ϑϩϯτΤϯυͷύϥμΠϜΛࢀߟʹόοΫΤϯυ։ൃΛ࠶ߟ͢Δ 5ZQF4DSJQUʹΑΔ (SBQI2-όοΫΤϯυ։ൃ גࣜձࣾ Ұٳ ҏ౻ ௚໵

K2VFSZظ .1"XJUIK2VFSZ ʮ+BWB4DSJQU͕ಘҙʯͳਓ͸͍͕ͨɺϑϩϯτΤϯυ όοΫΤϯυͱ͍͏໾ׂ෼୺͸ߦΘ Εͣɺશһ͕ಉ͡ྖҬΛ୲౰͍ͯͨ͠

7VFKTಋೖظ .1" 7VFϑϩϯτΤϯυ ʮϑϩϯτΤϯυΤϯδχΞʯʮόοΫΤϯυΤϯδχΞʯͱ͍͏໾ׂ෼୺͕গͣͭ͠ͳ͞Ε ΔΑ͏ʹ

/VYU࣌୅ /VYU (SBQI2-όοΫΤϯυ ʮϑϩϯτΤϯυʯʮόοΫΤϯυʯͷ໾ׂ෼୺͕໌֬ʹ ϑϩϯτΤϯυͷΈ։ൃΛ͢Δɺͱ͍͏୲౰ऀ΋

૒ํͷٕज़తؔ৺ࣄʹΪϟοϓ • ΞϓϦέʔγϣϯͷঢ়ଶ؅ཧϞσϧ • σβΠϯγεςϜ • ϓϦϨϯμϦϯά • ŋŋŋ ϑϩϯτΤϯυ όοΫΤϯυ • υϝΠϯϞσϧ • ϨΠϠʔυɾΞʔΩςΫνϟ • $234 • ŋŋŋ ૊৫ͷٕज़࿅౓্͕͕Ε͹্͕Δ΄Ͳɺؔ৺ࣄͷΪϟοϓ͕޿͕͍ͬͯͬͨ

͖͔͚ͬ • ৽نϓϩδΣΫτ্ཱ͕͕ͪΔ • ϑϩϯτΤϯυ͸ 3FBDU3FMBZ3FDPJM Λ࠾༻ • (SBQI2-όοΫΤϯυ ŋŋŋ ௕Β͘ 1ZUIPOͰɺΫϥεΛଟ༻ͨ͠ΫϦʔϯΞʔΩςΫνϟ తͳઃܭͰ΍͖͕ͬͯͨɺࠓճ͸Ͳ͏͢Δ͔

৽نϓϩμΫτ͸খ͞ͳνʔϜͰີ౓ߴٞ͘࿦ͯ͠࡞Γ͍ͨ • ސ٬ͷͲΜͳ໰୊ΛɺͲ͏ղܾ͍͔ͨ͠ ŋŋŋ σΟεΧογϣϯΛେࣄʹ͍ͨ͠ – ϑϩϯΤϯυɺόοΫΤϯυؔ܎ͳ͘ର৅υϝΠϯྖҬʹৄ͘͠ͳΓ͍ͨ – ͲΜͳମݧΛɺͲΜͳ 6*ͰɺͲ͏͍͏ϞσϧͰɺͲΜͳσʔλઃܭΛ࣮ͯ͠ݱ͢Δͷ͔ɻॳظ ϑΣʔζͰ͸શһ͕ͳΔ΂͘޿͘஌͓͖͍ͬͯͨ • ૣظʹ໾ׂ෼୺Λߦ͍͗͢Δͱɺؔ৺ࣄͷ෼அΛ༠ൃͯ͠͠·͏

3FBDUͰϑϩϯτΤϯυΛ։ൃ͔ͯ͠Βɺ όοΫΤϯυΛॻ͘ͱŋŋŋ • 3FBDUŋŋŋ খ͞ͳؔ਺Λ૊Έ߹Θͤͯએݴతʹॻ͍͍ͯ͘ • όοΫΤϯυ ŋŋŋ ΫϥεΛͨ͘͞Μॻ͍ͯɺϨΠϠʔΛލ͙ͱ %50Ͱͷ஋٧Ίସ͑Λߦͬ ͯɺJOUFSGBDFͰґଘੑͷٯసΛߦͬͯŋŋŋ – ʮŋŋŋϑϩϯτΤϯυͩͱ͜͏͍͏͜ͱɺ͋Μ·Γ΍Βͳ͍ΑͶʯ ։ൃ࣌ͷϝϯλϧϞσϧͷΪϟοϓ͕େ͖͍ ίϯςΩετεΠονͷෛ୲΋େ͖͍

