Numbers in javascript

JSのNumberについて

Transcript

1. Numbers in javascript
   

   View Slide

2. Name
   @brn (ꫬꅿ⨳ⵃ)
   Occupation
   ؿٗٝزؒٝسؒٝآص،٥ط؎ذ؍ـؒٝآص،
   Company
   Cyberagent ،سذؙأةآؔ AI Messenger
   OSS
   Contributor of V8
   About
   http://info.b6n.ch
   

   View Slide

3. Number
   ES2016~2018׾穗גjavascriptך侧⦼㘗ח׮
   ְֻאַ㢌⻉ָ֮׏׋ךד׉ך鑧
   

   View Slide

4. Variations
   -  侭侧
   -  㼭侧
   -  16鹌侧
   -  8鹌侧
   -  2鹌侧
   -  Bigint
   -  Separator
   

   View Slide

5. 侭侧
   64bitתדך侭侧׾䪔ִ׷
   ⰻ鿇涸חכ㹋鄲⣛㶷׌ָ31bit侭侧ה64bit Doubleדⴽ׸גְ׋׶ծ
   64bit Doubleך׫׌׏׋׶
   

   View Slide

6. 㼭侧
   㼭侧挿
   הֻח鎉ֲֿה׮זְָծⰻ鿇涸חכ64bit DoubleדⳢ椚ׁ׸׷
   זךד鎘皾穠卓כ鵚⡂⦼חז׷
   

   View Slide

7. 16鹌侧
   0xדכׄת׷侧⦼
   CSSהַדֶזׄ׫
   

   View Slide

8. 8鹌侧
   0oדכׄת׷ַ
   0~ד7⟃♳ך侧⦼ָזְ㜥さח8鹌侧חז׷
   ؿ؋؎ٕػ٦ىحءّٝהַדֶזׄ׫
   

   View Slide

9. // 8進数!
   0o777!
   !
   // 暗黙の8進数
   0777!
   !
   // 0から始まる10進数
   0778!
   !
   "use strict";!
   0777 // Error!!
   

   View Slide

10. 2鹌侧
    0bַ׵㨣ת׷0ה1ך׫⢪欽〳腉זٔذٕٓ
    

    View Slide

11. // 2進数!
    0b11101101 // 237!
    

    View Slide

12. BigInt
    64bit⟃♳ך侧⦼׾䪔ֲ㜥さח⢪ֲ
    植㖈Stage3
    侧⦼ٔذٕٓך䖓׹ח n ׾אֽ׷ֿהדBigIntٔذٕٓ׾邌植ׅ׷կ
    HexװOctalٔذٕٓ׮؟ه٦زկ侧⦼ٔذٕٓהずֻׄn׾劣㽵ח
    אֽ׷ֿהדBigIntחז׷կ(׋׌׃ծOctalכ0oXXX䕎䒭ך׫)
    ת׋ծtypeof כ 'bigint'ָ䨱׷կ
    

    View Slide

13. // Bigint!
    10n + 10n // 20n!
    10n + 10 // Error!
    typeof 10n // 'bigint'!
    BigInt('100') // 100n!
    

    View Slide

14. BigInt
    鑫׃ֻכ
    https://speakerdeck.com/brn/ecmascript-bigint
    ח剅ְ׋
    

    View Slide

15. Separator
    植㖈Stage3
    ת׌mergeׁ׸גְזְָV8ח㹋鄲׃ג׫׋
    ׉ךֲ׍⢪ִ׷״ֲחז׷ծ✮㹀
    

    View Slide

16. // Numeric Separators!
    1_0_0_0_0!
    0xFF_FF_FF!
    0b1000_1111_0000!
    0o7_7_7!
    !
    1__0 // Error!
    1000_ // Error!
    

    View Slide

17. ׀幠耮֮׶ָהֲ׀ְׂת׃׋
    

    View Slide