の2回目で話した eater の話です。
Yosuke Furukawa
PRO
April 26, 2016
Tweet
Share
More Decks by Yosuke Furukawa
See All by Yosuke Furukawa
デザインシステムが必須の時代に
yosuke_furukawa
PRO
2
210
Node.js, Deno, Bun 最新動向とその所感について
yosuke_furukawa
PRO
10
5k
Welcome JSConf.jp 2024
yosuke_furukawa
PRO
1
4.6k
tc39 x jsconf.jp Panel Discussion 2024
yosuke_furukawa
PRO
0
310
Removing Corepack
yosuke_furukawa
PRO
9
1.9k
JavaScript Runtime とはなにか
yosuke_furukawa
PRO
15
3k
Strip Types と Storage
yosuke_furukawa
PRO
4
480
Module Harmony について
yosuke_furukawa
PRO
4
1.8k
LTのやり方
yosuke_furukawa
PRO
16
2.9k
Other Decks in Programming
See All in Programming
AI Assistants for Your Angular Solutions
manfredsteyer
PRO
0
150
Feature Toggle は捨てやすく使おう
gennei
0
200
Everything Claude Code OSS詳細 — 5層構造の中身と導入方法
targe
0
150
Java 21/25 Virtual Threads 소개
debop
0
200
PHPのバージョンアップ時にも役立ったAST(2026年版)
matsuo_atsushi
0
210
OTP を自動で入力する裏技
megabitsenmzq
0
120
『Kubernetes ☸️ で実践する Platform Engineering 』を最高速度で読み抜いたる!!👊🏻
hiroki_hasegawa
0
100
米国のサイバーセキュリティタイムラインと見る Goの暗号パッケージの進化
tomtwinkle
2
630
野球解説AI Agentを開発してみた - 2026/02/27 LayerX社内LT会資料
shinyorke
PRO
0
350
Codexに役割を持たせる 他のAIエージェントと組み合わせる実務Tips
o8n
4
1.4k
Redox OS でのネームスペース管理と chroot の実現
isanethen
0
380
エンジニアの「手元の自動化」を加速するn8n 2026.02.27
symy2co
0
170
Featured
See All Featured
So, you think you're a good person
axbom
PRO
2
2k
Primal Persuasion: How to Engage the Brain for Learning That Lasts
tmiket
0
300
Believing is Seeing
oripsolob
1
89
Build The Right Thing And Hit Your Dates
maggiecrowley
39
3.1k
Templates, Plugins, & Blocks: Oh My! Creating the theme that thinks of everything
marktimemedia
31
2.7k
We Are The Robots
honzajavorek
0
200
SEO in 2025: How to Prepare for the Future of Search
ipullrank
3
3.4k
The Director’s Chair: Orchestrating AI for Truly Effective Learning
tmiket
1
130
Designing Dashboards & Data Visualisations in Web Apps
destraynor
231
54k
Designing for Performance
lara
611
70k
Side Projects
sachag
455
43k
The agentic SEO stack - context over prompts
schlessera
0
700
Transcript
Eater @yosuke_furukawa
@yosuke_furukawa
Hello, Noders. This is Full-time Papa committer
None
child_process.spawn()
None
Node Quiz
Quiz: child_process API ͷԼهͷ ҧ͍ԿͰ͠ΐ͏ 1. exec 2. spawn 3.
fork
A: spawn ͕Ұ൪ϩʔϨϕϧ exec/fork spawn ͷ wrapper
A: exec callback Ͱड͚Δɺ fork JavaScript ͷίʔυ Λ
Node.js ͱͯ͠࠶࣮ߦ͢Δ
child_process.spawn const spawn = require('child_process').spawn; const ls = spawn('ls', [‘-al']);
ls.stdout.on('data', (data) => { console.log(data); }); ls.stderr.on('data', (data) => { console.log(data); }); ls.on('exit', (code) => { if (code !== 0) console.error(`Error occurred`); });
child_process.exec const exec = require('child_process').exec; exec(‘ls -al‘, (err, stdout, stderr)
=> { console.log(`${stdout}`); console.error(`${stderr}`); if (error !== null) { console.error(`Error occurred`); } });
child_process.fork const fork = require('child_process').fork; const ls = fork(‘ls.js’); ls.stdout.on('data',
(data) => { console.log(data); }); ls.stderr.on('data', (data) => { console.log(data); }); ls.on('exit', (code) => { if (code !== 0) console.error(`Error occurred`); });
spawn > exec ͜ͷॱͰ simple exec > spawn ͜ͷॱͰ easy
spawn > fork ͜ͷॱͰ simple fork > spawn ͜ͷॱͰ easy
Easy / Simple ͷҧ͍
None
Simple !== Easy
Simple is “୯७” ٬؍తɺҰͭͷࣄ͔͠͠ͳ͍
Easy is “؆୯” ओ؍తɺ”୭͔”ʹͱͬͯ؆୯ “୭ʹͱͬͯ؆୯” ଘࡏ͠ͳ͍
ॳ৺ऀ͕ؕΓ͕ͪͳࣄɿ Easy ͷݴ༿ʹὃ͞Ε͕ͪ ୭ʹͱͬͯEasy ͳΜͯ͋Γ ͑ͳ͍
ॳ৺ऀ͕ؕΓ͕ͪͳࣄɿ Simple ͱ Easy Λࠞಉ͍ͯ͠ Δʹࠔ͞Ε͕ͪ
Eater
Eater is *Ea*sy *t*est runn*er*
Eater has one simple rule If test file outputs `stderr`
message, the test failed.
Easy => ୭ʹͱͬͯʁ `node` ͔͠Βͳ͍Α͏ͳਓ mocha/jestͷࡉ͔͍ߏจΛ֮ ͑ͯͳͯ͘ɺnode ίϚϯυ ͰεΫϦϓτͱ࣮ͯ͠ߦ͢Δ ͚ͩͰΠφϑͳਓ
Eaterͷtest script `node` command Ͱ࣮ߦͰ͖Δ
Easy => ୭ʹͱͬͯʁ mock/spyΛଟ༻͢Δ͚Ͳɺ mock/spyͷ։์࿙ΕΛΕ ͕ͪͳਓʹͱͬͯ
EaterͷtestҰͭҰ͕ͭผϓ ϩηεͰ࣮ߦ͞ΕΔ
mockΛ։์͠ͳͯ͘OK // you don’t need to fix mock/spy console.log =>
(message) { assert(message.match(/Foo Bar/)); }; const mockDate = new Date(2016, 3, 9); Date.now = () => { return mockDate.valueOf(); }; process.exit => (exitcode) { assert(exitcode === 1); };
͔͠ϓϩηείΞͰ ಄ଧͪʹͳΔ eater ——procs 4 ※procs optionͰՄม
Eater DEMO https://github.com/yosuke- furukawa/eater-demo
Happy Eater https://github.com/yosuke- furukawa/eater