Destructuring

var [x,y] = [1,2];
// x=1, y=2
[x,y] = [y,x];
// x=2, y=1

const obj = { foo: "bar", bar: "foo" };
const {foo: f, bar} = obj;
// f = "bar", bar = "foo";

const twoRandos = () => [Math.random(), Math.random()];
const randos = twoRandos();
// [0.45235454, 0.6455656]
const [random1, random2] = twoRandos();
// random1 = 0.45235454, random2 = 0.6455656