よりよいネーミングを目指して / 20171003 #orecon_ios #akibaswift

俺コン Vol.1 / Day. 2 - connpass
https://orecon.connpass.com/event/64285/
での発表資料です。

# 参考資料

リーダブルコード ―より良いコードを書くためのシンプルで実践的なテクニック (Theory in practice) | Dustin Boswell, Trevor Foucher, 須藤 功平, 角 征典 |本 | 通販 | Amazon
https://www.amazon.co.jp/dp/4873115655

Amazon | 新装版 リファクタリング―既存のコードを安全に改善する― (OBJECT TECHNOLOGY SERIES) | Martin Fowler, 児玉 公信, 友野 晶夫, 平澤 章, 梅澤 真史 通販
https://www.amazon.co.jp/dp/427405019X

Transcript

1. ΑΓΑ͍
   ωʔϛϯάΛ໨ࢦͯ͠
   by.
   2017/10/3 Զίϯ Vol.1 / Day.2
   1
   

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2. takasek
   iOS Developer
   @takasek
   OSS
   ActionClosurable
   Notifwift౳
   2
   

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3. View Slide

4. View Slide

5. ͦ͜·Ͱໃ६͠ͳͯ͘΋…
   ΍ͬͯ·ͤΜ͔ʁ
   4 update() Ͱಛఆͷ৚݅Ͱ͸updateͤͣʹ໭
   Δ
   4 fetch() ͱ͍͍ͭͭUIͷߋ৽΋ͯ͠Δ
   4 ໊લʹࠔͬͯ func didReceive(hoge: Hoge)
   5
   

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6. ໃ६ίʔυΛ
   ͦͷ··ʹͯ͠͠·͏ཧ༝
   4 ΊΜͲ͍͘͞
   4 ಈ͍͍ͯΔίʔυʹ৮Γͨ͘ͳ͍
   4 ద੾ͳ໊લ͕ࢥ͍͔ͭͳ͍
   4 ·͋ɺશମΛಡΊ͹ཧղͰ͖Δ
   4 ผʹόά͡Όͳ͍
   6
   

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7. Ͱ΋ɺωʔϛϯάΛ
   ͦͷ··ʹ
   ͓ͯ͘͠ͱ…
   7
   

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8. 1
   1 ετϧʔϓޮՌ - Wikipediaɹhttps://ja.wikipedia.org/wiki/
   %E3%82%B9%E3%83%88%E3%83%AB%E3%83%BC%E3%83%97%E5%8A%B9%E6%9E%9C
   8
   

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9. ໃ६ίʔυ͸
   ίʔυϦʔσΟϯάΛ
   ஗͘͢Δ
   9
   

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10. ΋ͬͱةݥͳͷ͸ɺ
    ؔ܎ͳ͍ॲཧ͕ೖΓࠐΉ
    伱͕Ͱ͖Δ໰୊
    4 ܕ΍ϝιουͷ੹຿ͷൣғ͕ఆ·Βͳ͍
    4 ܕ΍ϝιου͕ංେԽ͢Δɾॲཧ͕֤ॴʹ෼ࢄ
    ͢Δ
    4 ࠷ѱɺόά͕࢓ࠐ·ΕΔ
    10
    

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11. 4 update() Ͱಛఆͷ৚݅Ͱ͸updateͤͣʹ໭
    Δ
    4 σʔλߋ৽ޙ΋ը໘͸ߋ৽͞Εͳ͍…
    ͱࢥͬͨΒॲཧ్͕தͰguard͞Εͯͨ !
    4 fetch() ͱ͍͍ͭͭUIͷߋ৽΋ͯ͠Δ
    4 ࢥΘ͵࣌ʹදࣔ͞ΕΔAlert ⚠
    4 ໊લʹࠔͬͯ func didReceive(hoge: Hoge)
    4 isFetching: Bool ͷ؅ཧՕॴ͕෼ࢄʂ #
    11
    

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12. ໊લ͕;Θͬͱͯ͠Δ͔Β
    ༨ܭͳ͜ͱΛͯ͠͠·͏
    12
    

