示例JS 数组和对象的深拷贝操作

let arr = [
 undefined,
 function(){
  console.log(123); 
 },
 true,
 null,
 {
  name:"123",
  age:23
 }
];
// arr作为拷贝对象

let arr1 = Array.from(arr);
arr[0] = 2;
console.log(arr1);
// [ undefined, [Function], true, null, { name: '123', age: 23 } ]

let arr1 = Object.assign([], arr)
arr[0] = 2;
console.log(arr1);
// [ undefined, [Function], true, null, { name: '123', age: 23 } ]

let arr1 = arr.slice(0);
arr[0] = 2;
console.log(arr1);
// [ undefined, [Function], true, null, { name: '123', age: 23 } ]

let arr1 = arr.concat();
arr[0] = 2;
console.log(arr1);
// [ undefined, [Function], true, null, { name: '123', age: 23 } ]

// let [...arr1] = arr; // 这两种都可以
let arr1 = [...arr];
arr[0] = 2;
console.log(arr1);
// [ undefined, [Function], true, null, { name: '123', age: 23 } ]

let obj = {
 name: "a",
 age: 20,
 sex: false,
 user: {
  a: 20,
  n: "b"
 },
 f: function(){
  return 1;
 },
 u: undefined,
 n: null
}

let obj1 = Object.assign({}, obj)
obj[age] = 2;
console.log(obj1);
// let obj = { name: "a", age: 20, sex: false,user: {a: 20,n: "b},f: function(){return 1;},u: undefined,n: null}