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TypeScript による GraphQL バックエンド開発

Naoya Ito
October 14, 2022

TypeScript による GraphQL バックエンド開発

10/14 の Tech Play での発表資料です
https://techplay.jp/event/873259

Naoya Ito

October 14, 2022
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  1. ࡢࠓɺϑϩϯτΤϯυ όοΫΤϯυͷٕज़తؔ৺ࣄʹΪϟοϓ • ΞϓϦέʔγϣϯͷঢ়ଶ؅ཧϞσϧ • σβΠϯγεςϜ • ϓϦϨϯμϦϯά • ŋŋŋ

    ϑϩϯτΤϯυ όοΫΤϯυ • υϝΠϯϞσϧ • ϨΠϠʔυɾΞʔΩςΫνϟ • $234 • ŋŋŋ ૊৫ͷٕज़࿅౓্͕͕Ε͹্͕Δ΄Ͳɺؔ৺ࣄͷΪϟοϓ͕޿͕͍ͬͯͬͨ
  2. 3FBDUͰϑϩϯτΤϯυΛ։ൃ͔ͯ͠Βɺ όοΫΤϯυΛॻ͘ͱŋŋŋ • 3FBDUŋŋŋ খ͞ͳؔ਺Λ૊Έ߹Θͤͯએݴతʹॻ͍͍ͯ͘ • όοΫΤϯυ ŋŋŋ ΫϥεΛͨ͘͞Μॻ͍ͯɺϨΠϠʔΛލ͙ͱ %50Ͱͷ஋٧Ίସ͑Λߦͬ

    ͯɺJOUFSGBDFͰґଘੑͷٯసΛߦͬͯŋŋŋ – ʮŋŋŋϑϩϯτΤϯυͩͱ͜͏͍͏͜ͱɺ͋Μ·Γ΍Βͳ͍ΑͶʯ ։ൃ࣌ͷϝϯλϧϞσϧͷΪϟοϓ͕େ͖͍ ίϯςΩετεΠονͷෛ୲΋େ͖͍
  3. (SBQI2-2VFSZͱυϝΠϯϞσϧͷʮू໿ʯ͸ɺטΈ߹Θ͕ͤѱ͍ • (SBQI2-2VFSZ ˞ .VUBUJPOͰ͸ͳ͍ – ΫϥΠΞϯτ͕ϢʔεέʔεΛߏ੒͢Δ – ू໿୯ҐͰ͸ͳ͘ɺϦιʔε୯ҐͰૢ࡞͞ΕΔ •

    (SBQI2-2VFSZʹݶΒͣ ू໿Λશ෦Ҿ͘Θ͚ʹ͍͔ͳ͍৔໘ͰͲ͏͢Δ͔ŋŋŋ͸ '"2 – ྫݕࡧҰཡϖʔδ – $234Λద༻ͯ͠ 2VFSZ4FSWJDFΛ࣮૷͢Δͱ͍͏ͷ͕ɺͻͱͭͷղܾࡦ
  4. Domain Model GraphQL Mutation Repository ߋ৽ܥ GraphQL Query Prisma Prisma

    ࣌ʑ ബ͍ %PNBJO૚ ࢀরܥ (SBQI2-1SJTNB$234
  5. 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
  6. ͨͱ͑͹ʮ॓ധ༧໿ʯΛྫʹυϝΠϯϞσϧΛվΊͯߟ͑ͯΈΔ • ͲΜͳ؍఺ʹ஫໨ͯ͠ߟ͑ͯΈΔ΂͖͔ – σʔλߏ଄ – &3ਤ – Ϋϥεͷ࣮૷ –

    ը໘ • ͍ͣΕ΋੩తͳߏ଄ʹয఺Λ౰͍ͯͯΔɻࢹ఺Λม͑ͯΈ͍ͨ – ಈతͳ΋ͷŋŋŋυϝΠϯΠϕϯτ΍ঢ়ଶʹয఺Λ౰ͯͯΈΔͱ
  7. model -> model model -> model event &WFOU)BOEMFS 8FC"QQͳΒ SPVUFS

