gotandajs-11-nodejs-recursive-readdir

Gotanda.js #11 in MobileFactory ( https://gotandajs.connpass.com/event/127779/ ) での発表資料です。

Transcript

1. Node.jsͰͷrecursive readdirΛߟ͑Δ
   ͋Β΍ @arayaryoma
   
   Gotanda.js #11 in Mobile Factory
   

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2. ࣗݾ঺հ
   ͋Β΍ / Ѩ෦ ྇ຏ
   
   @arayaryoma
   
   @arayaryoma
   
   https://araya.dev
   
   גࣜձࣾϔϚλΠτ / ෭ۀϑϦʔϥϯε
   
   JavaScript/TypeScript/Go/Kotlin
   
   Angular/React/ReactNative/Next.js/Nest.js
   

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3. ͔͜͜Β໨ࠇํ໘ʹ10෼͘Β͍า͍ͨͱ͜ΖʹΦϑΟε͕͋ΔձࣾͰಇ͍͍ͯ·͢
   
   ޒ൓ాͷ޷͖ͳ͓ళ͸ϗοτεϓʔϯͰ͢
   

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4. ୡ੒͍ͨ͜͠ͱ
   ͜ͷΑ͏ͳσΟϨΫτϦͰ
   
   filesΑΓԼʹ͋ΔશͯͷϑΝΠϧͷϦετΛऔಘ͍ͨ͠
   

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5. ·ͣߟ͑Δ͜ͱ
   fs.readdirʹΦϓγϣϯΛ౉͢ͱɺ΋͔͍͍ͯ͠͠ײ͡ʹऔΕΔͷͰ͸ͳ͍͔
   

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6. ·ͣߟ͑Δ͜ͱ
   ౰વͦΜͳந৅తͳ΋ͷ͸ͳ͍
   

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7. ੈͷதʹస͕͍ͬͯΔղܾࡦ
   • https://github.com/jergason/recursive-readdir
   
   • https://stackoverflow.com/questions/5827612/node-js-fs-readdir-recursive-directory-search
   
   • https://gist.github.com/kethinov/6658166

   

   ͳͲ…
   GoogleͰʮnode.js recursive readdirʯͱݕࡧ͢Δͱɺ
   
   ͍͔ͭ͘ղܾࡦ΍ϥΠϒϥϦ͕ݟ͔ͭΔ
   

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8. ੈͷதʹస͕͍ͬͯΔղܾࡦ
   ͜ΕΒͷ࣮૷ྫͰ͸ɺ͓͓·͔ʹ
   1. fs.readdirͰσΟϨΫτϦ௚ԼͷϑΝΠϧͷϦετΛऔಘ͢Δ
   
   2. 1ͷ݁ՌΛϧʔϓ΍ΠςϨʔλͰճ͠ɺ֤ϑΝΠϧͷύεΛfs.statؔ਺ʹ౉͠ɺ
   fs.StatsΦϒδΣΫτΛಘΔ
   
   3. fs.StatsΦϒδΣΫτʹ͸isDirectory()ϝιου͕͋Γɺ͜ΕͰର৅ͷϑΝΠϧ͕
   σΟϨΫτϦ͔Ͳ͏͔൑ఆ͢Δ
   
   4. 3ͷ݁ՌɺσΟϨΫτϦͩͬͨ৔߹͸ͦͷσΟϨΫτϦʹ͍ͭͯɺ1~3Λߦ͏

   3ͷ݁ՌɺϑΝΠϧͩͬͨ৔߹͸഑ྻfilesʹ௥Ճ͢Δ
   
   5. ϧʔϓ͕ऴΘͬͨΒ഑ྻfilesΛฦ͢
   ͱ͍͏ํ๏͕ͱΒΕ͍ͯΔɻ
   

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9. ੈͷதʹస͕͍ͬͯΔղܾࡦ
   ΤϥʔϋϯυϦϯά౳͸ແࢹͨ͠࠷খݶͷ࣮૷ྫ
   
   ಡΈ΍͢͞ͷͨΊʹಉظ࣮ߦ͞ΕΔؔ਺Λ࢖༻
   

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10. ੈͷதʹస͕͍ͬͯΔղܾࡦ
    ݱࡏͷσΟϨΫτϦ௚ԼͷϑΝΠϧҰཡΛऔಘ
    

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11. ੈͷதʹస͕͍ͬͯΔղܾࡦ
    fs.statSync()Ͱfs.StatsΦϒδΣΫτΛऔಘ͠ɺ
    