όοΫΤϯυ։ൃͷ΍ΓํΛ࠶ߟͯ͠Έ͍ͨ • 3FBDUΛ࢖͍ͬͯΔͱϑϩϯτΤϯυ͸ബ͘ॻ͘͜ͱ͕Ͱ͖Δ • ؔ৺ࣄ͕ҧ͏ͷ͸౰વɻ͔ͱ͍ͬͯɺ΍Γํ͕ҧ͏ͷΛશٙ͘Θͳ͍ͷ΋Ͳ͏ͩΖ͏ ϑϩϯτΤϯυͷঢ়ଶ؅ཧ͸ෳࡶ ͦͷෳࡶͳ΋ͷΛͲ͏ѻ͏͔ɺݱ࣌఺Ͱ࠷ྑͷϞσϧͷͻͱ͕ͭ 3FBDUͷ͸ͣ ʮෳࡶͳঢ়ଶΛͲ͏ѻ͏͔ʯͱ͍͏؍఺ͰɺαʔόʔαΠυ΋ಉ͡Α͏ʹߟ͑ΒΕͳ͍ͷ͔ Α͠ɺ(SBQI2-όοΫΤϯ υ΋ 5ZQF4DSJQUͰॻ͍ͯΈ Α͏

վΊͯɺࡢࠓͷϑϩϯτΤϯυͷϓϩάϥϛϯάύϥμΠϜΛߟ͑ͯΈΔ https://zenn.dev/mizchi/articles/oop-think-modern

&MNΞʔΩςΫνϟ https://guide.elm-lang.jp/architecture/

update : Msg -> Model -> ( Model, Cmd Msg ) update msg model = case msg of ToggleLike -> ( { model | photo = Maybe.map toggleLike model.photo }, Cmd.none ) UpdateComment comment -> ( { model | photo = Maybe.map (updateComment comment) model.photo }, Cmd.none ) SaveComment -> ( { model | photo = Maybe.map saveNewComment model.photo }, Cmd.none ) LoadFeed (Ok photo) -> ( { model | photo = Just photo }, Cmd.none ) LoadFeed (Err _) -> ( model, Cmd.none ) viewLikeButton : Photo -> Html Msg viewLikeButton model = let buttonClass = if model.liked then ... div [ class "like-button" ] [ i [ class "fa fa-2x", class buttonClass, onClick ToggleLike ] [] ] &MN 7JFX͸ .PEFMΛඳըɻ Ϣʔβʔૢ࡞ʹԠͯ͡Πϕ ϯτΛૹΔͱŋŋŋ &MNϥϯλΠϜ͕ VQEBUFؔ਺ ΛݺͿɻؔ਺ʹ͸Πϕϯτͷछ ྨʹԠͨ͡Ϟσϧͷঢ়ଶભҠΛ هड़͓ͯ͘͠

ঢ়ଶભҠͷؔ਺ ֎քͱ΍Γͱ Γ *0 イベント コマンド

model -> model' model -> model' model -> model' ΠϕϯτΛܖػʹঢ়ଶ͕ભҠ͢Δ ŋŋŋ ࣌ܥྻʹج͍ͮͨঢ়ଶ

ঢ়ଶભҠͷؔ਺ ϥϯλΠϜ΍ϑ ϨʔϜϫʔΫ イベント コマンド Πϕϯτʹ൐͍ঢ়ଶΛભҠͤͯ͞ɺ͋ͱ͸ϑϨʔϜϫʔΫ΍ϥϯλΠϜʹ೚ͤΔ

3FEVY"QQMJDBUJPO%BUB'MPX https://redux.js.org/tutorials/essentials/part-1-overview-concepts

3FDPJM function TextInput() { const [text, setText] = useRecoilState(textState); const onChange = (event) => { setText(event.target.value); }; return ( ); }

3FDPJM • 3FEVYʹΑΔେ͖ͳάϩʔόϧεςʔτ͸ɺѻ͍ͮΒ͍ہ໘΋͋ͬͨ • ΑΓείʔϓΛڱ͘ɺখ͘͞ɺϩʔΧϧεςʔτ VTF4UBUF ಉ༷ʹϑοΫͰએݴతʹѻ͍ ͍ͨ &MNΞʔΩςΫνϟ΍ 3FEVYͰൃݟ͞Εͨྑ͍ϓϥΫςΟε͸౿ऻͭͭ͠ɺͰ͖Δݶ Γখ͞ͳείʔϓͰঢ়ଶΛѻ͍͚ͬͯΔͱྑͦ͞͏

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όοΫΤϯυͰ΋ಉ͡Α͏ʹʮ࣌ܥྻʹجͮ͘ঢ়ଶભҠʯͷࢹ఺Ͱߟ͑ΒΕͳ͍͔ • όοΫΤϯυͷੈքͷओͳʮঢ়ଶʯ ŋŋŋ υϝΠϯϞσϧͷঢ়ଶ • υϝΠϯϞσϧͷঢ়ଶΛભҠͤ͞ΔΠϕϯτ ŋŋŋ υϝΠϯΠϕϯτ

ͨͱ͑͹ʮ॓ധ༧໿ʯΛྫʹυϝΠϯϞσϧΛվΊͯߟ͑ͯΈΔ • ͲΜͳ؍఺ʹ஫໨ͯ͠ߟ͑ͯΈΔ΂͖͔ – σʔλߏ଄ – &3ਤ – Ϋϥεͷ࣮૷ – ը໘ • ͍ͣΕ΋੩తͳߏ଄ʹয఺Λ౰͍ͯͯΔɻࢹ఺Λม͑ͯΈ͍ͨ – ಈతͳ΋ͷŋŋŋυϝΠϯΠϕϯτ΍ঢ়ଶʹয఺Λ౰ͯͯΈΔͱ

ʮ༧໿ʯͷঢ়ଶભҠʹண໨ͯ͠ΈΔ ༧໿׬ྃ Χʔυܾࡁ ࡁΈ Ωϟϯηϧ ॓ധࡁΈ

৽ن༧໿͕׬ྃ͢Δલ͔ΒυϝΠϯϞσϧ͸ଘࡏ͍ͯ͠Δ ༧໿׬ྃ Ωϟϯηϧ ॓ധࡁΈ ೖྗ ݕূࡁΈ ೖྗະݕূ ࡏݿ֬อ ࡁΈ

ঢ়ଶ͸Կ͔͠ΒͷΠϕϯτΛܖػʹભҠ͢Δ ༧໿׬ྃ Ωϟϯηϧ ॓ധࡁΈ ೖྗ ݕূࡁΈ ೖྗະݕূ ࡏݿ֬อ ࡁΈ ༧໿Λ։࢝ͨ͠ ݕূ͕׬ྃͨ͠ ࡏݿΛ֬อͨ͠ ༧໿Λߦͬͨ Ωϟϯηϧ͞Εͨ ॓ധͨ͠

model -> model' model -> model' model -> model' ͓΍

྆୺͸֎෦ͱͷΠϯλϑΣʔε model -> model model -> model &WFOU)BOEMFS 8FC"QQͳΒ SPVUFS %#ʹอଘ͠ Ϩεϙϯε 6*

model -> model model -> model event &WFOU)BOEMFS 8FC"QQͳΒ SPVUFS %#ʹอଘ͠ Ϩεϙϯε 6* event event ֎ͷੈք ֎ͷੈք ֎ͷੈք Πϕϯτ ˠϞσϧͷঢ়ଶભҠ 🤔 Ͳ͔͜Ͱݟͨͳŋŋŋ

ঢ়ଶભҠͷؔ਺ ϥϯλΠϜ΍ϑ ϨʔϜϫʔΫ イベント コマンド ಉ͡

*0ঢ়ଶભҠ *0 Pure function Model -> Model *0 JOQVUMPBE *0 PVUQVU

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https://www.slideshare.net/ScottWlaschin/reinventing-the-transaction-script-ndc-london-2020

ϑϩϯτΤϯυͱόοΫΤϯυͷঢ়ଶ؅ཧ • ϑϩϯτΤϯυͷঢ়ଶ؅ཧ ŋŋŋ ओͳؔ৺ࣄ͸ʮΞϓϦέʔγϣϯͷঢ়ଶʯ • όοΫΤϯυͷঢ়ଶ؅ཧ ŋŋŋ ओͳؔ৺ࣄ͸ʮυϝΠϯϞσϧɺυϝΠϯΦϒδΣΫτͷঢ় ଶʯ ؅ཧ͍ͯ͠Δঢ়ଶͷίϯςΩετ͸ҧ͏΋ͷͷ ঢ়ଶ؅ཧͷϞσϧ͸ࣅͨΑ͏ʹߟ͑ΒΕΔͷͰ͸ͳ͍͔

