どの非同期処理が良いのか勝負

JSオジサンで発表した資料です。

1. Ͳͷඇಉظॲཧ͕ྑ͍ ͷ͔উෛ @yosuke_furukawa
2. Twitter: @yosuke_furukawa Github: yosuke-furukawa
3. Node.js೔ຊϢʔβʔάϧʔϓ୅ද Node.js Evangelist / Node.js Collaborator
4. ҰԠઆ໌ • Node.js ʹ͸ͨ͘͞Μͷඇಉظॲཧ͕͋Δ • callback • Promise • Stream • generator / yield • (Ͱ͖ͨΒ) async await
5. ͲΕ͕Ұ൪͍͍ͷΑʁ • έʔεόΠέʔε
6. ͲΕ͕Ұ൪͍͍ͷΑʁ • έʔεόΠέʔε ΄Μͱʁʁʁ
7. Callbackࢯ // Ұ൪୯७ɺ஍ࠈΛݟΔ͜ͱ΋͋Δɻ 'use strict'; const fs = require('fs'); fs.readFile('/path/to/foo.txt', (err, foo) => { if (err) { console.error(err); return; } fs.readFile('/path/to/bar.txt', (err, bar) => { if (err) { console.error(err); return; } console.log(`${foo}${bar}`); }); }); Ұ൪୯७͚ͩͲɺ஍ࠈΛݟΔ͜ͱ΋͋Δɻ
8. Promise ࢯ 'use strict'; const fs = require('fs'); const promisify = require('./promisify'); const readFile = promisify(fs.readFile); Promise.all([ readFile('/path/to/foo.txt'), readFile('/path/to/bar.txt'), ]).then((results) => { console.log(results.join('')); }).catch((err) => { console.error(err); }); &4Ͱೖͬͨඪ४ඇಉظॲཧɺਓؾ͋Δ͚Ͳɺ DBODFM͕ͳ͔ͬͨΓͱएׯยखམͪײ͕͋Δɻ
9. Stream ࢯ 'use strict'; const fs = require('fs'); const fooStream = fs.createReadStream('/path/to/foo.txt'); const barStream = fs.createReadStream('/path/to/bar.txt'); fooStream.pipe(process.stdout); barStream.pipe(process.stdout); Node.js ͷதͰ෯Λར͔͍ͤͯΔ࿈ଓͨ͠ σʔλΛѻ͏ͨΊॲཧɺStreamΛ੍͢Δ΋ ͷ͸NodeΛ੍͢Δ
10. generator/yield ࢯ 'use strict'; const co = require('co'); const fs = require('mz/fs'); co(function* (){ const foo = yield fs.readFile('/path/to/foo.txt'); const bar = yield fs.readFile('/path/to/bar.txt'); return foo + bar; }).then((data) => { console.log(data); }); ؔ਺ͷ్தͰࢭΊΔͱ͍͏generatorؔ਺ͷಛੑΛར༻ͨ͠ ॲཧɺ ES2015Ͱ༗ޮʹɻ஗͍ͱ͍͏ᷚ΋͋Δ͕ɺɺɺ
