js對象深拷貝

由於引用類型（數組、對象）是按地址傳遞，直接拷貝是淺拷貝，即修改拷貝後的變數，原變數也會改變。有時需要深拷貝一個對象，這時就需要遍歷徹底複製，使原對象和拷貝對象完全脫離關係。

代碼：

    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;
    }

實現細節：假定傳入的是一個引用類型，首先判定傳入的是數組還是對象，根據判定結果，確定o是初始化為空數組還是空對象。之後遍歷傳入引用類型的自有屬性，並判定屬性是否為對象，如果是的話做遞歸，否則直接複製給o。

數組實例：

    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]

對象實例：

    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}