ʮυϝΠϯΦϒδΣΫτͷঢ়ଶભҠΛએݴతʹهड़ͭͭ͠ *0͔Β෼཭͢Δʯ • ͜ͷίϯηϓτͰ࣮૷ • &MNΞʔΩςΫνϟ͓Αͼ '%%%ຊΛࢀߟʹ

͜ͷελΠϧͰΑ͘࢖͏΋ͷ • type / interface • λά෇͖ϢχΦϯ ௚࿨ܕ • 3FTVMUܕ • ΧϦʔԽ • ܕͷϒϥϯυԽ ίϯύχΦϯΦϒδΣΫτ

͋·Γ࢖Θͳ͍΋ͷ • class • ྫ֎ͷ throw – Error Ϋϥε͸࢖͍·͢

؆୯ͳϢʔεέʔεྫ

5BHΤϯςΟςΟ ू໿ϧʔτ ͷঢ়ଶભҠʹண໨͢Δ 7BMJEBUFE 6OWBMJEBUFE $SFBUFE ೖྗ͕͋ͬͨ ݕূͨ͠ ࡞੒ͨ͠ ˞͜͜Ͱͷʮ$SFBUFEʯ͸͋͘·ͰυϝΠϯΦϒδΣΫτ͕ l࡞੒ࡁΈzʹͳͬͨঢ়ଶͰ͋ͬͯɺσʔλϕʔεʹϨίʔυ Λ௥Ճͨ͠ɺͱ͍͏ঢ়ଶͰ͸ͳ͍

5BHΫϥεΛ࡞Δ export class Tag { state: 'Unvalidated' | 'Validated' | 'Created', id: TagId | undefined, groupId: RestaurantGroupId, label: string, icon: TagIcon | undefined, sortOrder: number | undefined, builtin: boolean | undefined }

export class Tag { state: 'Unvalidated' | 'Validated' | 'Created', id: TagId | undefined, groupId: RestaurantGroupId, label: string, icon: TagIcon | undefined, sortOrder: number | undefined, builtin: boolean | undefined } ঢ়ଶભҠલʹ͸֬ఆ͠ͳ͍ϓϩύςΟ͕ VOEFGJOFE ʹͳͬͯ͠·͏ŋŋŋ

interface UnvalidatedTag { kind: 'Unvalidated' groupId: string label: string icon?: { symbol: string; type: TagIconType; color?: string | null | undefined } | null | undefined } interface ValidatedTag { kind: 'Validated' groupId: RestaurantGroupId label: string icon: TagIcon } export interface CreatedTag { kind: 'Created' id: TagId groupId: RestaurantGroupId label: TagLabel icon: TagIcon sortOrder: number builtin: boolean } //※この型は実際には出番がないので使っていない export type Tag = UnvalidatedTag | ValidatedTag | CreatedTag ͦ͜Ͱঢ়ଶ͝ͱʹܕΛఆٛ͢Δ ঢ়ଶ͕ભҠ͢Δ υϝΠϯΠϕ ϯτ͕ൃੜ͢Δ͝ͱʹϞσϧͷ஋ ͕֬ఆ͍ͯ͘͠ͷ͕એݴͰ͖͍ͯ Δ

l.BLF*MMFHBM4UBUFT6OSFQSFTFOUBCMFz interface User { memberId: MemberId | undefined guestId: GuestId | undefined } interface Member { userId: MemberId } interface Guest { guestId: GuestId } type User = Member | Guest औΓಘΔ஋ͷछྨ਺͸֤ଐੑͷੵʹͳΔ ௚ੵ Y ɾ྆ํ VOEFGJOFE ɾ྆ํͷ஋͕ຒ·Δ ͱ͍͏࢓্༷͋Γಘͳ͍ঢ়ଶ͕ੜ·ΕΔ औΓಘΔछྨ਺͸֤ଐੑͷ࿨ ௚࿨ ࢓্༷͋Γಘͳ͍ঢ়ଶ͸දݱ͠ͳ͍ Ϩίʔυ͸ʮ͔ͭ "/% ʯ ϢχΦϯ͸ʮ·ͨ͸ 03 ʯ