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13. Α໊͍લΛ
    ͚ͭΑ͏✨
    13
    

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14. Ͱ΋ɺͲ͏΍ͬͯʁ
    14
    

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15. ʮ໊લʹ৘ใΛ٧ΊࠐΉʯ 2
    1. ໌֬ͳ୯ޠΛબͿ
    2. ൚༻తͳ໊લΛආ͚Δʢ͋Δ͍
    ͸ɺ࢖͏ঢ়گΛબͿʣ
    3. ந৅తͳ໊લΑΓ΋۩ମతͳ໊લ
    Λ࢖͏
    4. ઀ඌࣙ΍઀಄ࣙΛ࢖ͬͯ৘ใΛ௥
    Ճ͢Δ
    5. ໊લͷ௕͞ΛܾΊΔ
    6. ໊લͷϑΥʔϚοτͰ৘ใΛ఻͑Δ
    2 ʮϦʔμϒϧίʔυʯDustin Boswell, Trevor
    Foucher, 2012 P10
    15
    

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16. ʮ໊લʹ৘ใΛ٧ΊࠐΉʯᶃ
    ໌֬ͳ୯ޠΛબͿ
    4 ❌ HogeStorage.set(fuga)
    ⭕ HogeStorage.store(fuga)
    4 ❌ RxSwift.Observable
    ⭕ RxSwift.Single as you can!
    16
    

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17. ʮ໊લʹ৘ใΛ٧ΊࠐΉʯᶃ
    ໌֬ͳ୯ޠΛબͿ
    ❌
    employees.remove(x)
    view.dismiss(false)
    let text = words.split(12)
    ⭕
    employees.remove(at: x)
    view.dismiss(animated: false)
    let text = words.split(maxSplits: 12)
    17
    

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18. ʮ໊લʹ৘ใΛ٧ΊࠐΉʯᶄ
    ൚༻తͳ໊લΛආ͚Δ
    ʢ͋Δ͍͸ɺ࢖͏ঢ়گΛબͿʣ
    ❌
    final class HogeViewController {
    private let margin: CGFloat = 2.0
    private let defaultSize = CGSize(width: 100, height: 50)
    ...
    }
    !ԿͷϚʔδϯͱαΠζ΍ͶΜ
    18
    

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19. ʮ໊લʹ৘ใΛ٧ΊࠐΉʯᶄ
    ൚༻తͳ໊લΛආ͚Δ
    ʢ͋Δ͍͸ɺ࢖͏ঢ়گΛબͿʣ
    ⭕
    func calculateComponentWidth
    (paralleling contentSizes: [CGSize]) -> CGFloat {
    return contentSizes.reduce(margin) { result, size in
    let margin: CGFloat = 2
    result + size.width + margin
    }
    }
    !Ͱ΋͜ΕͳΒڐͤΔɻείʔϓ͕ڱ͍ͷͰɻ
    19
    

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20. ʮ໊લʹ৘ใΛ٧ΊࠐΉʯᶄ
    ൚༻తͳ໊લΛආ͚Δ
    ʢ͋Δ͍͸ɺ࢖͏ঢ়گΛબͿʣ
    ⭕
    var userID: Int? {
    switch self.userState {
    case .id(id): return id
    case .entity(e): return e.id
    case .unavailable: return nil
    }
    }
    ͋͑ͯࡶͳ໊લΛ͚ͭͯʮҰ࣌తͳ΋ͷʯͩͱࣔ͢
    20
    

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21. ʮ໊લʹ৘ใΛ٧ΊࠐΉʯᶅ
    ந৅తͳ໊લΑΓ΋
    ۩ମతͳ໊લΛ࢖͏
    ❌
    class HogeListViewController : UIViewController {
    ...
    func fetch()
    func fetchBackground()
    func fetchReally(_ id: String, show: Bool)
    ...
    }
    ͲΕ͕Ͳ͏͍͏໾ׂʁ!
    21
    

