function num(x, y, z) { return x + y + z; } const arr = [5, 6, 7]; num(...arr) // 18
function num(...args){ return args.filter(el => el % 2 === 0); } num(1,2,3,4,5,6); // [2,4,6]
합치기 (다음 요소에 펼쳐진다)
let arr1 = [1,2,3]; let arr2 = [4,5,6]; arr1 = [...arr1, ...arr2]; // [1, 2, 3, 4, 5, 6]
복사
let arr = [1,2,3]; let arr2 = [...arr]; arr2 // [1,2,3] arr2.push(4) arr2 // [1,2,3,4] arr // [1,2,3] --> 원본에 영향을 주지 않음
let obj1 = { name: "John", gender: "male" }; let obj2 = { name: "Harry", age: "26" } let clonedObj = {...obj1}; let mergedObj = {...obj1, ...obj2}; clonedObj // { name: "John", gender: "male" }; mergedObj // { name: "Harry", gender: "male", age: "26" }