ͪ͜ΒΑΓ΋ŋŋŋ export class Tag { state: 'Unvalidated' | 'Validated' | 'Created', id: TagId | undefined, groupId: RestaurantGroupId, label: string, icon: TagIcon | undefined, sortOrder: number | undefined, builtin: boolean | undefined }

interface UnvalidatedTag { kind: 'Unvalidated' groupId: string label: string icon?: { symbol: string; type: TagIconType; color?: string | null | undefined } | null | undefined } interface ValidatedTag { kind: 'Validated' groupId: RestaurantGroupId label: string icon: TagIcon } export interface CreatedTag { kind: 'Created' id: TagId groupId: RestaurantGroupId label: TagLabel icon: TagIcon sortOrder: number builtin: boolean } export type Tag = UnvalidatedTag | ValidatedTag | CreatedTag ͪ͜Βͷํ͕ɺ஋ͷ૊Έ߹Θͤύλʔϯ͕গͳ͘ݫີ

type validateTag = (model: UnvalidatedTag) => ValidatedTag const validateTag: validateTag = (model) => { // (省略: 値の validation ...) return { ...model, kind: 'Validated', groupId: RestaurantGroupId(model.groupId), icon: model.icon ? TagIcon(model.icon) : NoIcon(), } } ঢ়ଶΛભҠͤ͞Δεςοϓ ؔ਺

ঢ়ଶΛભҠͤ͞Δεςοϓ ؔ਺ type createTag = (model: ValidatedTag) => CreatedTag const createTag: CreatedTag = (model) => { return { ...model, kind: 'Created', id: generateTagId(), sortOrder: getTagSortOrder({ groupId: model.groupId }), builtin: false, } } ४උ͕੔ͬͯॳΊͯ஋͕֬ఆ ͢ΔͷΛࣗવʹهड़Ͱ͖Δ ͳ͓ getTagSortOrder ͸ *0͕͋Δ ͨΊ %*͍ͯ͠Δɻࠓճ͸ׂѪ

Ϟσϧͷܕɺؔ਺ͷܕʹΑͬͯঢ়ଶભҠΛએݴతʹهड़͢Δ 7BMJEBUFE 6OWBMJEBUFE $SFBUFE (model: UnvalidatedTag) => ValidatedTag (model: ValidatedTag) => CreatedTag

ݸผʹఆٛͨ͠ঢ়ଶભҠͷؔ਺Λܨ͍͛ͨ • Ͱ΋ɺܭࢉ͸ʮ్தͰࣦഊ͢ΔʯՄೳੑ͕͋Δ – ͨͱ͑͹υϝΠϯϞσϧͷࣄલ৚݅Λຬͨ͞ͳ͍Τϥʔ – 7BMJEBUJPO&SSPSŋŋŋ – .BY5BH-JNJU&YDFFEFEʜ • ʮ్தͰࣦഊ͢Δʯ͜ͱΛܕͰએݴͰ͖ͳ͍͔ ˠ 3FTVMUܕ

3FTVMUܕͰࣦഊͷՄೳੑͷ͋ΔܭࢉΛҰຊಓʹ߹੒͢Δ import { Result, ok, err } from 'neverthrow' function itsUnder100(n: number): Result { return n <= 100 ? ok(n) : err(new Error('100より大きい数字です')) } function itsEven(n: number): Result { return n % 2 == 0 ? ok(n) : err(new Error('奇数です')) } function itsPositive(n: number): Result { return n > 0 ? ok(n) : err(new Error('負数です')) } const result = ok(96).andThen(itsUnder100).andThen(itsEven).andThen(itsPositive) result.match( (n) => console.log(n), (error) => { throw error } )

3FTVMUܕͰঢ়ଶભҠؔ਺Λͭͳ͛ͯɺҰͭͷʮϫʔΫϑϩʔʯΛ࡞Δ 7BMJEBUFE5BH $SFBUFE5BH 6OWBMJEBUFE5BH 7BMJEBUFE5BH 8PSL'MPX

type validateTag = (model: UnvalidatedTag) => Result const validateTag: validateTag = (model) => { const groupId = RestaurantGroupId(model.groupId) const label = TagLabel(model.label) const icon = model.icon ? TagIcon(model.icon) : ok(NoIcon()) const values = Result.combine(tuple(groupId, label, icon)) return values.map(([groupId, label, icon]) => ({ ...model, kind: 'Validated', groupId, label, icon, })) } ঢ়ଶભҠͷ੒ޭ ࣦഊΛ 3FTVMUܕͰฦ͢Α͏ʹ͢Δ ஋ͷੜ੒ʹࣦഊ͢ΔՄೳੑ͕͋ΔͷͰɺ ͜ΕΒ΋ 3FTVMUܕΛฦ͢

3FTVMUܕͰঢ়ଶભҠؔ਺Λܨ͛ͯɺϫʔΫϑϩʔ υϝΠϯϩδοΫ Λ࡞Δ type WorkFlow = (model: UnvalidatedTag) => Result export const createTagWorkFlow: WorkFlow = (model) => ok(model).andThen(validateTag).andThen(createTag)