11. async/await ࢯ 'use strict'; const fs = require('mz/fs'); const concat = async function() { const foo = await fs.readFile('/path/to/foo.txt'); const bar = await fs.readFile('/path/to/bar.txt'); return foo + bar; }; console.log(concat()); ESnextͰఏҊதͷ௒৽੕ɻ࢓༷ʹೖΔͷ͸࠶དྷ೥Ҏ͔߱ʁ
12. ͲΕ͕Ұ൪͍͍ͷΑʁ • έʔεόΠέʔε • callback => ୯७ɻͨͩ͠஍ࠈΛݟΔ͕࣌͋Δɻ • Promise => ES2015 Ͱೖͬͨඪ४ඇಉظॲཧɺͳΜͱͳ͘cancel͕ͳ͍ͱ͔ยखམ ͪײ͋Δɻ • Stream => Node.js ͷதͰ෯Λར͔͍ͤͯΔ࿈ଓͨ͠σʔλΛѻ͏ͨΊॲཧɺ StreamΛ੍͢Δ΋ͷ͸NodeΛ੍͢Δ • generator / yield => ؔ਺ͷ్தͰࢭΊΔͱ͍͏generatorؔ਺ͷಛੑΛར༻ͨ͠ॲ ཧɺ ES2015Ͱ༗ޮʹɻco΍koaͱ͔͕࠾༻ͯ͠Δɻ • async await => ௒৽੕ɺ ESnext ͰఏҊத
13. ͲΕ͕Ұ൪͍͍ͷΑʁ • έʔεόΠέʔε • callback => ୯७ɻͨͩ͠஍ࠈΛݟΔ͕࣌͋Δɻ • Promise => ES2015 Ͱೖͬͨඪ४ඇಉظॲཧ • Stream => Node.js ͷதͰ෯Λར͔͍ͤͯΔ࿈ଓͨ͠σʔλΛѻ͏ͨ ΊͷIOʹಛԽͨ͠ॲཧ • generator / yield => ES2015ͰೖͬͨएׯHackyͳॲཧ • async await => ಥ೗ݱΕͨ௒৽੕ɺ ESnext ͰఏҊத ͪΐ·Ͳ͞ΜٖਓԽ͓ئ͍க͠·͢ʂʂʂʂ
14. ͱΓ͋͑ͣɺଌͬͯΈΑ͏ • file copy ॲཧ (খ͍͞ϑΝΠϧίϐʔ 1KB x 1000) • callback => 0.10sec • Promise => 0.10sec • Stream => 0.09sec • generator/yield => 0.11sec
15. ͱΓ͋͑ͣɺଌͬͯΈΑ͏ • file copy ॲཧ (খ͍͞ϑΝΠϧίϐʔ 1KB x 1000) • callback => 0.10sec • Promise => 0.10sec • Stream => 0.09sec • generator/yield => 0.11sec มΘΒͳ͍ʜ
16. ͱΓ͋͑ͣɺଌͬͯΈΑ͏ • file copy ॲཧ (ൺֱతେ͖͍ϑΝΠϧίϐʔ 15MB) • callback => 1.51sec • Promise => 1.54sec • Stream => 1.05sec • generator/yield => 1.59sec
17. ͱΓ͋͑ͣɺଌͬͯΈΑ͏ • file copy ॲཧ (ൺֱతେ͖͍ϑΝΠϧίϐʔ 15MB) • callback => 1.51sec • Promise => 1.54sec • Stream => 1.05sec • generator/yield => 1.59sec 4USFBN଎͍
18. ͱΓ͋͑ͣɺଌͬͯΈΑ͏ • ੑೳଌఆ݁Ռ • Stream > callback ≒ Promise ≒ generator • େ͖͍ϑΝΠϧʹͳΔ΄ͲϑΝΠϧॻ͖ग़͠ Λஞ࣍తʹॲཧͰ͖ΔͷͰStream଎͍ɻ
19. Stream࠷ߴʢʁʣ • ׳Εͯͳ͍ਓଟ͍ • ͋ͱϒϥ΢βͰ࢖͑ͳ͍ɻɻɻ
20. ׳Εͯͳ͍ਓଟ͍ • Node.js Ͱ͸͜͏͍͏֨ݴ͕͋Δ • ʰStreamΛ੍͢Δ΋ͷ͸NodeΛ੍͢Δʱ • ͔ͳΓύϑΥʔϚϯεʹؾΛ࢖ͬͯΔ͔Βੵ ۃతʹ࢖͍ͬͯ͘΂͖ (in Node)
21. ϒϥ΢βͰ࢖͑ͳ͍ɻɻɻ • ͦΕͳʁ • ఏҊ͞Ε͍ͯΔ͔Βʂʂʂ
22. ๻ͷߟ͑ํ /PEFKT
    σʔλۦಈ͔Ͳ͏͔ Y 4USFBN N ੑೳؾʹͳΔ Y 1SPNJTF Y HFOFSBUPS N 1SPNJTJGZ ͍ͨ͠ Y DBMMCBDL N N