JavaScript

2021年度リクルート エンジニアコース新人研修の講義資料です

Transcript

1. JavaScript Bootcamp 2021 2021, 26 April @ Recruit Kento TSUJI @maxmellon
2. ΍Δ͜ͱɺ΍Βͳ͍͜ͱ ΍Δ͜ͱ ΍Βͳ͍͜ͱ ɾ ϥΠϒϥϦͷ࢖͍ํ ɾ build΍preprocessपΓ ɾ ϨΨγʔͳه๏ͷৄࡉ (஌͓ͬͯ͘͜ͱ͸ॏཁ) ɾ جຊతͳه๏ ɾ ΫϥΠΞϯτ࣮૷ ɾ View ͱ ϩδοΫͷ ੾Γ෼͚ ޙͰݟ͓ͯ͘ͱྑͦ͞͏ͳ΋ͷ https://github.com/asciidwango/js-primer js-primer Ͱݕࡧ
3. ࠓ೔ͷྲྀΕ 1. JavaScript ͷجຊ 2. ԋश
4. ৮ͬͯΈΑ͏
5. ͱΓ͋͑ͣಈ͔ͯ͠ΈΔ PDF ͰΈ͍ͯΔํ΁ : gifΞχϝͳͷͰදࣔ͞Ε·ͤΜ
6. $ node -v v14.16.1 $ node > // ͜͜ͰJavaScriptΛ࣮ߦ͢Δ͜ͱ͕Ͱ͖·͢ undefined > 1 + 1; 2 > var test = "hoge"; undefined > test 'hoge' > function sample() { ... var num = 5; ... return num; ... } undefined > sample() 5
7. ϒϥ΢βͰ΋ಈ͔ͯ͠ΈΔ
8. Chrome Devtools ΞυϨεόʔ͔Β http://example.com ΁ΞΫηε ͜Ε
9. Node.js ͷ REPLͷΑ͏ʹ ࣮ߦͰ͖Δ ϩάग़ྗʹՃ͑ͯ࠷ޙͷࣜͷ݁Ռ͕දࣔ͞ΕΔ
10. ௨৴಺༰ΛΈͯΈΔ
11. Chrome Devtools ͜Ε
12. ͕͜͜੺͘ͳ͍ͬͯΔͷΛ֬ೝ͔ͯ͠ΒϦϩʔυ͢Δ C
13. JavaScript ͷ ϑΝΠϧΛ ࡞ͬͯಈ͔ͯ͠ΈΔ
14. Hello World PDF ͰΈ͍ͯΔํ΁ : gifΞχϝͳͷͰදࣔ͞Ε·ͤΜ
15. $ touch helloworld.js $ code helloworld.js $ node helloworld.js Hello World 01 02 console.log('Hello World');
16. αʔόʔαΠυͷ JavaScript ͱ ΫϥΠΞϯταΠυͷ JavaScript • Ұൠతʹ Node.js Ͱಈ͔͢ JavaScript Λ αʔόʔαΠυͷ JavaScript • ϒϥ΢βͰಈ͔͢ JavaScript Λ ΫϥΠΞϯταΠυͷ JavaScript
17. JavaScript ͷ Syntax
18. Variable declaration ม਺ ɾ એݴ
19. Variable declaration είʔϓ ࠶୅ೖ Մม
    