ϫʔΫϑϩʔͷ࢝·ΓͱऴΘΓ͕ɺ֎քͱͷ JOPVU 7BMJEBUFE5BH $SFBUFE5BH 6OWBMJEBUFE5BH 7BMJEBUFE5BH 8PSL'MPX ೖྗͷ%50 ྫ(SBQI2-*OQVU5ZQF Λ 6OWBMJEBUFE5BHʹม׵ UBH3FQPTJUPSZͰ $SFBUFE5BHΛอଘ

(SBQI2-SFTPMWFS3FQPTJUPSZ %# ͱϫʔΫϑϩʔΛ઀ଓ͢Δ import { saveCreatedTag } from '../../../customers/repos/tagRepository' export const createTagMutation = mutationField('createTag', { ... resolve(_root, { input }, context) { const workflow = createTagWorkFlow() // GraphQL 入力をワークフローの入力に変換 const unvalidatedTag = toUnvalidatedTag({ ...input, groupId: context.operator.groupId, }) // ワークフローを実行し Repository パターンの関数で DB に保存 (ここも Result で繋ぐ) const result = ok(unvalidatedTag).andThen(workflow).andThen(saveCreatedTag(context)) return result.match( (tag) => ({ tag: { ...tag, id: toGlobalId('Tag', tag.id), }, }), (error) => { // ここで初めて例外をスロー (単に Nexus にエラーを伝える手段としてスローする) throw error } ) }, })

ok(model).andThen(workflow).andThen(saveCreatedTag(context)) (SBQI2-*OQVU σʔλϕʔε Pure function Model -> Model *0 JOQVUMPBE *0 PVUQVU

ঢ়ଶભҠͷؔ਺ ϥϯλΠϜ΍ϑ ϨʔϜϫʔΫ イベント コマンド

σʔλϑϩʔϓϩάϥϛϯά • 3FTVMUܕͰࣦഊͷ͋ΔܭࢉΛ߹੒͠ɺσʔλͷ௨Γಓͱͯ͠ͷܭࢉաఔΛ࡞Δ – ͦ͜ʹσʔλΛ์ΓࠐΉͱɺͦͷதΛ௨ͬͯঢ়ଶભҠͨ͠σʔλ͕ಘΒΕΔ – σʔλΛσʔλͷ··ɺͦͷՄൖੑΛԼ͛ͣʹѻ͍͍ͨɻ݁Ռ class ͷొ৔ػձ͕ͳ͍ • ܭࢉΛҰຊಓʹ͢Δ – େҬ୤ग़͸͠ͳ͍ɻେҬ୤ग़͢Δͱܭࢉ͕ҰຊಓʹͳΒͳ͍ ˠྫ֎Λ࢖Θͳ͍ – ࣦഊͷ෼ذ͸ 3FTVMUͰ߹੒ ˞3FTVMUܕ͸Ϟφυ – ܭࢉ͕ҰຊಓʹͳΔ σʔλ͸ෆมɻೝ஌ෛՙ͕௿͘ͳΔ

ϑϩϯτΤϯυͱͷൺֱ • ࣌ܥྻʹجͮ͘ঢ়ଶભҠ σʔλϑϩʔ Λએݴతʹهड़͢Δɺͱ͍͏ߟ͑ํ͸ಉ͡ʹͳͬͨ – ܕͱখ͞ͳؔ਺ͷએݴతͳهड़ͰɺϑϩʔΛ૊Έ্͛Δ • ҰํɺϫʔΫϑϩʔͷ࣮૷Λ͍ͯ͠Δͱ͖ͷײ֮ʹ͸·ͩڑ཭͕͋Δ – υϝΠϯΠϕϯτͰঢ়ଶભҠɺͱ͍ͬͯ΋ଟ͘ͷ৔߹͸ʮ7BMJEBUFͯ͠ɺೖྗͰυϝΠϯϞσϧ Λߋ৽͢Δʯ͚ͩ • ݁ՌɺϫʔΫϑϩʔ͸ఆܕతͳهड़͕ଟ͘ͳΔ ŋŋŋ ϑϨʔϜϫʔΫԽͰ͖Δ͔΋ • ϑϩϯτΤϯυ͸ͦ͜Λ 3FBDU΍ &MNͳͲͷϑϨʔϜϫʔΫ͕΍͍ͬͯΔ ͔ͩΒɺΠϕϯτʹର͢ΔϞ σϧͷঢ়ଶભҠͱɺͦͷঢ়ଶΛදݱ͢ΔϓϨθϯςʔγϣϯͷهड़ʹूதͰ͖Δ • ΠϕϯτͱΠϕϯτͷͭͳ͗߹Θͤ ྫ3FTVMUܕʹΑΔ߹੒ Λࣗ෼Ͱهड़͍ͯ͠Δͷ͕ݱঢ়

