ES6 : Spread, Rest Operator

Spread Operator

...target 방식으로 사용

값을 복사하기 위해 사용

배열

let years = [2001,2010,2015,2018]; let yearsCp = [...years]; console.log(yearsCp);

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객체

let koreaHistory = { liberate : 1945, 625 : 1950 }; let history = { worldwar1 : 1914, worldwar2 : 1945, ...koreaHistory } console.log(history);

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defualt값을 설절해주고싶을때 사용

let address1 = { country : "South Korea", city : "Seoul" }; let address2 = { ...address1, country : "United State" } console.log(address2);

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Rest Operator

파라미터로 Spread Operator 를 받아서 사용

function printYears(...years){ console.log(years); } printYears(2000, 2001, 2010, 2015, 2018);

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// 결과 [ 2000, 2001, 2010, 2015, 2018 ]

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과거코드와 비교

// 과거 function printYears(years){ console.log(arguments); } printYears(2000, 2001, 2010, 2015, 2018);

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//결과 [Arguments] { '0': 2000, '1': 2001, '2': 2010, '3': 2015, '4': 2018 }

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