    ෆม DPOTU MFU WBS
20. Variable declaration είʔϓ ࠶୅ೖ Մม
    
    ෆม DPOTU ϒϩοΫ ෆՄ Մม MFU ϒϩοΫ Մೳ Մม WBS ؔ਺ Մೳ Մม
21. είʔϓ let a = 1; if (a === 1) { let a = 2; console.log(a); // 2 } console.log(a); // 1 ϒϩοΫ var a = 1; if (a === 1) { var a = 2; console.log(a); // 2 } console.log(a); // 2 ؔ਺ (άϩʔόϧ)
22. ࠶୅ೖ ͱ ՄมɺෆՄม ؔ਺ (άϩʔόϧ) const ͸ ࠶୅ೖෆՄೳ const a = 1 a = 2 Uncaught SyntaxError: Identifier 'a' has already been declared const ࠶୅ೖ͕Ͱ͖ͳ͍͚ͩͰॻ͖׵͑ΕΔ const a = [] a.push(1) console.log(a) // [1] a.pop() console.log(a) // []
23. ͲΕ͔ͭ͑͹͍͍ͷʁ • ࠶୅ೖ͸ϩδοΫΛෳࡶԽͤ͞Δ͜ͱ͕ଟ͍ → جຊతʹ const • Ͳ͏ͯ͠΋࠶୅ೖ͍ͨ͠ͱ͖ → let • var ͸ lint Ͱېࢭ͢Δ͜ͱ΋ଟ͍
24. ࣜͱจ
25. ࣜͱจ • JavaScript ͸ จ (Statement) ͱ ࣜ (Expression) ͔Βߏ੒͞Ε͍ͯΔ • ࣜ͸ධՁ͢Δͱ݁Ռͷ஋͕͋Δ • จ͸ॲཧͷ̍εςοϓ • ࣜ͸จʹͳΕΔ
26. ࣜ • ؆୯ʹݴ͏ͱม਺ʹ୅ೖͰ͖Δ΋ͷ • 13 ΍ ‘foo’ ͱ͍ͬͨϦςϥϧ • bar ͱ͍͏ ม਺ • ؔ਺ࣜ (ޙड़) ͳͲͳͲ
27. ࣜ // 1 ͸͔ࣜͩΒ୅ೖͰ͖Δ const a = 1 // JavaScript ͷੈքͰ͸ؔ਺΋ࣜ const doSomeThing = function() { console.log('doSomeThing') } // ؔ਺͕୅ೖ͞Ε͍ͯΔͷͰݺͼग़͢͜ͱ͕Ͱ͖Δ doSomeThing()
28. จ • จ͸ॲཧ͢Δ 1 εςοϓ • จ຤ʹ ; Λ͚ͭΔͱ จͷ۠੾ΓʹͳΔ • ; Λ͚ͭͳͯ͘΋ ASI ͕উखʹ ; Λ͍ΕΔ • if จ ΍ for จ ΋จ͔ͩΒ୅ೖͰ͖ͳ͍ ΦʔτηϛίϩϯΠϯαʔγϣϯ
29. ϒϩοΫจ • {, } Λ࢖ͬͯෳ਺ͷจΛؚΉจΛॻ͚Δ { console.log("hoge"); console.log("poge"); } if (true) { console.log("hoge"); console.log("poge"); } • ྫ : if จͱϒϩοΫจͷ૊Έ߹Θͤ
30. function
31. ؔ਺એݴͱؔ਺ࣜ function Greeting() { console.log('hello') } • จͱࣜͱ͍͏͜ͱ͕ҧ͏ • એݴ͸ר্͖͕͛ى͖Δ const Greeting = function() { console.log('hello') } ؔ਺એݴ ؔ਺ࣜ
32. ؔ਺ࣜͱΞϩʔϑΝϯΫγϣϯ • ୹͔͚͘Δ • ΞϩʔϑΝϯΫγϣϯ͸ this Λଋറ͠ͳ͍ ؔ਺ࣜͱΞϩʔϑΝϯΫγϣϯͷҧ͍ ୹͔͚͘ΔͷͰΞϩʔϑΝϯΫγϣϯΛ࢖͏৔໘͸ଟ͍ const Greeting = function() { console.log('hello') } const Greeting = () => { console.log(‘hello') }
33. ଋറͱ͸ 5IJT 8JOEPX %PDVNFOU *OTUBODF
    " • ϝϞϦ্ͷ object ͱࣝผࢠ Λඥ෇͚Δ͜ͱ • JavaScript ͷΞϩʔؔ਺Ͱͳ͍ؔ਺͸ this ͱ͍͏ࣝผࢠʹ ର࣮ͯ͠ߦ͢ΔίϯςΩετʹԠͯ͡ඥ෇͚Δ object ͕มΘΔ
34. JavaScript ʹ͓͚Δ this • Ξϩʔؔ਺Ҏ֎ͷؔ਺ • Ϋϥε • ΦϒδΣΫτ • bindؔ਺ this ͷ ίϯςΩετ ͕มΘΔ৔໘ Ұൠతͳݴޠͱ
    UIJT
    ͕ҧ͏ͱݴΘΕΔͷ͸
    UIJTͷίϯςΩετ͕มΘͬͯ͠·͏͔Β https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Operators/this ࠓ͸׬શͳཧղ͡Όͳͯ͘΋ྑ͍ Θ͔Βͳ͘ͳͬͨΒௐ΂Α͏
