ジェネレータを有効活用し隊 / Kyoto.js 11 LT

Kyoto.js 11 http://kyotojs.connpass.com/event/39462/

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1. δΣω Ϩ ʔ λ Λ ༗ ޮ ׆ ༻ ͠ ୂ 2 0 1 6 - 1 0 - 2 2 K y o t o . j s 1 1 Twitter @susisu2413 / GitHub @susisu
2. Q . δΣω Ϩ ʔ λ ͸ Կ ʹ ࢖ ͑Δʁ
3. 1 . ί ϧ ʔ νϯ
4. app.use(function* (next) { const start = new Date(); // (1) yield next; const end = new Date(); // (3) // log (4) }); ! app.use(function* (next) { yield next; // respond (2)
 }); ྫ: Koa
5. 2 . ஗ Ԇ Ϧε τ
6. function range(a, b, s = 1) { const arr = []; for (let n = a; n < b; n += s) { arr.push(n); } return arr; } ! for (const n of range(1, 10)) { doSomething(n); // from 1 to 9 }
7. function* xrange(a, b, s = 1) { for (let n = a; n < b; n += s) { yield n; } } ! for (const n of xrange(1, 10)) { doSomething(n); // from 1 to 9 }
8. function* fibonacci() { let [a, b] = [1, 1]; while (true) { yield a; [a, b] = [b, a + b]; } } ! for (const n of fibonacci()) { doSomething(n); // 1, 1, 2, 3, 5, ... }
9. 3 . Π ς Ϩ ʔ λ ͷ Ճ ޻
10. function* concat(iter1, iter2) { yield* iter1; yield* iter2; } ! for (const x of concat(arr1, arr2)) { doSomething(x); }
11. function* map(func, iter) { for (const x of iter) { yield func(x); } } ! for (const n of map(n => n ** 2, arr)) { doSomething(n); }
12. 4 . ඇ ಉ ظ ॲ ཧ
13. fetch().then(x => fetch().then(y => fetch().then(z => doSomething(x, y, z) ) ) ); before (Promise)
14. co(function* () { const x = yield fetch(); const y = yield fetch(); const z = yield fetch(); return doSomething(x, y, z); }); after (Promise + Generator + co)
15. Q . ଞ ʹ ΋ δΣω Ϩ ʔ λ ͕ ࢖ ͑Δ ৔ ໘ ͸ ͋ Δʁ
16. ͦ ΋ ͦ ΋ δΣω Ϩ ʔ λ ͱ ͸
17. g e n . n e x t ( )
18. { d o n e : f a l s e , v a l u e : * } g e n . n e x t ( )
19. { d o n e : f a l s e , v a l u e : * } g e n . n e x t ( ) g e n . n e x t ( ) gen.next ͷத਎΋มΘ͍ͬͯΔ
20. { d o n e : f a l s e , v a l u e : * } { d o n e : f a l s e , v a l u e : * } g e n . n e x t ( ) g e n . n e x t ( ) g e n . n e x t ( )
21. { d o n e : f a l s e , v a l u e : * } { d o n e : f a l s e , v a l u e : * } { d o n e : t r u e , v a l u e : * } g e n . n e x t ( ) g e n . n e x t ( ) g e n . n e x t ( )
22. ݟํΛม͑Δͱ͍͔ʹ΋஗ԆϦετ d o n e : f a l s e v a l u e ( ) = > d o n e : f a l s e v a l u e ( ) = > d o n e : t r u e v a l u e
23. d o n e : f a l s e v a l u e x = > d o n e : f a l s e v a l u e y = > d o n e : t r u e v a l u e .next() ͸Ҿ਺ΛͱΕΔ
24. fetch().then(x => fetch().then(y => fetch().then(z => doSomething(x, y, z) ) ) ); PromiseΛ࢖ͬͨඇಉظॲཧ
26. d o n e : f a l s e v a l u e x = > d o n e : f a l s e v a l u e y = > d o n e : t r u e v a l u e
27. t h e n v a l u e x = > t h e n v a l u e y = > re s o l v e v a l u e .then() Ͱͭͳ͗߹ΘͤΔ
28. co(function* () { const x = yield fetch(); const y = yield fetch(); const z = yield fetch(); return doSomething(x, y, z); }); Promise + Generator + co
29. Q . ଞ ʹ ΋ δΣω Ϩ ʔ λ ͕ ࢖ ͑Δ ৔ ໘ ͸ ͋ Δʁ
30. A . ͋ Γ · ͢
31. 5 . ύ ʔ α ί ϯ Ϗω ʔ λ
32. symbol("(").bind(_ => expr.bind(x => symbol(")").bind(_ => pure(x) ) ) ); ׅހ (ʙ) ʹೖͬͨࣜͷύʔα
33. qo(function* () { yield symbol("("); const x = yield expr; yield symbol(")"); return x; }); ద౰ͳؔ਺Λ࢖͑͹……
34. 6 . * ద ౰ ͳ Ϟ φ υ ※ Ͳ ΕͰ ΋ ྑ ͍ ͱ ͍ ͏ Θ ͚ Ͱ ͸ ͳ ͍
35. δΣω Ϩ ʔ λ Λ ༗ ޮ ׆ ༻ ͠ ୂ ׆ ಈ ใ ࠂ
36. δΣω Ϩ ʔ λ ͸ ஗ Ԇ Ϧε τ Λ Ұ ൠ Խ ͠ ͨ Α ͏ ͳ ΋ ͷ
37. · ͩ · ͩ ࢖ ͑Δ ৔ ໘ ͕ ͋ Γ ͦ ͏ ྫ : ύ ʔ α ί ϯ Ϗω ʔ λ
38. ଞ ʹ ׆ ༻ ࣄ ྫ ͕ ͋ Ε ͹ ͓ ڭ ͑͘ ͩ ͞ ͍
39. { d o n e : t r u e , v a l u e : " T h a n k s " }