͕࣌ؒແ͍ͷͰɺ࣮૷ͷৄࡉ͸·ͨޙ೔ • ͜ͷ··Ͱ͸τϥϯβΫγϣϯεΫϦϓτͰɺڽूੑ͕௿͘ͳͬͯ͠·͏ • ΤϯςΟςΟܕͷपลʹɺίΞυϝΠϯϩδοΫͷؔ਺Λ࣮૷ͯ͠Ϟδϡʔϧ෼ׂ͢Δ • ϫʔΫϑϩʔ͸ͦͷίΞυϝΠϯϩδοΫΛ࢖ͬͯϑϩʔΛ૊ΈཱͯΔ໾ׂ͚ͩʹͳΔ – ΫϦʔϯɾΞʔΩςΫνϟͷ 6TF$BTFͱಉ͡

ैདྷख๏ʹൺֱ͠هड़ྔ͸গͳ͍ • σʔλΛσʔλͷ··ӡΜͰ͍ΔͷͰʮ٧Ίସ͑ͯ໾ׂͷҟͳΔผछͷΦϒδΣΫτʯʹ͢ Δŋŋŋͱ͍͏ඞཁ͕ͳ͍ – ஋ͷίϐʔ͸࣮ࡍʹ͸ͱ͜ΖͲ͜Ζ΍͍ͬͯΔ͕ ͨͩͷσʔλΛ ෼ׂ୅ೖͰهड़Ͱ͖ΔͷͰɺ هड़ྔ͸࠷খ

ݱ࣌఺Ͱͷײ૝ • ࢓্༷ͳ͍ঢ়ଶΛ࡞ΒͣʹࡁΉͨΊɺݎ࿚ • ΑΓෳࡶͳϫʔΫϑϩʔΛ࣮૷ͨ͠৔߹΋ಉ͡ߏ଄ʹऩ·Δɻೝ஌ෛՙ͕௿͍ • 3FTVMUܕʹΑΓܭࢉΛܨ͛ΒΕΔΑ͏هड़͢Δྑ͍ڧ੍ྗ͕ಇ͘ – ͨͩ͠ andThen().andThen().asyncAndThen.map() ͸͕͢͞ʹಡΈͮΒ͍ – )BTLFMMͷ EPه๏ɺ'ͷίϯϐϡςʔγϣϯࣜʹ૬౰͢Δ΋ͷ͕ཉ͍͠ŋŋŋ • ஋ͷ٧Ίସ͑ͷهड़͕ͳ͍ͷ͸ ͱͯ΋ خ͍͠

;Γ͔͑Γ https://zenn.dev/mizchi/articles/oop-think-modern

·ͱΊ • ࣌ܥྻʹجͮ͘ঢ়ଶભҠͷએݴͱϑϨʔϜϫʔΫଆʹΑΔঢ়ଶભҠɺௐఀ – ϑϩϯτΤϯυ͸ɺͦͷͨΊͷϑϨʔϜϫʔΫͷ࣮૷͕ॆ࣮͍ͯ͠Δ • ʮએݴతϓϩάϥϛϯάʯͷϓϥΫςΟε͸ɺ೥ݱ࣌఺Ͱ͸ܦݧతʹ΋ྑ͍΋ͷ – όοΫΤϯυ։ൃ΋͜ͷߟ͑ํʹऩᏑ͍ͤͯ͘͞ͷ΋ѱ͘ͳ͍ͷͰ͸ ˠ΍ͬͯΈͨΒ޷ײ৮ – ྲྀߦΔ͔Ͳ͏͔͸Θ͔Γ·ͤΜ • ϑϩϯτΤϯυ όοΫΤϯυͷύϥμΠϜΪϟοϓΛগͳ͍͖͍ͯͨ͘͠