35. ΞϩʔϑΝϯΫγϣϯ const foo = (a, b) => { return a + b } ΞϩʔϑΝϯΫγϣϯͰ͸͕ࣜҰͭͷͱ͖ʹݶΓϒϩοΫΛলུ͔͚ͯ͠Δ const foo = (a, b) => a + b // ·ͨ͸ const foo = (a, b) => ( a + b
 ) ϒϩοΫΛলུͨ͠৔߹ɼͦͷࣜΛ࣮ߦͨ݁͠Ռ͕ return ͞ΕΔ
36. Ҿ਺ function doSomeThing(a, b, c = 0) {
 console.log('a %o', a) console.log('b %o', b) console.log('c %o', c) } doSomeThing(1, 2) // a 1 // b 2 // c 0 doSomeThing(...[1, 2, 3]) // a 1 // b 2 // c 3 function doSomeThing(...args) {
 console.log('args %o', args) } doSomeThing(1, 2, 3) // args [1, 2, 3] doSomeThing([1], 2, 3) // args [[1], 2, 3] doSomeThing(...[1, 2, 3]) // args [1, 2, 3] σϑΥϧτҾ਺ Մม௕
37. object
38. Objectͱ͸ • σʔλͱػೳͷू߹ • ϓϩύςΟͱϝιου͕ઃఆͰ͖Δ
39. ྫ const person = { name: ['Bob', 'Smith'], age: 32, gender: 'male', interests: ['music', 'skiing'], bio() { alert(`${this.name.join(' ')} is ${this.age} years old.`); }, greeting() { alert('Hi! I\'m ' + this.name[0] + '.'); } }
40. objectʹ͓͚Δmethod const person = { greeting() { alert('Hi!'); } }; const person = { greeting: function() { alert('Hi!'); } }; • ӈͷํ͕୹͔͚͘Δ • ҙຯ͸શ͘ಉ͡
41. const person = { _age: 25, _name: 'maxmellon', get age() { return this._age; }, get name() { return this._name; } }; ήολʔ΍ηολʔ͕࢖͑Δ
42. Object Λ࡞Δ const age = 26 const name = 'Kento TSUJI' const parson = { age: age, name: name, } ͜Ε͸ ͜͏͔͚Δ const age = 26 const name = 'Kento TSUJI' const parson = { age, name, }
43. Object ͔Β஋ΛऔΓग़͢ const age = parson.age const name = parson.name ͜Ε͸ ͜͏͔͚Δ const { age, name } = parson
44. Object Λίϐʔ͢Δ const copied = { ...parson } const copied = Object.assign({}, parson) Object.assign ʹΑΔ Shallow Copy εϓϨου ʹΑΔ Shallow Copy Object ͕ωετͨ͠ͱ͖ɼ ࢠͷObjectͷࢀর͸มԽ͠ͳ͍͜ͱʹ஫ҙ ԋࢉࢠ͡Όͳ͍͚ͲԿނ͔ εϓϨουԋࢉࢠͱΑ͘ݴΘΕ͕ͪ (MDN্΋Ұ࣌ظ͸ԋࢉࢠදهͩͬͨ) Object.assign ͱ εϓϨουߏจ ͸Ұݟྨࣅ͍ͯ͠Δ͕ҧ͍͕͋ΔͷͰ஫ҙ ಛʹ Object.prototype ͕ॻ͖׵͑ΒΕ͍ͯΔ৔߹ ಘΒΕΔ΋ͷ͕มΘ͖ͬͯ·͢ JavaScript ͷ࢓༷ ϨϕϧͰ શ͘ผͷૢ࡞Λߦ͍ͬͯ·͢ (assign ͸ Set, spread ͸ CreateDataPropertyOrThrow
