Question

说我有代码：

function Obj(){
  var _x = 5;
  this.getX = function(){
    return _x;
  };
}

var obj = new Obj();

function God(){
  var x = obj.getX(); // i want 5 here
}

function Human(){
  var x = obj.getX(); // i want error/undefined here
}

var x = obj.getX(); // i want error/undefined here too

如何隐藏除{1}以外的所有对象的getX属性？

Answer 1

假设您通过God和Human使用new God和new Human作为对象，则可以使用锁和键来允许使用正确的类型：

function Obj(lock) {
    var _x = 5;
    this.getX = function (key) {
        if (key instanceof lock) {
            return _x;
        }
    };
}

function God() {
    var x = obj.getX(this);
    console.log(x);
}

function Human() {
    var x = obj.getX(this);
    console.log(x);
}

var obj = new Obj(God);
var g = new God();   // logs 5
var h = new Human(); // logs undefined

当然，人们总是可以选择锁定：

function Thief() {
    var g = new God();
    var x = obj.getX(g);
}

var t = new Thief(); // logs 5

此锁定的另一种方法＆amp;关键机制是通过共享秘密：

function Obj(lock) {
    var _x = 5;
    this.getX = function (key) {
        if (lock === key) {
            return _x;
        }
    };
}

(function (scope) {
    //When I wrote this, only God and I understood what I was doing
    //Now, God only knows
    var secret = {};
    scope.God = function () {
        var x = scope.obj.getX(secret);
        console.log(x);
    };
    scope.obj = new Obj(secret);
}(window));

function Human() {
    var x = obj.getX();
    console.log(x);
}

var g = new God();
var h = new Human();

Answer 2

然后将该方法仅添加到一个对象

见下面的例子。

＆＃13;

function  K(){ 
  this.name = 'Mr. K' 
}

var k1 = new K()

k1.getX = function() { 
  console.log(this.name) 
}
k1.getX(); // prints Mr.K

var k2 = new K()
k2.getX() // Error Uncaught TypeError: k2.getX is not a function

＆＃13;

Answer 3

单向：
参考：How do you find out the caller function in JavaScript?

检查Obj中的来电者功能名称，如上文所述，并采取相应的行动，但不能在严格模式下使用。

从javascript中除了一个对象之外的所有对象隐藏对象属性

3 个答案: