JavaScript中的隐私权 [英] Privacy in JavaScript

问题描述

函数作用域提供JavaScript中唯一的隐私。

Function scoping offers the only privacy in JavaScript.

所以规范：

function Ctor(dep1, dep2) {
  this._dep1 = dep1;
  this._dep2 = dep2;
}

Ctor.prototype.foo = function() {
  // use this._dep1/2...
}

...的问题在于它没有为注入的依赖项提供封装。

...is problematic in that it offers no encapsulation for the injected dependencies.

提供真正封装的替代方案（尽管在 foo 的位置方面略有不同）可能是：

An alternative (albeit slightly different in terms of location of foo) that offers real encapsulation might be:

function factory(dep1, dep2) {
  return {
    foo: partial(foo, dep1, dep2), // or use bind (partial could be a library fn for partial application)
  };
}

function foo(dep1, dep2) {
  // use dep1/2
}

但我很少看到这种模式。是否有充分的理由不使用后者？

But I rarely see this pattern. Is there a good reason to not use the latter?

推荐答案

您已经说明了第二种模式的优点。缺点是：

You already state the advantages of the second pattern. The disadvantages are:

• 您必须按可见性对方法进行分组（即使私有方法与公共方法密切相关，但几乎与其他私有方法无关），或重复对象文字中的所有公共方法（这对jsdoc不起作用）。

• you must either group methods by visibility (even if the private method is intimately related with a public one, but barely related to other private methods), or repeat all public methods in the object literal (which doesn't work well with jsdoc).

代码介绍一个单独的函数对象，用于你的类的每个实例，这会牺牲一些性能（这通常无关紧要，但有时可能会有所不同）

the code introduces a separate function object for every instance of your class, which sacrifices some performance (this usually doesn't matter, but sometimes might)

与许多私有修饰符不同编程语言，这种封装是无法规避的，即使误用，我真的知道自己在做什么（从历史上看，JavaScript一直是一个环境，任何事情都有，并且许多人将其成功归功于这种可扩展性）

unlike private modifiers in many programming languages, this encapsulation can not be circumvented, even if misapplied and I really know what I am doing (historically, JavaScript has been an environment where anything goes, and many attribute its success to this extensibility)

这篇关于JavaScript中的隐私权的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！