在属性名称位于变量中的情况下访问对象属性

我正在尝试检查JS对象中是否存在某个项目.为此，我需要使用传递给我的方法的任何ID.目前，我正在努力使用变量的值.这是我在做什么:

I am trying to check if a certain item exists in a JS object. To do this, I need to use whatever ID is passed into my method. At the moment I'm struggling to actually use the variable's value. Here's what I'm doing:

data.entries.id

所以我将对象设置为:

var data = { 
  "entries" : { 
  }
};

因此，.id部分将检查是否存在某个ID.如果可以，我什么都不做，如果不可以，我想添加它.目前，通过使用data.entries.id，每次我只是简单地检查"entries"中是否存在"id"，而这并不是我想要的.假设我的变量值是'part1'，那么我希望它不是data.entries.id而是要寻找data.entries.part1.

Therefore, the .id part will check if a certain ID exists. If it does, I do nothing, if it doesn't, I want to add it. At the moment, by using data.entries.id, every time I simply check if 'id' exists in 'entries' which is not what I want. Let's say my variable value was 'part1' then instead of data.entries.id I want it to look for data.entries.part1.

因此，当我检查变量名时，如何传递变量的值，而不是变量名.

So, how do I pass in the variable's value when I check for this, as opposed to the variable name.

我希望这是有道理的，希望您能提供帮助！

I hope that makes sense, and I hope you can help!