    σΟϨΫτϦ͔Ͳ͏͔൑ఆɻ
    
    ϑΝΠϧͩͬͨ৔߹͸ϑΝΠϧϦετʹ௥Ճɻ
    

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12. ੈͷதʹస͕͍ͬͯΔղܾࡦ
    ࢠσΟϨΫτϦͷϦετΛϧʔϓͰճ͠ɺ
    
    ֤ࢠσΟϨΫτϦʹରͯؔ͠਺Λ࠶ؼݺͼग़͢͠Δɻ
    

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13. ੈͷதʹస͕͍ͬͯΔղܾࡦ
    ϑΝΠϧͷϦετΛฦ͢
    

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14. ੈͷதʹస͕͍ͬͯΔղܾࡦ
    ࣮ߦ݁Ռ
    

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15. Node.js v10.10Ҏ߱Ͱ͸fs.statΛ࢖Θͣʹॻ͚Δ
    fs.readdir()ʹ{withFileTypes: true}Λ౉͢ͱɺfiles͸fs.DirentΦϒδΣΫτͷ഑ྻʹͳΔ
    

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16. Node.js v10.10Ҏ߱Ͱ͸fs.statΛ࢖Θͣʹॻ͚Δ
    fs.DirentΦϒδΣΫτʹ͸isDirectory()΍
    isFile()ͳͲͷϝιου͕࣮૷͞Ε͍ͯΔ
    
    ϑΝΠϧ໊͸.nameͰऔಘͰ͖Δ
    
    -> ϑΝΠϧγεςϜίʔϧΛ1σΟϨΫτϦʹ͖ͭ
    
    1౓Ͱࡁ·͢͜ͱ͕Ͱ͖Δ
    https://github.com/nodejs/node/pull/22020
    

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17. fs.Dirent ΦϒδΣΫτΛ࢖࣮ͬͨ૷ྫ
    

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18. fs.Dirent ΦϒδΣΫτΛ࢖࣮ͬͨ૷ྫ
    {withFileTypes: true}Λࢦఆͯ͠
    
    fs.DirentΦϒδΣΫτΛಘΔ
    
    dirent.isDirectoryͰ
    
    σΟϨΫτϦ͔Ͳ͏͔൑ఆ
    
    1֊૚ʹ͖ͭ1౓ͷϑΝΠϧγεςϜίʔϧ
    

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19. fs.Dirent ΦϒδΣΫτΛ࢖࣮ͬͨ૷ྫ
    {withFileTypes: true}Λࢦఆͯ͠
    
    fs.DirentΦϒδΣΫτΛಘΔ
    
    dirent.isDirectoryͰ
    
    σΟϨΫτϦ͔Ͳ͏͔൑ఆ
    
    1֊૚ʹ͖ͭ1౓ͷϑΝΠϧγεςϜίʔϧ
    
    

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20. ඇಉظʹ͢Δ
    fs.readdir()ʹίʔϧόοΫؔ਺Λ౉ͯ݁͠ՌΛॲཧͯ͠΋͍͍͕ɺ
    
    Node.js v10 Ͱ͸ɺExperimental͕ͩfs Promises API͕ఏڙ͞Ε͍ͯΔ
    
    (v12Ͱ͸stable)
    

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21. fs Promises API
    
    

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22. fs Promises APIΛ࢖ͬͯॻ͖௚͢
    

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23. ·ͱΊ
    •ϥΠϒϥϦΛ࢖Θͳͯ͘΋ɺͦ͜·Ͱଟ͘ͳ͍هड़ྔͰrecursive readdir͸࣮ݱͰ͖Δɻ
    
    •Node.js v10.10Ҏ͕߱࢖͑Δ৔߹͸fs.DirentΦϒδΣΫτΛ׆༻ͯ͠

    ϑΝΠϧγεςϜίʔϧͷճ਺ΛݮΒ͢͜ͱ͕Ͱ͖Δɻ
    
    •fs Promises APIΛ༻͍Δ͜ͱͰɺϑΝΠϧγεςϜૢ࡞͕PromiseϕʔεͰॻ͚Δɻ
    
    •Node.js͸minor version updateͰศརͳAPI͕௥Ճ͞ΕΔ͜ͱ͕͋ΔͨΊɺ

    LTSͷ࠷৽Λ࢖͍ଓ͚Δબ୒ࢶ͕औΕΔͱྑ͍ɻ
    

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24. ิ଍: direntͱ͍͏֓೦ʹ͍ͭͯ
    dirent͸Linux Programmingʹ͓͍ͯɺϑΝΠϧͷ৘ใΛ࣋ͭߏ଄ମɻ
    
    readdirؔ਺͸͜ͷߏ଄ମΛฦ͢ɻ
    manϖʔδ( http://man7.org/linux/man-pages/man3/readdir.3.html )ΑΓɺglibcͰͷ࣮૷
    

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