Javascript 按名称获取对象作为字符串而不使用eval

Get object by name as string without eval

提问by Jeroen

The code below does what I want, but I would like to avoid eval. Is there a function in Javascript that looks up an object by its name as defined by in a string?

下面的代码做了我想要的，但我想避免eval. Javascript 中是否有一个函数可以通过字符串中定义的名称查找对象？

myobject = {"foo" : "bar"}
myname = "myobject";
eval(myname);

Some context: I am using this for an application in which a large number of nodes in the dom has a html5 data-objectattribute, which is used in the handler function to connect back to the model.

一些上下文：我将它用于一个应用程序，其中 dom 中的大量节点具有 html5data-object属性，该属性在处理程序函数中用于连接回模型。

Edit: myobject is neither global nor local, it is defined in one of the parent frames of the handler.

编辑：myobject 既不是全局的也不是局部的，它是在处理程序的父框架之一中定义的。

回答by thecodeparadox

If variables are global then:

如果变量是全局的，则：

myobject = {"foo" : "bar"};
myname = "myobject";
window[myname].foo

DEMO

演示

For local:

对于本地：

(function(){
    myobject = {"foo" : "bar"};
    myname = "myobject";
    alert( this[myname].foo );
})();

DEMO

演示

回答by jeff

Local Variable Solution:

局部变量解决方案：

You could make all objects that you want to access with a string properties of another object. For example:

您可以使用另一个对象的字符串属性创建要访问的所有对象。例如：

var objectHolder = {
    myobject: {"foo" : "bar"},
    myobject2: {"foo" : "bar"},
    myobject3: {"foo" : "bar"}
};

And then access your desired object like this:

然后像这样访问你想要的对象：

var desiredObject = objectHolder["myobject"];

---

---

Global Variable Solution:

全局变量解决方案：

You can access global variables using a string like this:

您可以使用这样的字符串访问全局变量：

window["myobject"];

回答by SurlyP

This question is pretty old, but since it's the top result on Google for the query "javascript get object from string", I thought I'd share a technique for longer object paths using dot notation.

这个问题已经很老了，但由于它是 Google 上查询“javascript get object from string”的最高结果，我想我会分享一种使用点表示法获得更长对象路径的技术。

Given the following:

鉴于以下情况：

var foo = { 'bar': { 'alpha': 'beta' } };

We can get the value of 'alpha' from a string like this:

我们可以从这样的字符串中获取 'alpha' 的值：

var objPath = "bar.alpha";

var alphaVal = objPath.split('.')
  .reduce(function (object, property) {

    return object[property];
  }, foo);

// alphaVal === "beta"

If it's global:

如果是全局的：

window.foo = { 'bar': { 'alpha': 'beta' } };

Just pass windowas the initialValuefor reduce:

只需window作为initialValuefor传递reduce：

var objPath = "foo.bar.alpha";

var alphaVal = objPath.split('.')
  .reduce(function (object, property) {

    return object[property];
  }, window);

// alphaVal === "beta"

Basically we can use reduceto traverse object members by passing in the initial object as the initialValue.

基本上我们可以reduce通过将初始对象作为initialValue.

MDN article for Array.prototype.reduce

Array.prototype.reduce 的 MDN 文章

回答by i--

since window is a global namespace, you could simply use

因为 window 是一个全局命名空间，你可以简单地使用

window[myname]