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22. class HogeListViewController : UIViewController {
    /// ௨৴ͯ͠ɺࣦഊͨ͠ΒΞϥʔτΛදࣔ͢Δ
    func fetch() {
    fetchReally(textField.text!, show: true)
    }
    /// ௨৴ͯ͠ɺࣦഊͯ͠΋Ξϥʔτ͸දࣔ͠ͳ͍
    func fetchBackground() {
    fetchReally(textField.text!, show: false)
    // !Ͳ͏΍ΒʮΞϥʔτΛදࣔ͠ͳ͍ʯ͔Βbackgroundͱ͍͏Β͍͠ɻӕͩΖ!?
    }
    func fetchReally(_ id: String, show: Bool) {
    api.fetch(id) { [weak self] models in
    self?.didReceive(models: models, showsAlertIfFailed: show)
    }
    // !ʮ۩ମతͳ௨৴ॲཧ͕ॻ͍ͯ͋Δʯ͔Βreallyͱ͍͏Β͍͠
    }
    }
    22
    

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23. ʮ໊લʹ৘ใΛ٧ΊࠐΉʯᶅ
    ந৅తͳ໊લΑΓ΋
    ۩ମతͳ໊લΛ࢖͏
    ❌
    func fetch()
    func fetchBackground()
    func fetchReally(_ id: String, show: Bool)
    ⭕
    func startFetchingHogesWithFailureAlert()
    func startFetchingHogesWithoutFailureAlert()
    func fetchHoges(withID id: String, showsAlertIfFailed: Bool)
    23
    

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24. ʮ໊લʹ৘ใΛ٧ΊࠐΉʯᶆ
    ઀ඌࣙ΍઀಄ࣙΛ࢖ͬͯ
    ৘ใΛ௥Ճ͢Δ
    ❌
    let text1 = "100%25%E5%8B%87%E6%B0%97"
    let text2 = text1.removingPercentEncoding! // "100%༐ؾ"
    let text3 = text2.removingPercentEncoding! // CRASH"
    ⭕
    let encodedText = "100%25%E5%8B%87%E6%B0%97"
    let decodedText = encodedText.removingPercentEncoding! // "100%༐ؾ"
    // ΋͏$͸decodeࡁΈͩͱΘ͔Δ
    24
    

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25. ʮ໊લʹ৘ใΛ٧ΊࠐΉʯᶇ
    ໊લͷ௕͞ΛܾΊΔ
    ௕໊͍લͷೖྗࣗମ͸໰୊͡Όͳ͍ɻίʔυิ׬͕͋
    Δ͔Βɻ
    !লུܗʢbackend→beͱ͔ʣ͸఻ΘΒͳ͍͔Βආ͚Δɻ
    25
    

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26. ʮ໊લʹ৘ใΛ٧ΊࠐΉ¥ʯᶇ
    ໊લͷ௕͞ΛܾΊΔ
    Ͱ΋ɺෆཁͳ୯ޠ͸౤ࣺ͛ͯΔɻʢSwift3 ͸౤ࣺ͛ͯࡇΓͰͨ͠Ͷʂʣ
    26
    

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27. ʮ໊લʹ৘ใΛ٧ΊࠐΉʯᶈ
    ໊લͷϑΥʔϚοτͰ৘ใΛ఻͑Δ
    SwiftͰݴ͑͹…
    4 େจࣈ࢝·Γ͸ܕ໊ɺͦΕҎ֎͸খจࣈ࢝·Γ
    4 ΞϯμʔείΞ࢝·ΓͷAPI͸publicͳ΋ͷͰ
    ͸ͳ͍
    ྫ: _kvcKeyPathString ໰୊
    https://bugs.swift.org/browse/SR-5220
    27
    

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28. Ҏ্͕ʮ໊લʹ৘ใΛ٧ΊࠐΉʯ
    Ͱͨ͠
    1. ໌֬ͳ୯ޠΛબͿ
    2. ൚༻తͳ໊લΛආ͚Δʢ͋Δ͍͸ɺ࢖͏ঢ়گΛબͿʣ
    3. ந৅తͳ໊લΑΓ΋۩ମతͳ໊લΛ࢖͏
    4. ઀ඌࣙ΍઀಄ࣙΛ࢖ͬͯ৘ใΛ௥Ճ͢Δ
    5. ໊લͷ௕͞ΛܾΊΔ
    6. ໊લͷϑΥʔϚοτͰ৘ใΛ఻͑Δ
    28
    

