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5ZQF4DSJQUͰ5ZQF.BUDIత
ͳ͜ͱΛ͢Δ
͑͢ͳΈνϟϯεॵؾ͍
!LZP@BHP
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݁
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TFBMFEDMBTT PSUSBJU
Λ͍·͠ΐ͏
4DBMBͷ
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ຊ
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͜ΕԿʁ
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5ZQF4DSJQUͷ4USJOH-JUFSBM5ZQFTΛͬͨ
ঢ়ଶͷཧ$IBUXPSL$SFBUPST/PUF
ͷվม൛Ͱ͢ɻ
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ԿΛղܾ͍ͨ͠ͷ͔
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ෳࡶͳঢ়ଶɺ݅ذΛ༰
қʹѻ͑ΔΑ͏ʹ͍ͨ͠
ʢෳࡶͳঢ়ଶɿCPPMFBOͭͱ͔Ͱཧͯ͠ΔΑ͏ͳͷʣ
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۩ମతʹ
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// ਏ͍ྫ
class Message {
constructor(
private sending: boolean,
private editing: boolean,
private deleted: boolean,
) {}
canEdit(): boolean {
if (
!this.sending &&
!this.deleted
) {
return false;
}
return true;
}
}
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͞Βʹ
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// ͬͱਏ͍ྫ
class Message {
constructor(
private sending: boolean,
private loading: boolean, // New!
private editing: boolean,
private deleted: boolean,
) {}
canEdit(): boolean {
if (
!this.sending &&
!this.loading && // New!
!this.deleted
) {
return false;
}
return true;
}
}
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Կ͕ͳͷ͔
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w ঢ়ଶͷΈ߹Θ͕ͤ݅ذΛΈͳ͍ͱஅͰ͖ͳ͍
w ݅ذͷJG͕ෳࡶ
w ม͕Ճ͞Εͨ߹ͷཏੑͷอূ͕͍͠
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// ਏ͍ྫ
class Message {
constructor(
private sending: boolean,
private loading: boolean, // New!
private editing: boolean,
private deleted: boolean,
) {}
canEdit(): boolean {
if (
!this.sending &&
!this.loading && // New!
!this.deleted
) {
return false;
}
return true;
}
}
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DMBTTNFUIPEͰ݅ذΛߦ͏ͱɺʮಛఆͷঢ়
گԼͰDMBTT͕Ͳ͏͍͏ঢ়ଶʹͳΔ͔ʁʯͷஅ͕͘͠
ͳΔɻ
݅ذͦͷঢ়ଶʹ໊લΛ͚ͭͳ͍ͨΊɺʮ݅ذ
ʹҰக͢ΔͷͲ͏͍͏ঢ়ଶ͔ʁʯʹର͢Δղऍ͕ᐆດ
ʹͳΔɻ
ʢ͜ͷ߹ɺDBO&EJUʮฤूՄೳͳঢ়ଶʯͰҰக͢Δ
ͱࢥ͏͚Ͳʣ
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// ֎෦͔Βݟͯಉ͡ঢ়ଶ͔ʁ
const message = new Message(/.../);
const getEditableMessage = () => {
return message.canEdit() ? "मਖ਼Ͱ͖ΔΑʂ" : "मਖ਼
Ͱ͖ͳ͍Αʂ";
}
const showEditableIcon = () => {
return message.canEdit();
}
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ྫ͑ɺ৽͘͠ʮJT4FDSFUʯͱ͍͏มΛՃ͠
ͨ߹ɺDBO&EJUʹӨڹ͢ΔͩΖ͏͔ʁ
·ͨɺӨڹ͢Δͱͯ͠ɺDBO&EJUΛݺͼग़͍ͯ͠
Δଆಉ͡ఆͩΖ͏͔ʁ
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Ͳ͏ղܾ͢Δͷ͔
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ঢ়ଶΛDMBTTԽ͢Δ
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// ָͳྫ