45. Object ΛϚʔδ͢Δ const a = { foo: 1, hoge: 'a', } const b = { hoge: 'b', poge: 2, } const merged = { ...a, ...b } { foo: 1, hoge: 'b', poge: 2, } ϚʔδͰ΋ `spread` ͕࢖͑Δ
46. class
47. ΫϥεએݴͱΫϥεࣜ class Hoge { method() { 
 } } const Hoge = class { method() { } } • Ϋϥεએݴ͸ ר্͖͕͛ى͖ͳ͍ const Hoge = class Hoge { method() { } } Ϋϥεએݴ Ϋϥεࣜ ໊લ෇͖Ϋϥεࣜ
48. class Rectangle { constructor(height, width) { this.height = height; this.width = width; } // ήολʔ get area() { return this.calcArea(); } // ϝιου calcArea() { return this.height * this.width; } } const square = new Rectangle(10, 10); console.log(square.area); // 100 square.height = 20; // 'aaaa' https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Classes ϝιουఆٛ
49. Tips • JavaScript͸prototypeϕʔεͷݴޠ • class ͸ prorotypeͱObjectΛ࢖ͬͨ දݱΛ؆ܿʹΘ͔Γ΍͘͢ॻͨ͘Ίͷ΋ͷ • ͳͷͰ͍ΘΏΔΠϯελϯεϝιου͸ AnyClass.prototype.method ͷΑ͏ʹදݱ͢Δ ↑ ͜Ε͸ new AnyClass().method() • ελςΟοΫؔ਺͸AnyClass.staticMethod ࣮࣭తʹ͸౶ҥߏจ͚ͩͲɼclassߏจͰॻ͔Εͨ΋ͷΛ prototype Ͱਖ਼֬ʹ࠶ݱ͢Δͷ͸ͪΐͬͱେม
50. ༨ஊ private class field
51. Ϟμϯͳϒϥ΢βͰ͸private field ͕࢖͑Δ • ϨΨγʔϒϥ΢βͰ࢖͏ʹ͸ transpile ͳͲͷϓϦϓϩηε͕ඞཁ https://github.com/tc39/proposal-private-fields/blob/master/OLD_README.md class Point { #x = 0; #y = 0; constructor(x = 0, y = 0) { this.#x = +x; this.#y = +y; } get x() { return this.#x } set x(value) { this.#x = +value } get y() { return this.#y } set y(value) { this.#y = +value } }
52. Ϟμϯͳϒϥ΢βͰ͸private field ͕࢖͑Δ • ϨΨγʔϒϥ΢βͰ࢖͏ʹ͸ transpile ͳͲͷϓϦϓϩηε͕ඞཁ https://github.com/tc39/proposal-private-fields/blob/master/OLD_README.md class Point { #x = 0; #y = 0; constructor(x = 0, y = 0) { this.#x = +x; this.#y = +y; } get x() { return this.#x } set x(value) { this.#x = +value } get y() { return this.#y } set y(value) { this.#y = +value } }
53. ಉظ / ඇಉظ
54. ΋͠ඇಉظ͕ͳ͔ͬͨΒͲ͏ͳΔ͔ • αʔόʔ͔ΒσʔλΛड͚औΔ·Ͱ ଞͷૢ࡞͕Ͱ͖ͳ͍ • ΫϦοΫ͢Δͱϒϥ΢β͕ݻ·Δ • ॲཧ͕Ұ͔ͭͣͭ͠Ͱ͖ͳ͍ • ϒϥ΢βͷ JavaScript ͸ ݪଇγϯάϧεϨου (main thread) Ͱ࣮ߦ͞ΕΔ (worker ͳͲ΋͋Δ) Α͋͘Δצҧ͍ : γϯάϧεϨου === ಉظॲཧ͔͠ͳ͍ ࣮ࡍʹ͸Πϕϯτϧʔϓͱ͍͏΋ͷͰλεΫΛΩϡʔͰ؅ཧͯ͠ ͦͷ࣌఺࣌఺Ͱಈ͔͢΂͖ॲཧΛΩϡʔ͔ΒऔΓग़ͯ͠ॲཧ͍ͯ͠Δ
55. Πϕϯτϧʔϓ ֓ཁ
    
