tc39 proposals

Transcript

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

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

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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11. function save(filename = do { throw new TypeError("Argument required”) })

    { } // σϑΥϧτύϥϝʔλͰͷdoࣜ͸·ͩະఆ

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

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

    class.f(); } }

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