type MessageStateLiterals = "sending" | "loading" |
"editing" | "deleted";
class MessageState {
private state: MessageStateLiterals;
constructor(
sending: boolean,
loading: boolean,
editing: boolean,
deleted: boolean,
) {
// ݅ʹԠͯ͡this.stateMessageStateLiteralsͷ͍ͣΕ
͔Λೖ
}
match(matcher: { [key in MessageStateLiterals]: ()
=> R }): R {
return matcher[this.status]();
}
}
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͍ํ
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class Message {
private state: MessageState;
constructor(
private sending: boolean,
private loading: boolean,
private editing: boolean,
private deleted: boolean,
) {
this.state = new MessageState(true, false, false,
false);
}
canEdit(): boolean {
return this.state.match({
"sending": () => false,
"loading": () => false,
"editing": () => true,
"deleted": () => false,
});
}
}
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ར
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ར
w ঢ়ଶͷஅʹؔΘΔϩδοΫ͕ू͞ΕΔ
w ঢ়ଶͷՃ࣌ʹطଘͷ࣮ʹରͯ͠ཏੑΛڧ੍Ͱ͖Δ
w ঢ়ଶʹର໊ͯ͠લ͕ͭ͘
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ϩδοΫ͕ू͞ΕΔ
// ਏ͍ྫ
class HogeEntity {
private state: HogeState;
constructor(
private id: HogeId,
private name: string,
private enable: boolean,
private body: string,
private selected: boolean,
private focused: boolean,
) {}
toHoge() {
// ঢ়ଶͷมߋ͕෦ʹӅṭ͞Ε͓ͯΓɺςετ͕͍͠
}
}
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ϩδοΫ͕ू͞ΕΔ
// ָͳྫ
type MessageStateLiterals = "sending" | "loading" /…/;
class MessageState {
private state: MessageStateLiterals;
constructor(
sending: boolean,
loading: boolean,
editing: boolean,
deleted: boolean,
) {
// ݅ʹԠͯ͡this.stateMessageStateLiteralsͷ͍ͣΕ͔Λೖ
}
match(matcher: { [key in MessageStateLiterals]: () => R }): R {
return matcher[this.status]();
}
}
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ϩδοΫ͕ू͞ΕΔ
// ָͳྫʢςετʣ
describe(`MessageState`, () => {
const matcher = {
"sending": () => "sending",
// ...
};
[
{
enable: false,
selected: false,
focused: false,
result: "disabled"
},
// શͯͷมͷΈ߹ΘͤΛॻ͘
].forEach(param => {
it(JSON.stringify(param), () => {
let state = new MessageState(param.enable, param.selected,
param.focused);
assert(state.match(matcher) === param.result);
});
});
});
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ঢ়ଶͷՃ࣌ʹطଘͷ࣮ʹରͯ͠
ཏੑΛڧ੍Ͱ͖Δ
// matcherʹશͯͷύλʔϯͷkeyΛίϯύΠϥϨϕϧͰڧ੍
match(matcher: { [key in TypeLiterals]: () => R }): R {
return matcher[this.status]();
}
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ঢ়ଶͷՃ࣌ʹطଘͷ࣮ʹରͯ͠
ཏੑΛڧ੍Ͱ͖Δ
// key͕ෆ͍ͯ͠Δ߹ɺίϯύΠϧ͕௨Βͳ͍ɻ
type MessageStateLiterals = "sending" | "loading" // …;
class MessageState {
