Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
tc39 proposals
Search
Taketoshi Aono(青野健利 a.k.a brn)
October 09, 2019
Programming
0
720
tc39 proposals
tc39のproposals
throw expression
richer-keys
class-access-expression
Taketoshi Aono(青野健利 a.k.a brn)
October 09, 2019
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)
document.write再考
brn
6
2.7k
Parsing Javascript
brn
12
8k
JSON & Object Tips
brn
1
330
CA 1Day Youth Bootcamp for Frontend LT
brn
0
720
Modern TypeScript
brn
2
700
javascript - behind the scene
brn
3
640
プロダクト開発とTypeScript
brn
8
2.7k
React-Springでリッチなアニメーション
brn
1
540
javascript internationalization API
brn
0
730
Other Decks in Programming
See All in Programming
継続的な活動で築く地方エンジニアの道
myamashii
2
350
君たちはどうコードをレビューする (される) か / 大吉祥寺.pm
utgwkk
15
8.5k
【Go言語】golangci-lintの使い方
tomo1227
0
270
12年前の『型システム入門』翻訳の思い出話
mame
11
1.2k
【Go言語】ジェネリクス
tomo1227
0
170
リハビリmruby
kishima
1
160
20240706_CDKConf
takuyay0ne
0
1.2k
最古の関数型言語「Lisp」ことはじめ / lisp_in_kamiyama
uhooi
1
190
SRE チーム立ち上げ前に考えたこと・取り組んだこと / Considerations and Preparations Before Establishing an SRE Team
mackey0225
3
320
CSC307 Lecture 07
javiergs
PRO
0
220
Android開発者のための Kotlin Multiplatform入門
ntaro
0
190
[After Kotlin Fest 2024 LT Night @ Sansan] もっともっとKotlinを好きになる!K2 Compiler Pluginで遊んでみよう!
kitakkun
2
260
Featured
See All Featured
Exploring the Power of Turbo Streams & Action Cable | RailsConf2023
kevinliebholz
12
3.8k
Building Better People: How to give real-time feedback that sticks.
wjessup
357
18k
Navigating Team Friction
lara
181
13k
Sharpening the Axe: The Primacy of Toolmaking
bcantrill
26
1.6k
Learning to Love Humans: Emotional Interface Design
aarron
269
39k
Side Projects
sachag
451
42k
Product Roadmaps are Hard
iamctodd
PRO
48
10k
jQuery: Nuts, Bolts and Bling
dougneiner
61
7.4k
The Illustrated Children's Guide to Kubernetes
chrisshort
39
47k
ReactJS: Keep Simple. Everything can be a component!
pedronauck
662
120k
The Mythical Team-Month
searls
217
43k
Optimizing for Happiness
mojombo
373
69k
Transcript
tc39_study (throw_expressions) (Richer_Keys) (Class_Access_Expressions)
Name !CSO 5BLFUPTIJ"POP੨݈ར Occupation 'SPOUFOE%FWFMPQFS1SPEVDU0XOFS Company $ZCFSBHFOU"EUFDI4UVEJP"*.FTTFOHFS OSS $POUSJCVUPSPG7
About IUUQJOGPCODI
5ISPXFYQSFTTJPO
8IBUJTUISPXFYQSFTTJPO 5ISPXΛFYQSFTTJPO͔͠ॻ͚ͳ͍ॴͰॻ͚ΔΑ͏ʹͨ͠
function save(filename = throw new TypeError("Argument required")) { }
function getEncoder(encoding) { const encoder = encoding === "utf8" ?
new UTF8Encoder() : encoding === "utf16le" ? new UTF16Encoder(f alse) : encoding === "utf16be" ? new UTF16Encoder(t rue) : throw new Error("Unsupported encoding"); }
*NQMFNFOUBUJPO ࣮ੲ7ʹ࣮͠·ͨ͠ɻ݁ہ$-"CBOEPO͠·͕ͨ͠ɻ
1SPCMFN ࣮લఏͱͯ͠ 1SPQPTBMUP&YQMPSF&$."4DSJQU4UBUFNFOUTBT&YQSFTTJPOT IUUQTHJUIVCDPNSCVDLUPOQSPQPTBMTUBUFNFOUTBT FYQSFTTJPOTSFBENF ͱ͍͏ఏҊ͕TUBHFʹ͋ͬͨɻ TUBUFNFOUΛFYQSFTTJPOͱͯ͠औѻ͏͜ͱ͕Ͱ͖ΔΑ͏ʹ͢Δͱ͍͏ఏҊ
1SPCMFN ͨͩ͠ɺ&DNBTDSJQUʹ͓͚ΔTUBUFNFOUͱFYQSFTTJPOͷࠞಉ͕ ݴޠΛΑΓෳࡶʹͯ͠͠·͏ͷͰਐలͳ͘ UISPXFYQSFTTJPOʹؔͯ͠จ๏ͷՃʹରͯ͠ωΨςΟϒͳ͕݁ग़ͯ ͍ͯTUBHFʹਐΉ͜ͱͳͦ͞͏
%PFYQSFTTJPO ͦͯ͠ߋʹEPFYQSFTTJPOͱ͍͏QSPQPTBM͕ࠓճఏҊ͞Ε͍ͯΔશͯͷ TUBUFNFOUͱFYQSFTTJPOΛղܾͯ͠͠·͏ͷͰ ଟTUBHF͕ਐΉ͜ͱͳ͍͔͠Εͳ͍ɻ
function save(filename = do { throw new TypeError("Argument required”) })
{ } // σϑΥϧτύϥϝʔλͰͷdoࣜ·ͩະఆ
function getEncoder(encoding) { const encoder = encoding === "utf8" ?