    
    
    4DSJQU
    
    
    
    5JNFS
    
    
    
    &WFOU
    DMJDL
    NPVTFNPWF
    
    .JDSPUBTL
    
    3FOEFS
    
    .JDSPUBTL
    
    3FOEFS <script src=”…”> ϒϥ΢βͷ rendering ͳʹ͔͠ΖͷλεΫ࣮ߦத͸ rendering ͞Εͳ͍ .addEventListener(…) ͷ callback setTimeout(() => {}) ͷ callback Promise ɾɾɾ
56. callback ʹΑΔඇಉظ taskA(() => { taskB(() => { taskC(() => { }) }) }) • ͍ͭऴΘΔ͔Θ͔Βͳ͍ taskA ʹ callback ؔ਺Λ ౉ͯ͠ऴΘ͔ͬͯΒ࣮ߦ͢ΔॲཧΛҠৡ͢Δ ωετ͕ͲΜͲΜਂ͘ͳͬͯ͠·͏
57. promise
58. promise new Promise((resolve, reject) => { asynchronizedTask((err, result) => { if (err) reject(err) resolve(result) }) }).then(res => console.log(res)) .catch(err => console.error(err)) • ඇಉظॲཧͷந৅Խ • then Ͱ ੒ޭͨ͠ͱ͖ͷϋϯυϥΛ ෇༩͢Δ ৽͍͠PromiseΛฦ͢ (ݫີʹ͸ࣦഊϋϯυϥ΋௥ՃͰ͖Δʣ • catch Ͱ ࣦഊϋϯυϥͷίʔϧόοΫΛ෇༩͢Δ
59. promise QSPNJTF UIFO IBOEMFS
    UIFO 
    IBOEMFS
    
