Ecmascript proposal-realms

現在提案中のtc39/proposal-realmsについて
ToKyoto.js#1

Transcript

1. Ecmascript Proposal-Realms
   

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2. せ⵸: @brn (ꫬꅿ⨳ⵃa.k.a ـٕ٦ظ)
   耵噟: ؿٗٝزؒٝسؒٝآص،٥iOSؒٝآص،
   ⠓爡: Cyberagent ،سذؙأةآؔRightSegment٥AI Messenger
   ـؚٗ: http://abcdef.gets.b6n.ch/
   Twitter: https://twitter.com/brn227
   GitHub: https://github.com/brn
   
   

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3. What is Relms?
   Realmsהכءٝفٕח鎉ֲהծ
   DOM搀׃Iframe٥Node.JSךVMٌآُ٦ٕ
   ׫׋ְז׮ך
   

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4. What can we do?
   Realms׾⢪ֲֿהדⴽךglobalؔـآؙؑز橆㞮ד
   ؝٦س晙׾evalׅ׷ֿהָדֹ׷կ
   

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5. let realm = new Realm();!
   !
   let outerGlobal = window;!
   let innerGlobal = realm.global;!
   !
   let f = realm.evalScript("(function() { return 17 })");!
   !
   f() === 17 // true!
   !
   Reflect.getPrototypeOf(f) ===
   outerGlobal.Function.prototype // false!
   !
   Reflect.getPrototypeOf(f) ===
   innerGlobal.Function.prototype // true!
   

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6. Hook some calls
   ת׋Realmsך؝ٝأزؙٓة٦חؔـآؙؑز׾床ֿׅהדぐ珏
   Hook׾㹋鄲ׅ׷ֿהָדֹ׷կ
   

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7. const r = new Realm({!
   evalHook(sourceText) {!
   return compile(sourceText);!
   },!
   importHook(referrerNamespace, specifier) {!
   ...!
   }!
   });!
   const result = r.eval('eval("1")');!
   // compile('1')を呼び出して、戻り値を評価する
   const ns = r.eval('import("foo")');!
   // referrerNamespaceがnullでspecifierが"foo"!
   

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8. Your own Realms
   Realmsכؙٓأזךד竰䪫׃ג荈ⴓ杝荈ך橆㞮׾欰䧭ׅ׷ֿהָד
   ֹ׷կ
   

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9. class FakeWindow extends Realm {!
   init() {!
   super.init();!
   // グローバルを初期化
   let global = this.global;!
   !
   // 各種グローバルオブジェクトを書き換え
   global.document = new FakeDocument(...);!
   global.alert = new Proxy(fakeAlert, { ... });!
   ...!
   }!
   }!
   

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10. Limitation
    植㖈ךהֿ׹evalScriptח湫䱸؝٦س׾床ׁזְה꼽湡կ
    㢩鿇أؙٔفز׾Realmsז橆㞮ד㹋遤׃׋ְկ
    
    https://github.com/tc39/proposal-realms/issues/71
    Realms.prototype.importScript
    ׾䲿周׃גֶֹת׃׋կ
    

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11. Status ת׌Stage-1זךד孡ꞿח䖉׍׋ְ
    

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12. Summary
    ➬✲ָ䎢デ噟歲זךד穠圓ⴖ㹋חק׃ְկ
    document.writeהַ׾剅ֹ䳔ִ׋ְ׿ׄׯ։
    

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