[JS] 전개 구문

전개 구문

배열에서 사용

let arr1 = [1,2,3];
let arr1 = [1,2,3];

let result = [0, ...arr1, ...arr2, 7,8,9];
//[0, 1, 2, 3, 1, 2, 3, 7, 8, 9]

객체에서의 사용

let user = {name : 'mike'}
let mike = {...user, age:30}
console.log(mike);

//{name: 'mike', age: 30}

let arr = [1,2,3];
let arr2 = [...arr];

console.log(arr2);
//(3) [1, 2, 3]

let user = {name:'Mike', age:30};
let user2 = {...user};

user2.name = 'tom';

console.log(user);
console.log(user2);
//{name: "Mike", age: 30}
//{name: "tom", age: 30}

활용

let user = {name : 'mike'};
let info = {age : 30};
let fe = ["js", "react"];

user = {
  ...user,
  ...info,
  skills : [...fe]
};
console.log(user);

//{name: "mike", age: 30, skills: Array(2)}
//name: "mike"
//age: 30
//skills: Array(2)
//0: "js"
//1: "react"