let a = [1,2,3];

let b = [0, ...a, 4]; // [0,1,2,3,4]

let obj = { a: 1, b: 2 };

let obj2 = { ...obj, c: 3 }; // { a:1, b:2, c:3 }

let obj3 = { ...obj, a: 3 }; // { a:3, b:2 }

let a = [1,2,3];

let [b, ...c] = a;

b; // 1

c; // [2,3]

// 也可以

let a = [1,2,3];

let [b, ...[c,d,e]] = a;

b; // 1

c; // 2

d; // 3

e; // undefined

// 也可以

function test(a, ...rest){

  console.log(a); // 1

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

}

test(1,2,3)

let array = [1, 2, 3, 4, 5];

const [ x, y, ...z ] = array;

// 其中z=[3, 4, 5]，注意如果由于array的length不足以完成析构，则会导致z为[]

对象：

let obj = { name: 'zhangsan', age: 30, city: 'shenzhen' };

const {name, ...others} = obj;

console.log(name); // 'zhangsan'

console.log(others); // {age: 30, city: 'shenzhen'}