    DBUDI PO3FKFDUJPO FSSPS
    IBOEMJOH QSPNJTF UIFO IBOE
    UIFO 
    IBOE
    DBUDI PO3FKF ଴ػঢ়ଶ ੒ޭ ࣦഊ promise͕ࣦഊͨ͠ͱ͖ thenͷୈೋҾ਺ͷhandlerͰྫ֎͕ग़ͨͱ͖ return return ੒ޭ ࣦഊ thenͷϋϯυϥ͸ඞͣPromiseΛฦ͢ͷͰ chainͰ͖Δ chainͰ͖Δ
60. example new Promise(resolve => { // 1ඵޙʹ ୈ1Ҿ਺ͷؔ਺Λ࣮ߦ͢Δ setTimeout(() => resolve(1), 1000) }) .then(res => { console.log(res) return res + 1 }) .then(res => { console.log(res) return res + 1 }) .then(res => { console.log(res) }) ࣮ߦ͢ΔͱͲΜͳϩάग़ྗ͞ΕΔʁ
61. fetch API const url = 'https://hacker-news.firebaseio.com/v0/item/ 2921983.json?print=pretty' fetch(url) .then(resp => resp.json()) .then(resp => console.log(resp)) • ྫ͑͹ɼhacker news ͷ API Λୟ͘ͱ͢Δ { "by" : "norvig", "id" : 2921983, "kids" : [ 2922097, 2922429, 2924562, 2922709, 2922573, 2922140, 2922141 ], "parent" : 2921506, "text" : "Aw shucks, guys ... you make me blush with your compliments.<p>Tell you what, Ill make a deal: I'll keep writing if you keep reading. K?", "time" : 1314211127, "type" : "comment" }
62. async / await
63. async function const url = 'https://hacker-news.firebaseio.com/v0/item/ 2921983.json?print=pretty' const fetchAsync = async () => { try { const resp = await fetch(url) return resp.json() } catch (err) { console.error(err) } } await fetchAsync() ಉظؔ਺ͷΑ͏ʹPromiseΛѻ͏ Promise Λ async / await Ͱॻ͚Δ
64. Module
65. Ϟδϡʔϧͷྺ࢙ • <script> λά ΍ prototype.js ͳͲ…. • AMD (RequireJS) • Browserify • UMD • ESModules ࠓ͸׬શͳཧղ͡Όͳͯ͘΋ྑ͍ ࿩͢ͱΩϦ͕ແ͘ͳΔ ͍Ζ͍Ζ ͋ͬͨ
66. ࠓ೔ͷԋशͰ࢖͏΋ͷ Webଆ : ESModules APIଆ : CommonJS import doSomeThing from './doSomeThing.js' const a = 1 export default a const doSomeThing = require('./doSomeThing') const a = 1 module.exports = a Import / export ͸ಛʹෳࡶɼ໊લ෇͖ ΍ default, as ͳͲ৭ʑͰ͖Δ෼ෳࡶ ࡉ͔͘͸ԋशͰ࢖͍ͳ͕Βղઆ
67. DOM
68. DOM ͷ ૠೖ const parent = document.createElement("div"); const child = document.createElement("span"); parent.appendChild(child); console.log(parent); // <div><span></span></div> ଞʹ΋ insertBefore, replaceChild ౳͕͋Δ