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29. ʮϦϑΝΫλϦϯάʯ
    ΋͍͍͜ͱݴͬͯͨ
    "ϝιου໊ʹ͸ɺ಺෦ͰͲͷ
    Α͏ʹॲཧΛ͍ͯ͠Δ͔Ͱͳ
    ͘ɺͦͷίʔυ͕ԿΛ͢Δͷ
    ͔ͱ͍͏ҙਤΛࣔ͠·͢ɻ"4
    4 ʮ৽૷൛ɹϦϑΝΫλϦϯάɹطଘͷίʔυΛ҆શ
    ʹվળ͢Δʯ2014೥ P77
    29
    

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30. Swift ͷ API design guideline ʹै͏
    https://swift.org/documentation/api-design-guidelines/#naming
    4 ྲྀெͳӳจʹݟ͑ΔΑ͏ʹ
    4 ม਺ɾҾ਺ɾ෇ଐܕͷωʔϛϯά͸ɺͦͷ੍໿ΑΓ΋໾ׂʹԠͯ͡ߦ͏
    4 ϝιου໊ͷ඼ࢺΛɺ෭࡞༻͋Δͳ͠ͰมԽͤ͞Δ
    4 ෭࡞༻ͳ͠: ໊ࢺɺಈࢺͷաڈ෼ࢺɺݱࡏ෼ࢺΛ࢖͏
    4 e.g. array.sorted
    4 ෭࡞༻͋Γ: ಈࢺͷ໋ྩܗΛ࢖͏ɻ͋Δ͍͸ form Λ಄ʹ͚ͭΔ
    4 e.g. array.sort ɹ/ɹ y.formUnion()
    4 લྫΛ࠾༻͠·͠ΐ͏
    4 etc...
    30
    

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31. Swift Foundation / Cocoaͷྲّྀʹ
    ै͏
    API design guidelineͷ "લྫΛ࠾༻͠·͠ΐ͏" Λ࠾༻͠·͠ΐ͏
    4 Bool ܕ ͸ isʙ ɺcanʙ ɺneedsʙ ͳͲͰ࢝·Δ
    4 delegate ϝιουͷ໊෇͚ํ
    4 ❌ func willBlog(_ blog: Blog)
    ⭕ func atendeeWillBlog(_ blog: Blog)
    4 APIΛશମݕࡧͰ͖ΔΑ͏ʹ͓ͯ͘͠ͱศར
    4 https://developer.apple.com/search/?q={query}
    &type=Reference
    31
    

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32. ͦ΋ͦ΋
    ద੾ͳωʔϛϯά͕
    Ͱ͖ͳ͍ྫ΋͋Δ
    32
    

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33. class HogeListViewController : UIViewController {
    ...
    func startFetchingHogesWithFailureAlert() {
    fetchHoges(withID: textField.text!,
    showsAlertIfFailed: true)
    }
    func startFetchingHogesWithoutFailureAlert() {
    fetchHoges(withID: textField.text!,
    showsAlertIfFailed: false)
    }
    func fetchHoges(withID id: String,
    showsAlertIfFailed: Bool) {
    api.fetchHoges(withID: id) { [weak self] hoges in
    self?.didReceive(
    hoges: hoges,
    showsAlertIfFailed: showsAlertIfFailed
    )
    }
    }
    ...
    }
    33
    

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34. ద੾ͳωʔϛϯά͕Ͱ͖ͳ͍ྫᶃ
    ඇಉظॲཧ
    func fetchHoges(withID id: String,
    showsAlertIfFailed: Bool) {
    api.fetchHoges(withID: id) { [weak self] hoges in
    self?.didReceive(
    hoges: hoges,
    showsAlertIfFailed: showsAlertIfFailed
    )
    }
    }
    !fetchޙͷ׬ྃॲཧ΋୲͍ͬͯΔΜ͔ͩΒɺ
    ɹfetch ͬͯϝιου໊͚ͩͰ͸͓͔͘͠ͳ͍ʁ
    34
    