    %#ʹอଘ͠ Ϩεϙϯε 6* event event ֎ͷੈք ֎ͷੈք ֎ͷੈք Πϕϯτ ˠϞσϧͷঢ়ଶભҠ 🤔 Ͳ͔͜Ͱݟͨͳŋŋŋ
  8. 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 }
  9. 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
  10. 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
  11. 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
  12. ͪ͜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 }
  13. 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
  14. 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 ؔ਺ 
  15. 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 %*͢Δɻޙड़
  16. 3FTVMUܕͰࣦഊͷՄೳੑͷ͋ΔܭࢉΛҰຊಓʹ߹੒͢Δ import { Result, ok, err } from 'neverthrow' function

    itsUnder100(n: number): Result<number, Error> { return n <= 100 ? ok(n) : err(new Error('100より大きい数字です')) } function itsEven(n: number): Result<number, Error> { return n % 2 == 0 ? ok(n) : err(new Error('奇数です')) } function itsPositive(n: number): Result<number, Error> { 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 } )
  17. type validateTag = (model: UnvalidatedTag) => Result<ValidatedTag, ValidationError> 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
  18. 3FTVMUܕͰঢ়ଶભҠؔ਺Λܨ͛ͯɺϫʔΫϑϩʔ υϝΠϯϩδοΫ Λ࡞Δ type WorkFlow = (model: UnvalidatedTag) => Result<CreatedTag,

    CreateTagError> export const createTagWorkFlow: WorkFlow = (model) => ok(model).andThen(validateTag).andThen(createTag)
  19. (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 } ) }, })
  20. 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
  21. υϝΠϯϞσϧͷอଘ͸ैདྷ௨Γ 3FQPTJUPSZ export const saveCraetedTag = ({ prisma }: applicationContext)

    => (model: CreatedTag): ResultAsync<TagData, PrismaClientError> => { const { kind: _, ...tag } = model const icon = toIconData(tag.icon) return ResultAsync.fromPromise( prisma.tag.create({ data: { ...tag, ...icon, }, }), PrismaClientError ) } 3FTVMU"TZODGSPN1SPNJTFΛ࢖͏͜ ͱͰ 1SPNJTFΛ 3FTVMUʹแΈɺଞͷ 3FTVMUܕͱ߹੒Ͱ͖Δ ྫ֎΋෧͡ࠐΊΔ͜ͱ͕Ͱ͖Δ
  22. 3FQPTJUPSZύλʔϯʹ͍ͭͯ • %PNBJO.PEFM.BEF'VODUJPOBMͰ͸ʮ͜ͷख๏ͳΒ 3FQPTJUPSZ͸ඞཁͳ͍ʯͱ͍͏هड़͕͋Δ – ᐌ͘ 3FQPTJUPSZ͸ .VUBCMFͳυϝΠϯϞσϧʹجͮ͘΋ͷ͔ͩΒɺͱͷ͜ͱ – ղઆ͕୹͍͜ͱ΋͋Γจҙ͕Α͘௫Ίͳ͔ͬͨŋŋŋ

    • ैདྷ௨Γ 3FQPTJUPSZΛར༻ – ͨͩ͠3FQPTJUPSZΫϥεͷΦϒδΣΫτͰ͸ͳ͘ɺؔ਺ – ू໿͸ηΦϦʔ௨Γʹߏங͍ͯ͠Δɻ׶͑ͯݸผͷߋ৽༻ؔ਺ʹ෼ׂ͢Δඞཁ͸ͳ͍ͱߟ͑ͨ
  23. ΤϯςΟςΟͷܕΛج఺ʹͨ͠ϞδϡʔϧΛ࡞ΓɺίΞυϝΠϯϩδοΫؔ਺͸ͦ͜ʹूΊΔ // customers/objects/tag.ts export interface Tag { id: TagId groupId:

    RestaurantGroupId label: TagLabel icon: TagIcon sortOrder: number builtin: boolean } export const updateLabel = (label: TagLabel) => (tag: Tag) => ({ ...tag, label }) export const updateIcon = (icon: TagIcon) => (tag: Tag) => ({ ...tag, icon })
  24. (SBQI2- %# 3FQPTJUPSZ *OQVU 5BH 6OWBMJEBUFE $PNNBOE 7BMJEBUFE $PNNBOE ŋŋŋ

    6QEBUFE5BH 8PSL'MPX HFU5BH#Z*E ೖྗͱυϝΠϯΦϒδΣΫτΛͻͱͭʹ·ͱΊͨʮίϚϯυʯΛϫʔΫϑϩʔͷೖྗʹ͢Δ ͦͷ্Ͱɺઌ΄Ͳಉ༷ɺ୯ํ޲σʔλ ϑϩʔͷதͰঢ়ଶભҠͤͯ͞໨తͷग़ ྗʹ͚͍ۙͮͯ͘
  25. // customers/workflows/updateTag.ts interface UnvalidatedInput { kind: 'Unvalidated' label: string icon?:

    { symbol: string; type: TagIconType; color?: string | null | undefined } | null | undefined } interface UnvalidatedCommand { input: UnvalidatedInput tag: Tag } interface ValidatedInput { kind: 'Validated' label: TagLabel icon: TagIcon } interface ValidatedCommand { input: ValidatedInput tag: Tag } // Output type UpdatedTag = Tag & { kind: 'Updated' }
  26. // customers/workflows/updateTag.ts // substep1: validateCommand type validateCommand = (command: UnvalidatedCommand)

    => Result<ValidatedCommand, ValidationError> // substep2: updateTag type updateTag = (command: ValidatedCommand) => Result<UpdatedTag, UpdateTagError> // workflow: validateCommand -> updateTag type WorkFlow = (command: UnvalidatedCommand) => Result<UpdatedTag, UpdateTagError> export const updateTagWorkFlow = (): WorkFlow => (command) => ok(command).andThen(validateCommand).andThen(updateTag)
  27. // customers/repos/tagRepository.ts export const findTagById = ({ prisma }: applicationContext)

    => (id: TagId): ResultAsync<Tag | null, ValidationError | PrismaClientError> => ResultAsync.fromPromise( prisma.tag.findUnique({ where: { id } }), PrismaClientError ).andThen((tag) => (tag ? Tag(tag) : ok(null))) export const getTagById = (context: applicationContext) => (id: TagId): ResultAsync<Tag, EntityNotFound | ValidationError | PrismaClientError> => findTagById(context)(id).andThen((tag) => tag ? ok(tag) : err(new EntityNotFound(`タグがみつかりません: ${id}`)) )
  28. // graphql/mutation/updateTag.ts export const updateTagMutation = mutationField('updateTag', { type: UpdateTagPayload,

    args: { tagId: idArg({ description: 'タグID' }), input: TagInput, }, resolve(_root, { tagId, input }, context) { const workflow = updateTagWorkFlow() const preprocess = TagId(tagId) .asyncAndThen(getTagById(context)) .map((tag) => toUnvalidatedCommand({ input, tag })) const result = preprocess.andThen(workflow).andThen(saveTag(context)) return result.match( ... ) }, })
  29. %FQFOEFODZ*OKFDUJPOΛ࢖͏ • *0ͦͷ΋ͷΛۀ຿ॲཧͷ్த͔ΒऔΓআ͚ͳ͍ͳΒɺ%*Ͱ XPSLGMPX͕ *0 ʹ·ͭΘΔܕ ྫ σʔλ ϕʔε઀ଓΦϒδΣΫτ ʹґଘ͠ͳ͍Α͏ʹ͢Δ

