用私有变量创建单例的方法？ [英] Ways to create a singleton with private variables?

问题描述

我正在尝试创建一个单变量，其变量不能从外部直接更改。这是我当前的代码：

I'm trying to create a singleton that has variables not directly mutable from the outside. This is my current code:

var singleton = new (function () {
    var asd = 1;
    this.__defineGetter__("Asd", function() {
        return asd;
    });
})();

alert(singleton.Asd) // test

但是，似乎就像很多丑陋的代码，只是为了实现一个简单的事情。

However, it seems like alot of ugly code just to achieve a simple thing.

用这样的 private 变量创建单例的更干净的替代方法是什么？

What are some cleaner alternatives to create a singleton with such private variables?

推荐答案

我认为只有闭包才能在JavaScript中带来真正的私有变量。通常，我们使用某种命名约定来告诉变量是否为私有。

I think only closure can bring real private variable in JavaScript. Usually we use some kind of naming convention to tell if the variable is private.

var TheStaticClass;

(function () {
  var a=1;
  TheStaticClass.__defineGetter__("A", function() {
    return a;
  });
})();

alert(TheStaticClass.A) // test

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