ัଊ • 5ZQF4DSJQUʹ૊ΈࠐΈͷ 3FTVMUܕ͸ͳ͍ͷͰɺOFWFSUISPXΛ࢖ͬͨɻଞʹ΋ GQUTͳͲͷީิ͕͋Δ • 3FTVMUܕ͸ XPSLGMPXͷߏ੒͚ͩͰͳ͋͘ΒΏΔ৔ॴͰ࢖͏ • Ұํʮ3FTVMUܕύζϧʯʹ͸·Δ͕࣌͋Δŋŋŋ • ঺հ࢓੾Εͳ͔͕ͬͨ 1SPNJTF΋ 3FTVMU"TZODʹΑͬͯ 3FTVMUԽͯ͠߹੒Ͱ͖Δ • %PNBJO.PEFMJOH.BEF'VODUJPOBM ʹ͍ͭͯ – ॻ੶ͷఏҊख๏ͦͷ··ͩͱτϥϯβΫγϣϯεΫϦϓτʹͳΓڽूੑ͕௿͘ͳΔɻ ͨͩ͠ *0͸͖ͪΜͱ෼཭͞Ε͍ͯΔͷͰɺΑ Γྑ͍τϥϯβΫγϣϯεΫϦϓτͩͱ͸ࢥ͏ ΤϯςΟςΟͷܕͷपΓʹυϝΠϯϩδοΫͷؔ਺ΛूΊΔ͜ͱͰͦͷ໰୊͸ղফ Ͱ͖͍ͯΔ – ͋ΒΏΔϓϩύςΟʹܕΛఆٛ͢ΔυϝΠϯϓϦϛςΟϒతͳख๏Λ࠾͍ͬͯΔ͕ɺͦ͜͸࠾༻͠ͳ͔ͬͨɻ7BMVF0CKFDUͷΈ /PNJOBMͳܕఆٛΛܕͷϒϥϯυԽ ˞ΦϥΠϦʔͷ 5ZQF4DSJQUຊࢀর ʹΑͬͯߦ͍ͬͯΔ – 3FQPTJUPSZ͸ඞཁͳ͍ͱॻ͔Ε͍͕ͯͨɺू໿Λ͔ͤͬ͘ߏ੒͍ͯ͠ΔͷͰैདྷ௨Γ 3FQPTJUPSZύλʔϯͰू໿୯ҐͰͷӬଓԽ Λߦ͍ͬͯΔɻͳ͓ɺ3FQPTJUPSZͷத਎͸ 1SJTNBΛ࢖͍ͬͯΔ • UZQFͱ JOUFSGBDFͷ࢖͍෼͚ ŋŋŋ GQUTʹ฿͍ͬͯΔɻಛʹͦ͏͠ͳ͚Ε͹ͳΒ͍ཧ༝͸ͳ͍ͱࢥ͏ • ؔ਺͕σϑΥϧτͰΧϦʔԽ͞Εͳ͍ͷ͸࢓ํ͕ͳ͍ɻ࣌ંΧϦʔԽͨ͠ͷΛ๨Εͯ͸·Δ • SFBEPOMZ͸ԣணͯ͠ɺ࢖ͬͯͳ͍ɻ ͪΌΜͱݕ౼͍ͯ͠ͳ͍

ࢀߟจݙ • 4DPUU8MBTDIJO ʮ%PNBJO.PEFMJOH.BEF'VODUJPOBMᴷ5BDLMF4PGUXBSF$PNQMFYJUZXJUI%PNBJO%SJWFO %FTJHOBOE'ʯ • +FSFNZ'BJSCBOL ஶ ϠΪͷ͘͞ΒͪΌΜ ຋༁ ʮϓϩάϥϛϯά&MNᴷ҆શͰϝϯςφϯε͠΍͍͢ϑϩϯτΤϯυ ΞϓϦέʔγϣϯ։ൃೖ໳ʯ • ླ໦ ྅ଠ ʮϓϩΛ໨ࢦ͢ਓͷͨΊͷ5ZQF4DSJQUೖ໳ ᴷ ҆શͳίʔυͷॻ͖ํ͔Βߴ౓ͳܕͷ࢖͍ํ·Ͱʯ • #PSJT$IFSOZ ஶ ࠓଜ ݠ࢜ ؂म ݪ ོจ ຋༁ ʮϓϩάϥϛϯά5ZQF4DSJQUʕεέʔϧ͢Δ+BWB4DSJQUΞϓϦέʔ γϣϯ։ൃʯ • ௚ੵܕͱ௚࿨ܕʹ͍ͭͯ – ʮू߹ͱͯ͠ͷܕ u"O*OUSPEVDUJPOUP&MNʯ IUUQTHVJEFFMNMBOHKQBQQFOEJYUZQFT@BT@TFUTIUNM – ʮͳͥ࣍ʹֶͿݴޠ͸ؔ਺ܕͰ͋Δ΂͖͔ʯ IUUQTZNPUPOHQPPIBUFOBCMPHDPNFOUSZ