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35. ߏ଄Խϓϩάϥϛϯάͷେݪଇ
    ϝιου͸
    ೖޱ(Ҿ਺) ͱ ग़ޱ(໭Γ஋) Λ࣋ͭ
    ͔͠͠ඇಉظॲཧͷ݁Ռ͸
    ໭Γ஋ ʹ൓ө͞Εͳ͍
    35
    

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36. Ҿ਺͔໭Γ஋Ͱ
    ඇಉظॲཧ݁ՌΛड͚ΒΕΔ
    σβΠϯύλʔϯΛ࢖͓͏
    36
    

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37. ద੾ͳωʔϛϯά͕Ͱ͖ͳ͍ྫᶃ
    ඇಉظॲཧ
    ඇಉظॲཧ͸ callback ΍ Promiseύλʔϯ Λ࢖ͬͯ
    Α͏΍͘ਖ਼͘͠ݴ͍දͤΔ
    !
    func fetchHoges(withID id: String, showsAlertIfFailed: Bool)
    "callback
    func fetchHoges(withID id: String, completion: ([Hoge] -> Void))
    #promise
    func fetchHoges(withID id: String) -> RxSwift.Single<[Hoge]>
    37
    

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38. ద੾ͳωʔϛϯά͕Ͱ͖ͳ͍ྫᶄ
    ʁʁʁʁʁʁʁʁʁ
    func postProfileWith(name: String?,
    address: String?,
    tel: String?,
    profileImage: UIImage?,
    profileImageURL: URL?)
    -> RxSwift.Single
    γϯϓϧͰ෼͔Γ΍͍͢ϝιου໊…
    38
    

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39. ద੾ͳωʔϛϯά͕Ͱ͖ͳ͍ྫᶄ
    ʁʁʁʁʁʁʁʁʁ
    func postProfileWith(name: String?,
    address: String?,
    tel: String?,
    profileImage: UIImage?,
    profileImageURL: URL?)
    -> RxSwift.Single
    γϯϓϧͰ෼͔Γ΍͍͢ϝιου໊…
    ͬͯɺຊ౰ʁ
    39
    

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40. ద੾ͳωʔϛϯά͕Ͱ͖ͳ͍ྫᶄ
    Ҿ਺ͷදݱྗ͕ऑ͍
    func postProfileWith(name: String?,
    address: String?,
    tel: String?,
    profileImage: UIImage?,
    profileImageURL: URL?)
    -> RxSwift.Single
    4 Optional͹͔Γ͚ͩͲɺඞਢύϥϝʔλ͸Կͳͷ͔
    4 tel ☎ ͸Ͳ͏͍͏ϑΥʔϚοτͰจࣈྻԽ͢Ε͹͍͍ͷ͔
    4 Կނ profileImage ͱ profileImageURL ͕྆ํ͋Δͷ͔ɻͲͪ
    Β΋౉ͨ͠Βɺ͋Δ͍͸ͲͪΒ΋౉͞ͳ͔ͬͨΒͲ͏ͳΔͷ͔ɻ
    40
    

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41. Ҿ਺΋ωʔϛϯάͷ಺
    (໭Γ஋΋)
    41
    

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42. Ҿ਺ͷදݱྗΛߴΊΔ
    func postProfileWith(name: String?,
    address: String?,
    tel: String?,
    profileImage: UIImage?,
    profileImageURL: URL?)
    -> RxSwift.Single
    ɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹ!
    func postProfileWith(textData: ProfileTextData?,
    imageData: ProfileImageData)
    -> RxSwift.Single
    42
    

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43. // ͢΂ͯͷཁૉ͕ඞཁͳ৔߹ (AND) ͸ struct ͰදݱͰ͖Δ
    struct ProfileTextData {
    let name: String
    let address: String
    let tel: Tel?
    }
    // ͍ͣΕ͔ͷཁૉ͕ඞཁͳ৔߹ (OR) ͸ enum ͰදݱͰ͖Δ
    enum ProfileImageData {
    case image(UIImage)
    case url(URL)
    }
    43
    

