This is an ES6 feature that allows us to extract properties from an object using an object pattern.
const obj = { a: 1, b: 2 }
let { a, b } = obj;
console.log(a); // 1
console.log(b); // 2
const arr = [1, 2, 3]
[x, y, z] = arr;
console.log(x); // 1
console.log(y); // 2
console.log(z); // 3