javascriptの分割代入

//基本 配列っぽく一括で代入
const [a, b, c] = [1, 2, 3]; //a=1,b=2,c=3

// 配列を利用
const ary = [1, 2, 3];
const [a, b, c] = ary; //a=1,b=2,c=3

//値の入れ替え
let [a, b] = [1, 20];
[a, b] = [b, a]; //a=20,b=1

//複数の戻り値の受け取り
function threeNum() {
  return [1, 2, 3];
}
const [a, b, c] = threeNum(); //a=1,b=2,c=3

//スプレッド演算子
const [a, b, ...rest] = [1, 2, 3, 4, 5]; //a=1,b=2,rest=3,4,5

//デフォルト引数
const [a = 1, b = 2, c] = [, , 3]; //a=1,b=2,c=3


//オブジェクト
const tom = {
  name: 'Tom',
  age: 20,
  gender: 'male',
};
const { name, age } = tom; //name=Tom,age=20