js的数据类型分为基本数据类型和引用数据类型。基本数据类型是直接赋值，引用数据类型分为浅拷贝和深拷贝。浅拷贝是复制对象的指针，深拷贝是复制对象所有属性再内存中独立存在。
浅拷贝如下：
var obj = {a: ‘test‘, b: {c: 0}}var obj1 = objvar obj2 = shallowCopy(obj);function shallowCopy(src) { ???var dst = {}; ????for (var prop in src) { ????????if (src.hasOwnProperty(prop)) { ????????????dst[prop] = src[prop]; ?????????} ?????} ????return dst;}var obj3 = Object.assign({}, obj)obj.a = ‘arr‘obj.b.c = 1console.log(obj) // {a: ‘arr‘, b: {c: 1}}console.log(obj1) // {a: ‘arr‘, b: {c: 1}}console.log(obj2) // {a: ‘test‘, b: {c: 1}}console.log(obj3) // {a: ‘test‘, b: {c: 1}}深拷贝实现如下：
function extend (source) { ?var target ?if (typeof source === ‘object‘) { ???target = Array.isArray(source) ? [] : {} ???for (var key in source) { ?????if (source.hasOwnProperty(key)) { ???????if (typeof source[key] !== ‘object‘) { ?????????target[key] = source[key] ???????} else { ?????????target[key] = extend(source[key]) ???????} ?????} ???} ?} else { ???target = source ?} ?return target}var obj1 = {a: {b: 0}}var cpObj1 = extend(obj1)obj1.a.b = 1console.log(cpObj1) // {a: {b: 0}}var obj2 = [[0]]var cpObj2 = extend(obj2) obj2[0][0] = 1console.log(cpObj2) // [[0]]
js实现深拷贝
原文地址：https://www.cnblogs.com/zjp-zxy/p/9870658.html