// ...
match(matcher: { [key in MessageStateLiterals]: () =>
R }): R {
return matcher[this.status]();
}
}
const state = new MessageState(/.../);
state.match({
"sending": () => true,
// Compile error!
});
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ঢ়ଶʹର໊ͯ͠લ͕ͭ͘
// ਏ͍ྫ
class Message {
constructor(
private sending: boolean,
private editing: boolean,
private deleted: boolean,
) {}
canEdit(): boolean {
// canEditʮฤू͕Մೳʯͱ͍͏݁ՌΛฦ͍ͯ͠Δ͚ͩͰɺ
// ͦͷ࣌ͷMessageͷঢ়ଶද͍ͯ͠ͳ͍ɻ
}
}
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DBO&EJU͓ͦΒ͘ʮฤूՄೳͳঢ়ଶʯͱݴ͍͍ͬͯ
͕ɺࢀর͢Δม͕૿͍͑ͯ͘ͱʮಛఆͷঢ়ଶͱͲ͏
͍͏มͷΈ߹Θͤͳͷ͔ʁʯͷѲ͕͘͠ͳͬͯ
͘Δɻ
ʮಛఆͷ݅ʹର͢ΔมͷΈ߹Θͤʯ͕ෆ໌ͳঢ়ଶ
͕ଓ͘ͱɺͦͷ͏ͪʮݱঢ়ͷมͷΈ߹ΘͤΛಛఆͷ
݅ͱ͢ΔʯΑ͏ʹͳΓɺ࣮͕༷Խ͢Δɻ
ʢ͔͜͠ΕϦϑΝΫλϦϯάʹϦεΫΛ͍ɺ*%&
ͷαϙʔτ͕͋ͬͯਖ਼֬ͳमਖ਼͕ࠔʣ
ࣄલʹঢ়ଶΛΓग़͠ɺ໌֬ͳ໊લΛ͚ͭΔ͜ͱͰ࣮
ͷ༷ԽΛࢭ͠ɺमਖ਼ͷ༨Λ͢͜ͱ͕Ͱ͖Δɻ
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Ͳ͏͍ͬͨ߹ʹ͏
ͷ͔
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Ͳ͏͍ͬͨ߹ʹ͏ͷ͔
w 7BMVF0CKFDUQBUUFSOͷҰ෦ͱͯ͠
w ͦΕͧΕͷ݅ʹ໊ؔͯ͠લ͕ͭ͘
ʢϢϏΩλεݴޠʣ
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ࠜຊతʹղܾ͍ͨ͠
Կ͔ʁ
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ղܾ͍ͨ͠
w ਖ਼͘͠ྨ͢Δ
w ਖ਼໋໊͘͢͠Δ
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ʮ݅ذͷ݁Ռͱͯ͠ͷྨʯͰͳ͘ɺ༗ݶݸͷ
ྨͷҰͭͱͯ͠ॴଐΛׂΓͯΔɻ
ʮૹ৴தϑϥάͱฤूࡁΈϑϥά͕Φϯͷϝοηʔδʯ
Ͱͳ͘ɺʮ্ॻ͖ૹ৴தϝοηʔδʯͱͯ͠ڍಈΛׂ
ΓͯΔɻ
ʮ݅ذͷ݁ՌͷҰ෦ʯͰͳ͘ɺذͷ݁Ռʹର
໊ͯ͠લΛ͚ͭΔɻ
ʮૹ৴ऀ͕ۭͰຊจ͕͋Δ߹݅ذ͢ΔʯͷͰͳ
͘ɺʮૹ৴ऀ͕ۭͰຊจ͕͋Δ߹γεςϜϝοηʔδ
ͱ໋໊ͯ͢͠Δʯ͜ͱͰɺҎޙʮγεςϜϝοηʔ
δʯʹରͯ͠ॲཧΛߦ͏
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࣮ͷ؆ུԽ
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ҎԼͷΑ͏ͳDMBTTΛఆٛ͢Δ͜ͱ
Ͱ࣮Λ؆ུԽͰ͖Δ
type BaseTypeLiterals = { [key in L]: ()
=> R }
abstract class BaseType {
constructor(protected value: TypeLiterals) {}
getValue(): TypeLiterals {
return this.value;
}
equals(type: TypeLiterals): boolean {
return this.getValue() === type;
}
equalType(target: T): boolean {
return this.getValue() === target.getValue();
}
match(matcher: BaseTypeLiterals): R {
return matcher[this.getValue()]();
}
}
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ҎԼͷΑ͏ͳDMBTTΛఆٛ͢Δ͜ͱ
Ͱ࣮Λ؆ུԽͰ͖Δ
class MessageState extends BaseType<"sending" | /.../
> {
constructor(
sending: boolean,
loading: boolean,
/.../
) {
if (sending) {
return super("sending");
}
// ඞཁͳذΛՃ
}
}
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2"
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2"
w 2ɿ༷ύλʔϯʢ4QFDJpDBUJPOύλʔϯʣͰʁ
w "ɿ:FTɻͨͩɺ5ZQF4DSJQUͰTFBMFEम০ࢠΛ࠶ݱͰ͖ͨͷίʔυΛॻ্͘Ͱศ
རͩͬͨ
ʢ4DBMBͬͯΔਓʹͨΓલͰʣ
w 2ɿ+BWBͷ&OVNͰʁ
w "ɿ+BWBͷ&OVNͰTXJDIͷཏੑΛڧ੍Ͱ͖ͳ͍ͷͰेͰͳ͍ͱ͍͏ཧղ
ʢͪͳΈʹ5ZQF4DSJQUͷFOVNશ͘ʹཱͨͳ͍ͱ͍͏ͷਃ͠ఴ͓͖͑ͯ·͢ʣ
w 2ɿ4XJGUͷ&OVNͰʁ
w "ɿ:FTɻ<4XJGU8BTNDPNQJMF4XJGUUP8FC"TTFNCMZ> IUUQT
TXJGUXBTNPSH
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͓ΘΓ