ES.next — 20年目のECMAScriptに向けて

社内勉強会で話した、ES.nextに関する話です

Transcript

1. ES.next 20೥໨ͷECMAScriptʹ޲͚ͯ גࣜձࣾSpeee ։ൃ෦ ೋࣾ୩ ߉༎ 1
2. ES = ECMAScriptͱ͸ • ECMA-262ͰఆΊΒΕͨεΫϦϓτݴޠͷ࢓༷ • JavaScript͸ECMAScriptͷ࣮૷ͳͷͰɺݫີʹ͸ΠίʔϧͰ ͸ͳ͍ • ECMAͷTC39ʹΑͬͯࡦఆ͞Ε͖ͯͨ • ES1͕1997ʹࡦఆ͞ΕͨͷͰɺདྷ೥Ͱ20೥Λܴ͑Δ 2
3. Contents • What's new in ES2015(ES6) • What's new in ES2016(ES7) • ECMAScriptͷࡦఆϓϩηε 3
4. What's new in ES2015(ES6) 4
5. ES2015Ͱ௥Ճ͞Εͨ΋ͷ • classߏจ • Ξϩʔؔ਺ • ObjectϦςϥϧͷ֦ு • ςϯϓϨʔτจ • ෼ׂ୅ೖ 5
6. ES2015Ͱ௥Ճ͞Εͨ΋ͷ • DefaultɺRest(࢒༨Ҿ਺)ɺSpread • let ͱ const • for .. of จ • δΣωϨʔλ yield, yield* • Unicodeαϙʔτͷ֦ு 6
7. ES2015Ͱ௥Ճ͞Εͨ΋ͷ • Ϟδϡʔϧ(import/export) • Map, Set, WeakMap, WeakSet • Proxy/Reflect • Symbol • ϏϧτΠϯΦϒδΣΫτͷαϒΫϥε 7
8. ES2015Ͱ௥Ճ͞Εͨ΋ͷ • Promise • Array, Math, Number, Object, Date, RegExp΁ͷػೳ௥Ճ • ܕ෇͖഑ྻ(Typed Arrays) • 2ਐ਺͓Αͼ8ਐ਺ͷ੔਺Ϧςϥϧ • ຤ඌݺग़͠࠷దԽ(tail call optimization) 8
9. What's new in ES2016(ES7) 9
10. ES2016Ͱ௥Ճ͞Εͨ΋ͷ(1) • Array.prototype.includes() [1, 2, 3].includes(2); // true [1, 2, 3].includes(4); // false [1, 2, 3].includes(1, 0); // true [1, 2, 3].includes(3, 3); // false 10
11. ES2016Ͱ௥Ճ͞Εͨ΋ͷ(2) • ΂͖৐ԋࢉࢠ 2 ** 2 // 4 2 ** -2 // 0.25 - 2 ** 2 // SyntaxError: Unexpected token ** -(2 ** 2) // -4 (-2) ** 2 // 4 11
12. Ҏ্ গͳ͍ͱࢥ͍·ͤΜ͔ʁ 12
13. ECMAScriptͷ࢓༷ࡦఆϓϩηε 13
14. ͍··ͰͷECMAScript • ES4͸ҙݟׂ͕Εͨ຤ʹഁغ͞Εͨ • ES2015ͷࡦఆʹ͕͔͔࣌ؒΓ͗ͨ͢ 14
15. ࣍ظECMAScriptͷ࢓༷ࡦఆϓϩηε • ϦϦʔε͕1೥ຖʹͳΔɻ໊લ΋೥߸ʹ(ES6 -> ES2015) • ௥Ճ࢓༷͸ਵ࣌ఏҊ͞ΕΔɻఏҊ͸Stage0(͖ͨͨ୆)ʙ Stage4(ࡦఆ׬ྃ)·Ͱͷ4ஈ֊ • ೥1ճͷTC39૯ձͷࡍʹStage4ʹͳ͍ͬͯΔ΋ͷ͕࢓༷ʹऔ Γࠐ·ΕΔ • ͦΕΒͷఏҊ·ͱΊͯES.nextͱݺͿ 15
16. ֤εςʔδ • Stage0 Strawman • Stage1 Proposal • Stage2 Draft • Stage3 Candidate • Stage4 Finished https://tc39.github.io/process-document/ 16
17. ͦͷ݁Ռ https://github.com/tc39/proposals/ 17
18. ͜Ε͔Β࠾༻͞Εͦ͏ͳ΋ͷ 18
19. ௥͍͔͚Δʹ͸ʁ ຖ೥ग़Δͱͨ͠ΒɺະରԠϒϥ΢βͷࠩҟຒΊΔͷେมͰ ͸…ʁ • BabelΛ࢖͏ • Polyfill࢖͏ 19
20. ES.next΁ͷContributeΛ͢Δʹ͸ʁ • όάใࠂ&मਖ਼ • ػೳͷϦΫΤετ • Proposal(ఏҊ)Λ্͛Δ https://github.com/tc39/proposals/blob/master/ CONTRIBUTING.md 20
21. ·ͱΊ • ES2015 ʹΑͬͯύϫϑϧʹͳͬͨECMAScript • ES2016 ͔Βࡦఆϓϩηε͕มߋ͞Εͨ • ES.next ΛܾΊΔͷ͸͋ͳͨ(͔΋͠Εͳ͍) 21