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js对象深拷贝

由于引用类型(数组、对象)是按地址传递,直接拷贝是浅拷贝,即修改拷贝后的变量,原变量也会改变。有时需要深拷贝一个对象,这时就需要遍历彻底复制,使原对象和拷贝对象完全脱离关系。

代码:

    function deepCloneObj(obj){        var i;        var o = Array.isArray(obj) ? [] : {};        for(i in obj){            if(obj.hasOwnProperty(i)){                o[i] = typeof obj[i] === "Object"? deepCloneObj(obj[i]) : obj[i];            }        }        return o;    }

实现细节:假定传入的是一个引用类型,首先判定传入的是数组还是对象,根据判定结果,确定o是初始化为空数组还是空对象。之后遍历传入引用类型的自有属性,并判定属性是否为对象,如果是的话做递归,否则直接复制给o。

数组实例:

    var arr1 = ["sfsag","akghak","[‘fafa‘,‘gaag‘,‘rwet‘]",125];    console.log(arr1);//["sfsag", "akghak", "[‘fafa‘,‘gaag‘,‘rwet‘]", 125]    var arr2 = deepCloneObj(arr1);    arr1.push("newstr");    console.log(arr1);//["sfsag", "akghak", "[‘fafa‘,‘gaag‘,‘rwet‘]", 125, "newstr"]    console.log(arr2);//["sfsag", "akghak", "[‘fafa‘,‘gaag‘,‘rwet‘]", 125]

对象实例:

    var obj1 = {sgsh:{sfwg:‘ssgsg‘},asga:[‘aff‘,‘ghh‘,‘wegwer‘,12],segg:1};    console.log(obj1);//Object {sgsh: Object, asga: Array[4], segg: 1}    var obj2 = deepCloneObj(obj1);    obj1[‘newstr‘] = [‘fsg‘,‘gsr‘];    console.log(obj1);//Object {sgsh: Object, asga: Array[4], segg: 1, newstr: Array[2]}    console.log(obj2);//Object {sgsh: Object, asga: Array[4], segg: 1}

 

js对象深拷贝