    – XPSLGMPX͸ *0ʹґଘ͠ͳ͍ؔ਺Ͱ͋Δ͜ͱΛҡ࣋͢Δ • %*͸ΧϦʔԽʹΑΔ෦෼ద༻Ͱ࣮ݱ͢Δ – %PNBJO.PEFM .BEF'VODUJPOBMͰఏҊ͞Ε͍ͯͨख๏
  30. // customer/services/tag.ts export type getTagSortOrder = ({ groupId }: {

    groupId: RestaurantGroupId }) => ResultAsync<number, PrismaClientError> export const getTagSortOrder = ({ prisma }: applicationContext): getTagSortOrder => ({ groupId }) => ResultAsync.fromPromise( prisma.tag .aggregate({ _max: { sortOrder: true, }, where: { groupId }, }) .then((x) => (x._max.sortOrder ? x._max.sortOrder + 1 : 1)), PrismaClientError ) ΧϦʔԽʹΑΓɺ෦෼ద༻Ͱ͖ΔΑ͏ ʹ͢Δ
  31. // graphql/mutation/createTag.ts export const createTagMutation = mutationField('createTag', { type: CreateTagPayload,

    args: { input: TagInput, }, resolve(_root, { input }, context) { const workflow = createTagWorkFlow(checkTagExists(context), getTagSortOrder(context)) // DI const unvalidatedTag = toUnvalidatedTag({ ...input, groupId: context.operator.groupId, }) const result = workflow(unvalidatedTag).andThen(saveCreatedTag(context)) return result.match(...) }, }) ϫʔΫϑϩʔʹ͸ίϯςΩετ ͕෦෼ద༻͞Εͨؔ਺Λ౉͢
  32. // customer/workflows/createTag.ts type createTag = (model: ValidatedTag) => ResultAsync<CreatedTag, CreateTagError>

    const createTag = (getTagSortOrder: getTagSortOrder): createTag => (model) => { const values = getTagSortOrder({ groupId: model.groupId }) return values.map((n) => ({ ...model, kind: 'Created', id: generateTagId(), sortOrder: n, builtin: false, })) } // workflow: validateTag -> createTag type WorkFlow = (model: UnvalidatedTag) => ResultAsync<CreatedTag, CreateTagError> export const createTagWorkFlow = ( checkTagExists: checkTagExists, // dependency getTagSortOrder: getTagSortOrder // dependency ): WorkFlow => (model) => okAsync(model).andThen(validateTag(checkTagExists)).andThen(createTag(getTagSortOrder)) ϫʔΫϑϩʔ͔Β͸σʔλϕʔείϯ ςΩετ͕ཁΒͳ͍७ਮؔ਺ʹݟ͑Δɻ ͭ·Γɺςετ΍σόοά࣌ɺ७ਮؔ ਺ʹࠩ͠׵͑Δ͜ͱ΋Ͱ͖Δ %*͞Εͨؔ਺Λ஫ೖͭͭ͠΋ɺσʔλ ϑϩʔ͸͜Ε·Ͱ௨Γͷߏ଄ HFU5BH4PSU0SEFS΋ 3FTVMUΛฦ͢ ͷͰɺσʔλϑϩʔͷதͰ݁Ռ͸߹੒ ͞ΕΔ
  33. 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
  34. ैདྷͷΞʔΩςΫνϟͱͷࠩҟʹ͍ͭͯ • ్தͰ৮Εͨͱ͓Γɺେ࿮ͷΞʔΩςΫνϟ͸͋·ΓมΘ͍ͬͯͳ͍ – 6TF$BTF૬౰ͷ XPSLGMPX – 3FQPTJUPSZ – ίΞυϝΠϯϞσϧ

    – ू໿ɺΤϯςΟςΟ • ίϯϙʔωϯτͷதͷ࣮૷ͷύϥμΠϜ͕ҟͳΔ – ܕͰۀ຿ͷঢ়ଶɺϑϩʔΛએݴ͢Δ – σʔλϑϩʔϓϩάϥϛϯάʹΑΔɺ୯ํߴσʔλϑϩʔ
  35. ݱ࣌఺Ͱͷײ૝ • ࢓্༷ͳ͍ঢ়ଶΛ࡞ΒͣʹࡁΉͨΊɺݎ࿚ • ΑΓෳࡶͳϫʔΫϑϩʔΛ࣮૷ͨ͠৔߹΋ಉ͡ߏ଄ʹऩ·Δɻೝ஌ෛՙ͕௿͍ • 3FTVMUܕʹΑΓܭࢉΛܨ͛ΒΕΔΑ͏هड़͢Δྑ͍ڧ੍ྗ͕ಇ͘ – ͨͩ͠ andThen().andThen().asyncAndThen().map()

