Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Speaker Deck
PRO
Sign in
Sign up for free
TypeScript and Immutability
Taketoshi Aono(青野健利 a.k.a brn)
September 18, 2018
Programming
2
1.4k
TypeScript and Immutability
TypeScriptでImmutableなエンティティを表現する方法あれこれ
Taketoshi Aono(青野健利 a.k.a brn)
September 18, 2018
Tweet
Share
More Decks by Taketoshi Aono(青野健利 a.k.a brn)
See All by Taketoshi Aono(青野健利 a.k.a brn)
CA 1Day Youth Bootcamp for Frontend LT
brn
0
360
Modern TypeScript
brn
2
570
javascript - behind the scene
brn
3
500
tc39 proposals
brn
0
520
プロダクト開発とTypeScript
brn
8
2.5k
React-Springでリッチなアニメーション
brn
1
440
javascript internationalization API
brn
0
550
How V8 executes WASM
brn
3
1.4k
memory_in_javascript.pdf
brn
0
710
Other Decks in Programming
See All in Programming
Amebaブログの会員画面システム刷新の道程
ryotasugawara
1
240
CDKでValidationする本当の方法 / cdk-validation
gotok365
1
210
データドリブンな組織の不正検知
fkubota
0
260
OSC大阪 パスワード認証は人類には早すぎる ~ IDaaSを使ったソーシャルログインのすすめ ~
authyasan
7
1.5k
10年以上続くプロダクトの フロントエンド刷新プロジェクトのふりかえり
yotahada3
2
340
tidy_rpart
bk_18
0
600
ECS Service Connectでマイクロサービスを繋いでみた
xblood
0
550
Glance App Widgetでウィジェットを作ろう / MoT TechTalk #15
mot_techtalk
0
120
子育てとEMと転職と
_atsushisakai
1
410
ペパカレで入社した私が感じた2つのギャップと向き合い方
kosuke_ito
0
280
Swift Concurrency in GoodNotes
inamiy
4
1.3k
OSSから学んだPR Descriptionの書き方
fugakkbn
4
130
Featured
See All Featured
Templates, Plugins, & Blocks: Oh My! Creating the theme that thinks of everything
marktimemedia
15
1.2k
Building Adaptive Systems
keathley
27
1.3k
CSS Pre-Processors: Stylus, Less & Sass
bermonpainter
349
27k
I Don’t Have Time: Getting Over the Fear to Launch Your Podcast
jcasabona
13
1.1k
Responsive Adventures: Dirty Tricks From The Dark Corners of Front-End
smashingmag
239
19k
Clear Off the Table
cherdarchuk
79
290k
Raft: Consensus for Rubyists
vanstee
130
5.7k
Atom: Resistance is Futile
akmur
256
24k
The Pragmatic Product Professional
lauravandoore
21
3.4k
Designing with Data
zakiwarfel
91
4.2k
How to name files
jennybc
47
73k
The Language of Interfaces
destraynor
149
21k
Transcript
TypeScript & Immutability
Name @brn (ꫬꅿ⨳ⵃ) Occupation ؿٗٝزؒٝسؒٝآص،٥ط؎ذ؍ـؒٝآص، Company Cyberagent ،سذؙأةآؔ AI Messenger
OSS Contributor of V8 About http://info.b6n.ch
What is Immutability?
Immutablityהכ㢌刿♶〳腉䚍ךֿה TypeScript(javascript)דכ㛇劤涸חכׅץג㢌刿〳腉(Mutable) 㹋植ׅחכ㢩鿇ךٓ؎ـٓٔך⸂⦵ַծأفٖحس 怴皾㶨⢪ְתֻ׃ַזְ What is Immutability?
Why Immutability is so important?
ؔـآؙؑزך㢌刿ָ♶〳腉דֿ֮הכفؚٗٓي⟃♴ך銲 挿ד知患חׅ • 撑鷲麓䚍(ꟼ侧ָ⦼㢌刿׃זְ) • ⶰ⡲欽ָ饯ֹזְ ؙٓ؎،ٝز؟؎سךفؚٗٓىؚٝדכ⟃♴ךⵃ挿֮ ֲ • ReactךPureComponentד知⽃ח嫰鯰דֹ
What is Immutability is so important?
