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。

Transcript

1. Ͳͷඇಉظॲཧ͕ྑ͍
   ͷ͔উෛ
   @yosuke_furukawa
   

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2. Twitter: @yosuke_furukawa
   Github: yosuke-furukawa
   

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3. Node.js೔ຊϢʔβʔάϧʔϓ୅ද
   Node.js Evangelist / Node.js Collaborator
   

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4. ҰԠઆ໌
   • Node.js ʹ͸ͨ͘͞Μͷඇಉظॲཧ͕͋Δ
   • callback
   • Promise
   • Stream
   • generator / yield
   • (Ͱ͖ͨΒ) async await
   

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5. ͲΕ͕Ұ൪͍͍ͷΑʁ
   • έʔεόΠέʔε
   

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6. ͲΕ͕Ұ൪͍͍ͷΑʁ
   • έʔεόΠέʔε
   ΄Μͱʁʁʁ
   

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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
   

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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
   

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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
   

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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
    

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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
    

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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
    

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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
    

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14. ͱΓ͋͑ͣɺଌͬͯΈΑ͏
    • file copy ॲཧ (খ͍͞ϑΝΠϧίϐʔ 1KB x 1000)
    • callback => 0.10sec
    • Promise => 0.10sec
    • Stream => 0.09sec
    • generator/yield => 0.11sec
    

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15. ͱΓ͋͑ͣɺଌͬͯΈΑ͏
    • file copy ॲཧ (খ͍͞ϑΝΠϧίϐʔ 1KB x 1000)
    • callback => 0.10sec
    • Promise => 0.10sec
    • Stream => 0.09sec
    • generator/yield => 0.11sec
    มΘΒͳ͍ʜ
    

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16. ͱΓ͋͑ͣɺଌͬͯΈΑ͏
    • file copy ॲཧ (ൺֱతେ͖͍ϑΝΠϧίϐʔ 15MB)
    • callback => 1.51sec
    • Promise => 1.54sec
    • Stream => 1.05sec
    • generator/yield => 1.59sec
    

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17. ͱΓ͋͑ͣɺଌͬͯΈΑ͏
    • file copy ॲཧ (ൺֱతେ͖͍ϑΝΠϧίϐʔ 15MB)
    • callback => 1.51sec
    • Promise => 1.54sec
    • Stream => 1.05sec
    • generator/yield => 1.59sec
    4USFBN଎͍
    

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18. ͱΓ͋͑ͣɺଌͬͯΈΑ͏
    • ੑೳଌఆ݁Ռ
    • Stream > callback ≒ Promise ≒ generator
    • େ͖͍ϑΝΠϧʹͳΔ΄ͲϑΝΠϧॻ͖ग़͠
    Λஞ࣍తʹॲཧͰ͖ΔͷͰStream଎͍ɻ
    

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19. Stream࠷ߴʢʁʣ
    • ׳Εͯͳ͍ਓଟ͍
    • ͋ͱϒϥ΢βͰ࢖͑ͳ͍ɻɻɻ
    

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20. ׳Εͯͳ͍ਓଟ͍
    • Node.js Ͱ͸͜͏͍͏֨ݴ͕͋Δ
    • ʰStreamΛ੍͢Δ΋ͷ͸NodeΛ੍͢Δʱ
    • ͔ͳΓύϑΥʔϚϯεʹؾΛ࢖ͬͯΔ͔Βੵ
    ۃతʹ࢖͍ͬͯ͘΂͖ (in Node)
    

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21. ϒϥ΢βͰ࢖͑ͳ͍ɻɻɻ
    • ͦΕͳʁ
    • ఏҊ͞Ε͍ͯΔ͔Βʂʂʂ
    

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22. ๻ͷߟ͑ํ
    /PEFKT
    σʔλۦಈ͔Ͳ͏͔
    Y
    4USFBN
    N
    ੑೳؾʹͳΔ
    Y
    1SPNJTF
    Y
    HFOFSBUPS
    N
    1SPNJTJGZ
    ͍ͨ͠
    Y DBMMCBDL
    N
    N
    

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