69. DOM ͷ࡟আ // ਌ཁૉ͕ෆ໌ɺෆఆͷ৔߹ͷํ๏ const node = document.getElementById("nested"); if (node.parentNode) { node.parentNode.removeChild(node); } DOM ʹؔ͢Δ API ͸ https://qiita.com/uhyo/items/1c565b61d934cbb88c2e ͳͲ͕Θ͔Γ΍͍͢
70. SPA Λ࡞Δ্Ͱ େ੾ͳ͜ͱ
71. SPAΛ࡞Δ্Ͱॏཁͳ͜ͱ • View ͱ ϩδοΫΛ੾Γ཭͢ 7JFX ϩδοΫ มߋස౓ : ߴ มߋස౓ : ௿ ςετ೉౓ : ߴ ςετ೉౓ : ௿ ViewͱϩδοΫ͕ີ݁߹ʹͳΔͱ ςετ͕ॻ͖ʹ͔ͬͨ͘Γ มߋʹऑ͘ͳͬͨΓ͢Δ
72. View ͱ ϩδοΫΛ੾Γ཭͢ • MVC (Model-View-Controller) • MVVM (Model-View-ViewModel) • Flux • ͳͲͳͲ… ViewͱϩδοΫΛ੾Γ཭ͨ͢Ίʹ༷ʑͳΞʔΩςΫνϟύλʔϯ͕༗Δ
73. ࠔͬͨͱ͖Ͳ͏͢Δ͔
74. ࠔͬͨͱ͖ • ׂ͍͔ͭ͘Ѫͨ͠΋ͷ͕͋Γ·͢ ԋࢉࢠ : https://jsprimer.net/basic/operator/ σʔλܕ : https://jsprimer.net/basic/data-type/ ৚݅෼ذ : https://jsprimer.net/basic/condition/ ϧʔϓ : https://jsprimer.net/basic/loop/ ޙͰݟ͓ͯ͘ͱྑͦ͞͏ͳ΋ͷ https://github.com/asciidwango/js-primer js-primer Ͱݕࡧ
75. ex. JavaScript ͔Β DOMΛ࡞Γ͍ͨ • ҰൠͷهࣄΑΓ΋ ͳΔ΂͘ MDN ΛಡΉบΛ ʢݚमͱ͍͏ҙຯ΋ࠐΊͯʣ • ௐ΂ͯΘ͔Βͳ͔ͬͨͱ͖͸ ԿΛͨͯ͘͠ɼͲ͏ௐ΂͔ͨ ڞ༗ͯ͘͠ΕΔͱخ͍͔͠΋
76. ԋश 1. JavaScript ͷجຊ 2. ԋश
77. ԋशͷ৺ߏ͑ • ՝୊ΛऴΘΒͤΔ͜ͱΛ໨తͱ͠ͳ͍Ͱ͍ͩ͘͞ • पΓͷਓͷਐḿΛؾʹ͢Δඞཁ͸͋Γ·ͤΜ • ࣭໰͢Δલʹࣗ෼ͳΓʹෆ໌఺Λਪଌͯ͠ΈΑ͏ • JavaScript ݚमલΑΓগ͠Ͱ΋ JavaScript Λ ॻ͚ΔΑ͏ʹͳ͍ͬͯͩ͘͞
78. ίʔεબ୒ ϏΪφʔίʔε Ξυόϯευίʔε JavaScript ॻ͍ͨ͜ͱແ͍ਓ޲͖ `javascripting` ͱ͍͏υϦϧ ΛਐΊΔɺ͕࣌ؒ༨Ε͹ TODO ؅ཧΞϓϦ։ൃ React.js / Vue.js ౳ Λ׆༻ͯ͠ΞϓϦέʔγϣϯΛ։ൃͨ͜͠ͱ͋Δਓ޲͖ ༩͑ΒΕͨ HTML, CSS, API αʔό ͔Β ϑϧεΫϥονͰ TODO ؅ཧΞϓϦΛ׬੒ͤ͞Δ ϕʔγοΫίʔε JavaScript Λ গ͠ॻ͍ͨ͜ͱ͋Δਓ޲͖ લ೚ऀͷυΩϡϝϯτΛ ݩʹ ్த·Ͱ։ൃ͞Εͨ TODO ؅ཧΞϓϦΛ׬੒ͤ͞Δ
79. ͦΕͧΕͷ໨ඪઃఆ ϏΪφʔίʔε Ξυόϯευίʔε ϕʔγοΫίʔε JavaScript Λ ಡΈ / ॻ͖ Ͱ͖ΔΑ͏ʹͳΔ ਓͷॻ͍ͨ JavaScript ΛಡΊΔΑ͏ʹͳΓ JavaScript ͔Β DOMΛ׆༻Ͱ͖ΔΑ͏ʹͳΔ ػೳΛ࣮૷͢ΔͷʹՃ͑ͯ ந৅Խ΍ΞʔΩςΫνϟύλʔϯΛ ࣗ෼Ͱ࣮૷͢Δͷʹ௅ઓ
80. ϏΪφʔίʔε
81. ४උ $ npm install @recruit-tech/javascripting -g $ javascripting ↑ ͜ΕΛ࣮ߦ ↓ Έ͍ͨͳը໘͕ͰΕ͹ OK
82. ೔ຊޠ΁ͷม͑ํ
83. ϕʔγοΫίʔε ϕʔγοΫίʔε Ξυόϯευίʔε
84. ४උ • https://github.com/recruit-tech/ bootcamp-2021-js Λfork • README ʹैͬͯ ணख
85. ͦΕͰ͸ԋशʹ औΓ૊Έ·͠ΐ͏ʂ