JS 深拷貝的三種實(shí)現(xiàn)方式

1、將對(duì)象轉(zhuǎn)換為JSON字符串形式，再將其轉(zhuǎn)換為原生JS對(duì)象；

//_tmp和result是相互獨(dú)立的，沒(méi)有任何聯(lián)系，有各自的存儲(chǔ)空間。 let deepClone = function (obj) {     let _tmp = JSON.stringify(obj);//將對(duì)象轉(zhuǎn)換為json字符串形式     let result = JSON.parse(_tmp);//將轉(zhuǎn)換而來(lái)的字符串轉(zhuǎn)換為原生js對(duì)象     return result; };  let obj1 = {     weiqiujaun: {         age: 20,         class: 1502     },     liuxiaotian: {         age: 21,         class: 1501     } };  let test = deepClone(obj1); console.log(test);

2、使用JS中的for循環(huán)實(shí)現(xiàn)遍歷和復(fù)制；

function deepClone(obj) {     let result = typeof  obj.splice === "function" ? [] : {};     if (obj && typeof obj === 'object') {         for (let key in obj) {             if (obj[key] && typeof obj[key] === 'object') {                 result[key] = deepClone(obj[key]);//如果對(duì)象的屬性值為object的時(shí)候，遞歸調(diào)用deepClone,即在吧某個(gè)值對(duì)象復(fù)制一份到新的對(duì)象的對(duì)應(yīng)值中。             } else {                 result[key] = obj[key];//如果對(duì)象的屬性值不為object的時(shí)候，直接復(fù)制參數(shù)對(duì)象的每一個(gè)鍵值到新的對(duì)象對(duì)應(yīng)的鍵值對(duì)中。             }          }         return result;     }     return obj; }  let testArray = ["a", "b", "c", "d"]; let testRes = deepClone(testArray); console.log(testRes); console.log(typeof testRes[1]);  let testObj = {     name: "weiqiujuan",     sex: "girl",     age: 22,     favorite: "play",     family: {brother: "son", mother: "haha", father: "heihei"} }; let testRes2 = deepClone(testObj); testRes2.family.brother = "weibo"; console.log(testRes2);

3、利用數(shù)組的“Array.prototype.forEach”方法進(jìn)行復(fù)制即可實(shí)現(xiàn)深拷貝。

let deepClone = function (obj) {     let copy = Object.create(Object.getPrototypeOf(obj));     let propNames = Object.getOwnPropertyNames(obj);     propNames.forEach(function (items) {         let item = Object.getOwnPropertyDescriptor(obj, items);         Object.defineProperty(copy, items, item);      });     return copy; };  let testObj = {     name: "weiqiujuan",     sex: "girl",     age: 22,     favorite: "play",     family: {brother: "wei", mother: "haha", father: "heihei"} } let testRes2 = deepClone(testObj); console.log(testRes2);

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