tc39 proposals

tc39のproposals
throw expression
richer-keys
class-access-expression

Transcript

1. tc39_study
   (throw_expressions)
   (Richer_Keys)
   (Class_Access_Expressions)
   

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2. Name
   !CSO 5BLFUPTIJ"POP੨໺݈ར
   
   Occupation
   'SPOUFOE%FWFMPQFS1SPEVDU0XOFS
   Company
   $ZCFSBHFOU"EUFDI4UVEJP"*.FTTFOHFS
   OSS
   $POUSJCVUPSPG7
   About
   IUUQJOGPCODI
   

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3. 5ISPXFYQSFTTJPO
   

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4. 8IBUJTUISPXFYQSFTTJPO
   5ISPXΛFYQSFTTJPO͔͠ॻ͚ͳ͍৔ॴͰ΋ॻ͚ΔΑ͏ʹͨ͠
   

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5. function save(filename = throw new TypeError("Argument required")) {
   }
   

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6. 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");
   }
   

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7. *NQMFNFOUBUJPO
   ࣮͸ੲ7ʹ࣮૷͠·ͨ͠ɻ݁ہ$-͸"CBOEPO͠·͕ͨ͠ɻ
   

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8. 1SPCMFN
   ࣮͸લఏͱͯ͠
   1SPQPTBMUP&YQMPSF&$."4DSJQU4UBUFNFOUTBT&YQSFTTJPOT
   IUUQTHJUIVCDPNSCVDLUPOQSPQPTBMTUBUFNFOUTBT
   FYQSFTTJPOTSFBENF
   ͱ͍͏ఏҊ͕TUBHFʹ͋ͬͨɻ
   TUBUFNFOUΛFYQSFTTJPOͱͯ͠औѻ͏͜ͱ͕Ͱ͖ΔΑ͏ʹ͢Δͱ͍͏ఏҊ
   

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9. 1SPCMFN
   ͨͩ͠ɺ&DNBTDSJQUʹ͓͚ΔTUBUFNFOUͱFYQSFTTJPOͷࠞಉ͕
   ݴޠΛΑΓෳࡶʹͯ͠͠·͏ͷͰਐల͸ͳ͘
   UISPXFYQSFTTJPOʹؔͯ͠΋จ๏ͷ௥Ճʹରͯ͠ωΨςΟϒͳ݁࿦͕ग़ͯ
   ͍ͯTUBHFʹਐΉ͜ͱ͸ͳͦ͞͏
   

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10. %PFYQSFTTJPO
    ͦͯ͠ߋʹEPFYQSFTTJPOͱ͍͏QSPQPTBM͕ࠓճఏҊ͞Ε͍ͯΔશͯͷ
    TUBUFNFOUͱFYQSFTTJPO໰୊Λղܾͯ͠͠·͏ͷͰ
    ଟ෼TUBHF͕ਐΉ͜ͱ͸ͳ͍͔΋͠Εͳ͍ɻ
    

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11. function save(filename = do { throw new TypeError("Argument required”) }) {
    }
    // σϑΥϧτύϥϝʔλͰͷdoࣜ͸·ͩະఆ
    

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12. 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”); }
    }
    

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13. 1SPQPTBMSJDIFSLFZT
    

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14. $PNQPTFEQSPQPTBM
    $PMMFDUJPO\UP,FZ UP7BMVF^ͱDPNQPTJUF,FZ DPNQPTJUF4ZNCPM
    ͷ̎ͭͷQSPQPTBMͷ૊Έ߹Θͤ
    ͲͪΒ΋ΦϒδΣΫτͷࣝผʹ͍ͭͯ
    

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15. $PMMFDUJPO\UP,FZ UP7BMVF^
    $PMMFDUJPOʹUP,FZͱUP7BMVFΛ௥Ճ͢Δ
    

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16. 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;},
    });
    

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17. DPNQPTJUF,FZ DPNQPTJUF4ZNCPM
    ෳ਺ͷΦϒδΣΫτ͔ΒΩʔΛੜ੒͢Δ
    DPNQPTJUF,FZͱDPNQPTJUF4ZNCPM"1*Λ௥Ճ͢Δ
    Ҿ਺ͷॱং͕ҧ͚Ε͹ҧ͏ΩʔͱͳΔ
    Ωʔʹར༻͞ΕͨΦϒδΣΫτ͸8FBL.BQͰ؅ཧ͞ΕΔͷͰΦϒδΣΫτ
    ͕ফ͑Ε͹ϝϞϦ͔Β΋ফ͑Δ
    

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18. compositeKey(...parts: [...any]) : Object.freeze({__proto__:null})
    compositeSymbol(...parts: [...any]) : Symbol()
    

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19. const myValues = new Map();
    const components = [a, b];
    const myKey = compositeKey(...components);
    myValues.set(myKey, components);
    // ...
    let [a, b] = myValues.get(myKey);
    

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20. 4UBUVT
    UP,FZ͚ͩTUBHFʹͳΓ·ͨ͠ɻ
    UP7BMVF͕ඞཁ͔Ͳ͏͔͕TUBHFͰͷٞ࿦ʹͳΓͦ͏
    

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21. $MBTTBDDFTTFYQSFTTJPO
    

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22. 8IBUJTUIJT
    ΫϥεΦϒδΣΫτ΁ΞΫηε͢ΔҰ؏ͨ͠ํ๏Λఆٛ͢Δ
    

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23. class C {
    static f() { ... }
    g() {
    class.f();
    }
    }
    

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24. 1SPCMFNTTPGBS
    TUBUJDͳΫϥεؔ਺ͷதͰUIJTΛ࢖ͬͨ৔߹ɺؔ਺ͷݺͼग़͞ΕํʹΑͬͯ
    UIJT͕มΘΔ
    Ϋϥε໊Λ࢖ͬͯ'PPCBSͱͨ͠৔߹ɺ'PPΛԿ౓΋ॻ͘ͷ͸%3:ʹ൓ͯ͠
    ͍Δ
    UIJTDPOTUSVDUPS͔ΒࢀরͰ͖Δ͕ɺಉ͘͡UIJT͕TBGFͰ͸ͳ͍
    

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25. %JTDVTT
    ࢀরํ๏͕૿͑Δͷ͸޷·͘͠ͳ͍
    'PPCBSͷΑ͏ʹΫϥε໊ͰΞΫηε͢Δͷ͕γϯϓϧͰΑ͍
    %3:Λߟ͑ΔͱUIJTDPOTUSVDUPS͕ͩɺ҆શͰ͸ͳ͍
    DMBTTCBSͰ΋͍͍͔΋͠Εͳ͍
    

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26. 4UBUVT
    4UBHFʹͳΓ·ͨ͠
    

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