Immutability in REAL LIFE
׃ַ׃TypeScript(js)ד㹋植׃״ֲהׅה⟃♴ך㉏겗ָ֮ • ٓ؎ـٓٔ⢪ֲ • IOכוֲׅ(DOMծhttpծStorage) • 㘗דⴻⴽדֹ Immutability in REAL
LIFE
Immtauble.js Immutable.jsכTypeScriptה湱䚍ָ䝤ְ הֻחⰅ㶨ךRecord㘗ד邌植׃״ֲהׅה immutableז㘗הֲדכזְ㘗㹀纏2ꅾד㹀纏ׅ䗳銲ָ֮ Immutability in REAL LIFE
immer immerכPlainObjectImmutableח׃גֻךד⢪ְװְׅ ָծclassָ⢪ִזְךד䮶莸ְׇ㜥さכ Objectחًاحس㹀纏ׅ䕎חז ָծֿכ䧮䢧׃גimmer⢪ֲֿהח׃ Immutability in REAL LIFE
How to treat IO 姻湫10ⴓד鑧׃ֹזְךד㸣穠ח • MVI(Cyclejs괏)ⵃ欽׃גծIO㢩ך⚅歲חꟗׄ鴥 (Driver) • 穠卓ֽActionהⰟח「ֽ《
• reduxד֮לmiddlewareחIOע䫎־ Immutability in REAL LIFE
Model View Intent ًٔحز • ٌشسקו搀椚זֻIOꟗׄ鴥 • asyncחאְג罋ִ䗳銲ָזֻז رًٔحز •
Actionךװהָꬊ䌢ח㟓ִ Immutability in REAL LIFE
How to express immutable type. TypeScriptדImmutability邌植ׅחכ⟃♴ך倯岀ָ֮կ • readonly⢪ֲ • ConstArray٥ConstMap⢪ֲ
Immutability in REAL LIFE
Readonly فٗػذ؍ָ铣《ךד剣ֿה㹑鎉ׅ ׃ؔـآؙؑزך⚥魦כ㢌刿〳腉 Immutability in REAL LIFE
ReadonlyArray٥ReadonlyMap 灶㠨涸ז㢌刿遤ֲꟼ侧ָꤐׁغ٦آّٝך㘗㹀纏 TypeScriptח穈鴥תגְ sort٥reverse٥spliceהַדֹזְ(㘗㹀纏♳) Immutability in REAL LIFE
ֿ穈さׇג邌植ׅ C++ח֮װַגConst㘗הㄏせ׃ ׁחׅץגך㾩䚍《ꤐֻMutable㘗㹀纏ׅ (׃ծConstMapכ⢪זְךד♧傉㹀纏׃זְ) Immutability in REAL LIFE
type Primitive = undefined | null | boolean | string
| number | Function;! ! interface ConstArray<T> extends ReadonlyArray<Const<T>> {}! type ConstObject<T> = {! readonly [P in keyof T]: Const<T[P]>! };! ! type Const<T> = T extends Primitive! ? T! : T extends ConstArray<any>! ? T! : T extends (infer R)[]! ? ConstArray<R>! : T extends object ? ConstObject<T> : T;!
type Mutable<T> = T extends Primitive! ? T! : T
extends MutableArray<any>! ? T! : T extends (infer R)[]! ? MutableArray<R>! : T extends ConstArray<infer A>! ? MutableArray<A>! : T extends object ? MutableObject<T> : T;! ! interface MutableArray<T> extends Array<Mutable<T>> {}! ! type MutableObject<T> = {! -readonly [P in keyof T]: Mutable<T[P]>! };!
ֿדطأز׃ⰋגךؔـآؙؑزImmutableחדֹ ծOptionalהַPromiseהַָ窃ה⦜זֿהחז (ConditionalTypeך勴⟝ָוו㟓ִ) Immutability in REAL LIFE
Writable/Writer 荈⡲ךؒٝذ؍ذ؍דReadOnlyXXXְזךװְ ؒٝذ؍ذ؍㹀纏ׅהֹחفٗػذ؍ךךؔـآؙؑزה 刿倜ך遤ֲWriterחⴓꨄ׃ג㹀纏ׅ Writableכ朐䡾ך㝄 Writerכ朐䡾䭯׆ծ刿倜ׅך乼⡲ךָ㹀纏ׁגְ Immutability in REAL
LIFE
interface HumanEntityWriter extends Writer<HumanEntity> {! updateName(name: string): void;! updateAge(age: number):
void;! }! ! interface HumanEntity extends Writable<HumanEntityWriter> {! name: string;! age: number;! }!
interface Writer<T> {! _target: T;! }! interface Writable<T extends Writer<U>,
U> {! _writer: T;! }!
mutate WritableַWriter《⳿׃ծMutableח㢌䳔ׅկ Immutability in REAL LIFE
const next = mutate(humanEntity, writer => {! writer.updateName('Roppongi.js');! writer.updateAge(6);! })!
import produce from 'immer';! function mutate<T extends Writable<U>, U>(! entity:
T, ! callback: (writer: U) => void! ) {! produce(entity, draft => {! callback({! ...entity._writer,! _target: entity! });! });! }!
Benefit ReadהWriteⴓֽג㹀纏ֿׅהד搀꼽ז✲佦ָ幾 תծWriterךًاحس⟃㢩ד⦼㢌刿ֿׅהכדֹזְךד (㘗٥暟椚ך⚕ד)㸜Ⰻ Componentך⚥ד⦼剅ֹ䳔ִדֹזְ Immutability in REAL LIFE
Complicated types… 㹋ꥷחכmutateꟼ侧ך㹀纏כה醱꧟ד ConstהMutableך㢌䳔㹀纏ָⰅגְׅ Immutability in REAL LIFE
Problems immerָؕأةيؙٓأ「ֽ➰ֽזְֶַ־ד entityワָ׳הES5괏חזג • class⢪זְ • 竰䪫כأفٖحس怴皾㶨 • فٓ؎ك٦زفٗػذ؍כ،ٝت٦أ؝، Immutability
in REAL LIFE
Summary ׳ה㉏겗כֽ֮ו筨ׄגװװֻׅזկ Immutable.jsד气䒦׃גְךד⡭鎘״ַ Plain Object剑넝 Immutability in REAL LIFE