    ͸͕͢͞ʹಡΈͮΒ͍ – 3FTVMU͕ೖΕࢠʹͳͬͯ͘Δͱɺ3FTVMUܕύζϧʹ೰Ή࣌΋ŋŋŋ • )BTLFMMͷ EPه๏ɺ'ͷίϯϐϡςʔγϣϯࣜʹ૬౰͢Δ΋ͷ͕ཉ͍͠ŋŋŋ • ஋ͷ٧Ίସ͑ͷهड़͕ͳ͍ͷ͸ ͱͯ΋ خ͍͠
  36. ·ͱΊ • ࣌ܥྻʹجͮ͘ঢ়ଶભҠͷએݴͱϑϨʔϜϫʔΫଆʹΑΔঢ়ଶભҠɺௐఀ – ϑϩϯτΤϯυ͸ɺͦͷͨΊͷϑϨʔϜϫʔΫͷ࣮૷͕ॆ࣮͍ͯ͠Δ – ؔ਺ܕ͔ΒӨڹΛड͚ͨྑ͍࡞๏ • ʮએݴతϓϩάϥϛϯάʯͷϓϥΫςΟε͸ɺ೥ݱ࣌఺Ͱ͸ܦݧతʹ΋ྑ͍΋ͷ –

    όοΫΤϯυ։ൃ΋͜ͷߟ͑ํʹऩᏑ͍ͤͯ͘͞ͷ΋ѱ͘ͳ͍ͷͰ͸ ˠ΍ͬͯΈͨΒ޷ײ৮ – ྲྀߦΔ͔Ͳ͏͔͸Θ͔Γ·ͤΜ • ϑϩϯτΤϯυ όοΫΤϯυͷύϥμΠϜΪϟοϓΛগͳ͍͖͍ͯͨ͘͠
  37. ัଊ • 5ZQF4DSJQUʹ૊ΈࠐΈͷ 3FTVMUܕ͸ͳ͍ͷͰɺOFWFSUISPXΛ࢖ͬͨɻଞʹ΋ GQUTͳͲͷީิ͕͋Δ • 3FTVMUܕ͸ XPSLGMPXͷߏ੒͚ͩͰͳ͋͘ΒΏΔ৔ॴͰ࢖͏ • 1SPNJTF΋

    3FTVMU"TZODʹΑͬͯ 3FTVMUԽͯ͠߹੒Ͱ͖Δ • UZQFͱ JOUFSGBDFͷ࢖͍෼͚ ŋŋŋ GQUTʹ฿͍ͬͯΔɻಛʹͦ͏͠ͳ͚Ε͹ͳΒ͍ཧ༝͸ͳ͍ͱࢥ͏ • ؔ਺͕σϑΥϧτͰΧϦʔԽ͞Εͳ͍ͷ͸࢓ํ͕ͳ͍ɻ࣌ંΧϦʔԽͨ͠ͷΛ๨Εͯ͸·Δ • SFBEPOMZ͸ԣணͯ͠ɺ࢖ͬͯͳ͍ɻ ͪΌΜͱݕ౼͍ͯ͠ͳ͍
  38. ͓·͚ ŋŋŋ OFXUZQF ׬શίϯετϥΫλ declare const __newtype: unique symbol export

    type newtype<Constructor, Type> = Type & { readonly [__newtype]: Constructor } export type TagId = newtype<'TagId', string> export function TagId(value: string): Result<TagId, ValidationError> { return validate(value) ? ok(value as TagId) : err(new ValidationError('IDの形式が不正です')) } υϝΠϯϞσϧͷߏ੒ʹ /PNJOBMͳܕ͕ཉ͍͠ͱ͖͸ɺ͜͏͍ ͏࣮૷Ͱ΍ͬͯ·͢
  39. 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