JavaScript:闭包中的自动获取器和设置器没有eval? [英] JavaScript: automatic getters and setters in closures without 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

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())

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