JavaScript:闭包中的自动获取器和设置器没有eval?

问题描述

注意:关于JavaScript中的getter和setter的问题很多(请参见，javascript)， JavaScript中的字母和字母(正确的语法?)， javascript中的自动getter和setter(带有验证)， 等等).这些问题大多数涉及对象 Objects ，一些涉及 Closures ，很少涉及自动生成getter和set的问题.这个问题将在后面讨论.

Note: there are a lot of questions regarding getters and setters in JavaScript (see Javascript Getters And Setters, Getters and Setters in a function (javascript), Getters and Setters in JavaScript (Correct syntax ?), automatic getter and setter(with validation) in javascript, etc). Most of these questions deal with Objects, a few with Closures and rather few of them with automatically producing getters and sets. This question deals with the later.

answer 到也许是我想要的最接近的，但对于我的用例而言却不理想.

The answer to automatic getter and setter(with validation) in javascript is perhaps the closest for what I am looking for, but not-ideal for my use case.

当前，在我关闭时，我有以下内容:

Currently, in my closure I have the following:

function myClosure() {
  var closureVar1, closureVar2

  function do () { ... }

  function setupSettersAndGetters() {

    var closureVariables = ['closureVar1', 'closureVar2']

    for (var i = 0; i < closuredVariables.length; i++) {

      var currentClosureVariable = closureVariable[i]
      var toEvaluateString = "                                                 \
      do." + currentClosureVariable + " = function(value){                     \
        if(!arguments.length) return " + currentClosureVariable + ";           \
        " + currentClosureVariable + " = value;                                \
        return setup;                                                          \
      };                                                                       \
      "
      eval(toEvaluateString)
    }
  }
  setupSettersAndGetters()
  return do;
}

这完全符合我的意愿，例如

This works exactly as I like, e.g.

var test = myClosure()
test.closureVar1(10).closureVar2(2)
test.closureVar1() + test.closureVar2() // return 12

使用 eval 只是一个微小的"问题，有些人测试.

There is just the one "tiny" problem of using eval which some people detest.

所以我的问题是，有没有更好的方法来处理此问题，并允许我按名称而不是使用字符串来调用setter/getter?

So my question is, is there a better way to handle this and allow for me to call the setter / getter by name, rather than using a string?

例如我可以使用一个中间函数，例如:

e.g. I could use an intermediate function such as:

test.sget('closureVar1', 10) // set closureVar1 to 10
test.sget('closureVar2') // get closureVar2

但是即使这样做，我仍然需要使用 eval ?而且我更喜欢调用变量的名称...

but even doing that I think I still need to use eval? and I would prefer calling the name of the variable...

有想法吗?

推荐答案

您可以采用传递给 myClosure 函数的参数...

You can take the arguments passed to your myClosure function...

var args = Array.prototype.slice.call(arguments);

...并使用它们来设置您的setter和getter:

... and use them to set up your setters and getters:

args.forEach(function(arg) {
    instance[arg] = function(d) {
        if (!arguments.length) return arg;
        arg = d;
        return instance;
    };
});

这样，您可以传递所需的变量数量，并避免使用 eval .

That way, you can pass how many variables you want and also avoiding eval.

这是一个演示:

function myClosure() {
  var instance = {};
  var args = Array.prototype.slice.call(arguments);
  args.forEach(function(arg) {
    instance[arg] = function(d) {
      if (!arguments.length) return arg;
      arg = d;
      return instance;
    };
  })
  return instance;
};

var test = myClosure("v1", "v2", "v3")
test.v1(16).v2(2).v3(8)
console.log(test.v1() + test.v2() + test.v3())

这篇关于JavaScript:闭包中的自动获取器和设置器没有eval?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！