分割代入

値の交換

let x = 70;

let y = 30;

[x, y] = [y, x]

console.log(x);     //30

console.log(y);    //70

const foo = ['one', 'two', 'three'];

const [red, yellow, green] = foo;

console.log(red);　// "one"

console.log(yellow);　// "two"

console.log(green);　// "three"