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44. Ҿ਺ͷදݱྗΛߴΊΔ
    func postProfileWith(textData: ProfileTextData?,
    imageData: ProfileImageData)
    -> RxSwift.Single
    4 ProfileTextData (name & address & tel?) ͸
    4 ἧ͑ͯ౉͢ or ׬શεϧʔ
    4 ProfileImageData (UIImage | URL) ͸
    4 ͍ͣΕ͔Λ౉͢
    ͳΔ΄Ͳʂ!
    44
    

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45. ద੾ͳ໊લΛߟ͑Δ
    ⊃
    ઃܭͷݟ௚͠
    45
    

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46. = ϦϑΝΫλϦϯά
    46
    

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47. ਖ਼໊͘͠෇͚Α͏ͱ͢Δͱ
    ϝιουͷ໊લ͕
    ΍ͨΒ௕͔ͬͨΓ΅Μ΍Γ͢Δ!
    →❌
    ෆਖ਼֬Ͱ΋
    ୹͘ཁ໿ͪ͠Ό͓͏"
    47
    

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48. ਖ਼໊͘͠෇͚Α͏ͱ͢Δͱ
    ϝιουͷ໊લ͕
    ΍ͨΒ௕͔ͬͨΓ΅Μ΍Γ͢Δ!
    →⭕
    ϝιουͷ໾ׂ͕େ͖͗͢
    ͭ·ΓϦϑΝΫλϦϯά͕
    ඞཁͩͱ͍͏αΠϯͩʂ"
    48
    

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49. ʮϝιουΦϒδΣΫτʯ
    ϝιουࣗ਎ → ໊ࢺԽͯ͠ܕ(ΦϒδΣΫτ) ʹ
    શͯͷϩʔΧϧม਺ → ܕͷϓϩύςΟ ʹ
    ϝιου → ܕ಺ͷϝιου܈ ʹ
    class ProfilePoster {
    let textData: ProfileTextData?
    let imageData: ProfileImageData
    func run() -> RxSwift.Single
    private func ...
    }
    49
    

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50. ʮಛੑͷԣ࿀ูʯ
    ʢ͋Δϝιου͕ɺࣗ෼ͷΫϥεΑΓ΋ଞͷΫϥεʹڵຯΛ࣋ͭʯঢ়ଶʣ
    ❌
    class ProfilePoster {
    ...
    private func isTelValid(tel: String) -> Bool {
    return (try! NSRegularExpression(pattern: "^[0-9]+-[0-9]+-[0-9]+$"))
    .firstMatch(in: tel,
    range: NSRange(
    location: 0,
    length: (tel as NSString).length
    )) != nil
    }
    }
    ※isTelValid(tel:) ͷڵຯ͸ ʮϓϩϑΟʔϧͷฤूը໘ʯͰ͸ͳ͘ʮ☎ి࿩൪߸ʯ
    50
    

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51. ʮಛੑͷԣ࿀ูʯ
    ʢ͋Δϝιου͕ɺࣗ෼ͷΫϥεΑΓ΋ଞͷΫϥεʹڵຯΛ࣋ͭʯঢ়ଶʣ
    ☎͕ڵຯͷத৺Ͱ͋ΔܕΛ࡞Γɺ isTelValid(tel:) ΛҠಈ
    ⭕
    struct Tel {
    let value: String
    var isValid: Bool {
    return try! value.matches(pattern: "^[0-9]+-[0-9]+-[0-9]+$")
    // ※ String.matches(pattern:) ͸ String ʹੜ΍ͨ͠ extension
    }
    }
    51
    

