数组对象的深拷贝

let arr = [1, {a: 2}];
 
function deepCopy(arr) {
    let copyArr = (arr.constructor === Array) ? [] : {}; // 判断是数组还是对象
    for(let i in arr) {
        if(typeof arr[i] === 'object') {   // 判断是值类型还是引用类型
            copyArr[i] = deepCopy(arr[i]);  // 引用类型的话进行递归操作
        } else {
            copyArr[i] = arr[i];  // 值类型直接赋值
        }
    }
    return copyArr;
}
 
let copyArr = deepCopy(arr);
console.log(copyArr )  // [1, {a: 2}]
arr[1].a = 3;
console.log(copyArr )  // [1, {a: 2}]
copyArr[1].a = 5;
console.log(arr)       // [1, {a: 2}

对象深拷贝

var obj = { a: 1, b: { c: 2 }};

// 深拷贝

var newObj = JSON.parse(JSON.stringify(obj));

function copyArr(arr) {
 const newArr = []  
arr.forEach(item => {
   const {...obj} = item
   newArr.push(obj)
 })
   return newArr
}

  function DeepCopy(object) {
            let resultObject = {};
            for (let obj in object) {
                if (typeof (object[obj]) == "object" && !Array.isArray(object[obj])) {
                    let x = {}
                    x[obj] = DeepCopy(object[obj])
                    Object.assign(resultObject, x);
                } else {
                    let x = {};
                    x[obj] = object[obj];
                    Object.assign(resultObject, x);
                }
            }
            return resultObject;
        }