javascript - 在javascript中修改对象值的问题

Question

我有以下代码。

var emp={"EmployeeLists":[{"ID":1,"NAME":"Anbu","Salary":80000},{"ID":2,"NAME":"Anand","Salary":90000}]};

// Inserting a new object into EmployeeLists
emp.EmployeeLists.splice(2,0,emp.EmployeeLists[1])
console.log(JSON.stringify(emp));

输出: {"EmployeeLists":[{"ID":1,"NAME":"暗部","Salary":80000},{"ID":2, "NAME":"Anand","Salary":90000},{"ID":2,"NAME":"Anand","Salary":90000}]}

// Modifying inserted object NAME Anand into MANI
emp.EmployeeLists[2].NAME="MANI";
console.log(JSON.stringify(emp));

输出: {"EmployeeLists":[{"ID":1,"NAME":"暗部","Salary":80000},{"ID":2, "NAME":"**MANI**","Salary":90000},{"ID":2,"NAME":"**MANI**","Salary":90000}]}

添加新对象后。我试图将该对象的名称 Anand 修改为 MANI 但它被修改为对象的名称 Two 和 Three .

Answer 1

好问题!您所看到的是对象的底层共享，因为如果您不小心，Javascript 会 secret 地将对象视为 C 中的指针。让我们重写它来制作对象的克隆。我们将使用 this previous Stackoverflow answer (在 Javascript 中克隆对象非常烦人)。

function clone(obj) {
    if (null == obj || "object" != typeof obj) return obj;
    var copy = obj.constructor();
    for (var attr in obj) {
        if (obj.hasOwnProperty(attr)) copy[attr] = obj[attr];
    }
    return copy;
}

emp.EmployeeLists.splice(2, 0, clone(emp.EmployeeLists[1]));
emp.EmployeeLists[2].NAME = "MANI";
// {"EmployeeLists":[{"ID":1,"NAME":"Anbu","Salary":80000},{"ID":2,"NAME":"Anand","Salary":90000},{"ID":2,"NAME":"MANI","Salary":90000}]}