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52. ओޠͱͳΔܕʹॲཧΛୗ͢͜ͱͰɺ
    ໌ྎ؆ܿͳωʔϛϯάʹͳΔ
    !before!
    ProfilePoster.isTelValid(tel: String) -> Bool
    "after"
    Tel.isValid: Bool
    4 ॲཧର৅͕selfͱͳΔ
    4 ϝιουج෦ʹॻ͍͍ͯͨॲཧର৅Λɺܕࣗ਎͕આ໌ͯ͘͠Ε
    Δ
    4 ॲཧର৅Λ͋ΒΘ͢Ҿ਺΋ফ͑Δ
    52
    

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53. ͪͳΈʹ
    Tel.isValid: Bool ΑΓ΋ྑ͍ઃܭ:
    init࣌ʹόϦσʔτͯ͠ɺͦ΋ͦ΋ෆਖ਼ͳ Tel ܕ
    Λ࡞Εͳ͍Α͏ʹ͢Δ
    struct Tel {
    enum Error: Swift.Error {
    case invalidFormat
    }
    let value: String
    init(value: String) throws {
    guard try value.matches(pattern: "^[0-9]+-[0-9]+-[0-9]+$") else {
    throw Error.invalidFormat
    }
    self.value = value
    }
    }
    53
    

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54. ܕ
    ʹඋΘΔදݱྗ!
    54
    

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55. ΦϒδΣΫτࢦ޲Ͱॻ͘ݶΓ
    ϝιου΋ϓϩύςΟ΋
    ԿΒ͔ͷܕͷ
    ϝϯό
    55
    

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56. ΑΓྑ͍ωʔϛϯάͷͨΊʹ͸
    "ԿΛ͢Δ/ԿͰ͋Δ" ͚ͩͰͳ͘
    "୭͕/୭ͷ" Λҙࣝ͢Δ
    56
    

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57. Happy Naming!!
    57
    

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58. ͓·͚
    ΑΓ๛͔ͳ
    ωʔϛϯάͷͨΊʹ
    58
    

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59. returns Optional vs throws
    struct Tel {
    enum Error: Swift.Error {
    case invalidFormat
    }
    let value: String !
    init(value: String) throws {
    guard try value.matches(pattern: "^[0-9]+-[0-9]+-[0-9]+$") else {
    throw Error.invalidFormat
    }
    self.value = value
    }
    }
    init?(value: String) ͱ͍͏ख΋͋Δ͚Ͳ…ʁ
    59
    

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60. returns Optional vs throws
    returns Optional
    4 ! ͓खܰ؆୯ʹѻ͑Δ
    4 " ෇Ճ৘ใ͕๡͍͠
    ྫ֎ॲཧ(throws)
    4 !ʮࣦഊ͠͏Δʯ͜ͱΛ໌֬ʹදͤΔ
    4 ! try? ߏจͰOptionalʹม׵Մೳ
    4 ! Error Λఆٛͯ͠ࡉ΍͔ʹࣦഊݪҼΛ఻͑ΒΕΔ
    4 " Error Λఆٛ͢Δඞཁ͕͋Δ
    60
    

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61. ݴޠػೳΛۦ࢖͠Α͏
    4 ࣗ෼ࣗ਎ͷܕΛฦ͢static func
    4 operator
    4 ه߸ʹΑΔॲཧΛఆٛ͢Δ
    4 લஔɾதஔɾޙஔ
    4 subscript
    4 e.g.ɹ reversiBoard[x: 10, y: 8]
    4 ෳ਺ͷҾ਺ɺϥϕϧ෇༩΋Մೳ
    61
    

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62. ίϚϯυɾΫΤϦ෼཭ݪଇ
    (CQRS)
    4 ίϚϯυʢ໭Γ஋ͳ͠ɺ෭࡞༻Λى͜͢ʣ
    4 ΫΤϦʢ໭Γ஋Λظ଴ɺԿ౓ݺΜͰ΋ಉ݁͡Ռ(ႈ
    ౳)ʣ
    Λ෼͚Δͱઃܭ͕͖ͬ͢Γ͢ΔΑͱ͍͏࿩
    var canFetch: Bool
    func startFetching(id: Int) -> Void
    let hoges: Rx.Observable<[Hoge]>
    62
    

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63. Happy Happy
    Naming!!
    63
    

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