new UTF8Encoder() : encoding === "utf16le" ? new UTF16Encoder(f alse) : encoding === "utf16be" ? new UTF16Encoder(t rue) : do { throw new Error("Unsupported encoding”); } }
1SPQPTBMSJDIFSLFZT
$PNQPTFEQSPQPTBM $PMMFDUJPO\UP,FZ UP7BMVF^ͱDPNQPTJUF,FZ DPNQPTJUF4ZNCPM ͷ̎ͭͷQSPQPTBMͷΈ߹Θͤ ͲͪΒΦϒδΣΫτͷࣝผʹ͍ͭͯ
$PMMFDUJPO\UP,FZ UP7BMVF^ $PMMFDUJPOʹUP,FZͱUP7BMVFΛՃ͢Δ
new Map([], { toKey(key) {return normalizedKey;}, toValue(value) {return normalizedValue;}, });
new WeakMap([], { toKey(key) {return normalizedKey;}, toValue(value) {return normalizedValue;}, }); new Set([], { toValue(value) {return normalizedValue;}, }); new WeakSet([], { toValue(value) {return normalizedValue;}, });
DPNQPTJUF,FZ DPNQPTJUF4ZNCPM ෳͷΦϒδΣΫτ͔ΒΩʔΛੜ͢Δ DPNQPTJUF,FZͱDPNQPTJUF4ZNCPM"1*ΛՃ͢Δ Ҿͷॱং͕ҧ͚Εҧ͏ΩʔͱͳΔ Ωʔʹར༻͞ΕͨΦϒδΣΫτ8FBL.BQͰཧ͞ΕΔͷͰΦϒδΣΫτ ͕ফ͑ΕϝϞϦ͔Βফ͑Δ
compositeKey(...parts: [...any]) : Object.freeze({__proto__:null}) compositeSymbol(...parts: [...any]) : Symbol()
const myValues = new Map(); const components = [a, b];
const myKey = compositeKey(...components); myValues.set(myKey, components); // ... let [a, b] = myValues.get(myKey);
4UBUVT UP,FZ͚ͩTUBHFʹͳΓ·ͨ͠ɻ UP7BMVF͕ඞཁ͔Ͳ͏͔͕TUBHFͰͷٞʹͳΓͦ͏
$MBTTBDDFTTFYQSFTTJPO
8IBUJTUIJT ΫϥεΦϒδΣΫτΞΫηε͢ΔҰ؏ͨ͠ํ๏Λఆٛ͢Δ
class C { static f() { ... } g() {
class.f(); } }
1SPCMFNTTPGBS TUBUJDͳΫϥεؔͷதͰUIJTΛͬͨ߹ɺؔͷݺͼग़͞ΕํʹΑͬͯ UIJT͕มΘΔ Ϋϥε໊Λͬͯ'PPCBSͱͨ͠߹ɺ'PPΛԿॻ͘ͷ%3:ʹͯ͠ ͍Δ UIJTDPOTUSVDUPS͔ΒࢀরͰ͖Δ͕ɺಉ͘͡UIJT͕TBGFͰͳ͍
%JTDVTT ࢀরํ๏͕૿͑Δͷ·͘͠ͳ͍ 'PPCBSͷΑ͏ʹΫϥε໊ͰΞΫηε͢Δͷ͕γϯϓϧͰΑ͍ %3:Λߟ͑ΔͱUIJTDPOTUSVDUPS͕ͩɺ҆શͰͳ͍ DMBTTCBSͰ͍͍͔͠Εͳ͍
4UBUVT 4UBHFʹͳΓ·ͨ͠