在JavaScript对象中更改密钥名称

问题描述

我正在检查JavaScript对象中的属性，通过删除前缀element替换某些键并将新值保存在另一个对象中。

I am checking the attributes in a JavaScript object, replacing some of the keys by deleting the prefix "element" and saving the new values in another object.

var keys = Object.keys(json);
for (var j=0; j < keys.length; j++) {
   key = keys[j].replace("element_", "");
   switch(key) {
   default :
      tmp[key] = json[key];
      break;
   }
}

问题在于，当我这样做时，我可以记录所有键，它们具有正确的名称，但是当我尝试设置与这些键关联的值时，它们是未定义的（json [key]）。

The matter is that when I do that, I can log all the keys, they have the correct names, but when I try to set the values associated to these keys, they are undefined (json[key]).

是由于我将密钥（ Objects ）转换为字符串（使用）替换方法）？

Is that due to the fact that I converted the keys (Objects) to Strings (with the replace method)?

推荐答案

问题是你在原始对象中寻找属性使用新密钥。使用键[j] 而不是键：

The problem is that you are looking for the property in the original object using the new key. Use keys[j] instead of key:

var keys = Object.keys(json);
for (var j=0; j < keys.length; j++) {
   var key = keys[j].replace(/^element_/, "");
   tmp[key] = json[keys[j]];
}

我在替换中使用正则表达式，以便 ^ 可以匹配字符串的开头。这样它只会在它是前缀时替换字符串，并且不会将 noexample_data 转换为 no_data 。

I uses a regular expression in the replace so that ^ can match the beginning of the string. That way it only replaces the string when it is a prefix, and doesn't turn for example noexample_data into no_data.

注意：你所拥有的不是一个json，它是一个JavaScript对象。 JSON是一种表示数据的文本格式。

Note: What you have is not "a json", it's a JavaScript object. JSON is a text format for representing data.

否。键是字符串，而不是对象。

No. The keys are strings, not objects.

您还可以通过删除旧对象来更改原始对象中的属性。添加新：

You could also change the properties in the original object by deleting the old ones and adding new:

var keys = Object.keys(json);
for (var j=0; j < keys.length; j++) {
   if (keys[j].indexOf("element_") == 0) {
     json[keys[j].substr(8)] = json[keys[j]];
     delete json[keys[j]];
   }
}

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