复制带有吸气剂结果的对象

问题描述

我有一个包含吸气剂的对象.

myObject {
    id: "MyId",
    get title () { return myRepository.title; }
}

myRepository.title = "MyTitle";

我想获得一个像这样的对象

myResult = {
    id: "MyId",
    title: "MyTitle"
}

我不想复制吸气剂，所以:

myResult.title;                       // Returns "MyTitle"
myRepository.title = "Another title";
myResult.title;                       // Should still return "MyTitle"

我已经尝试:

• $.extend():但是它不会遍历getter. http://bugs.jquery.com/ticket/6145
• 根据建议的此处进行迭代的属性，但是不会迭代获取方法.
li>
• 当我使用angular时，按照建议此处.但是我只会得到属性，而不会得到吸气剂.

有什么主意吗?谢谢！

( (Update: You've since said you want non-enumerable properties as well, so it doesn't do what you want; see the second part of this answer below, but I'll leave the first bit for others.) The bug isn't saying that the resulting object won't have a title property, it's saying that the resulting object's title property won't be a getter, which is perfect for what you said you wanted.

Example with correct getter syntax:

// The myRepository object
var myRepository = { title: "MyTitle" };

// The object with a getter
var myObject = {
    id: "MyId",
    get title() { return myRepository.title; }
};

// The copy with a plain property
var copy = $.extend({}, myObject);

// View the copy (although actually, the result would look
// the same either way)
snippet.log(JSON.stringify(copy));

// Prove that the copy's `title` really is just a plain property:
snippet.log("Before: copy.title = " + copy.title);
copy.title = "foo";
snippet.log("After:  copy.title = " + copy.title);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<!-- Script provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 -->
<script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script>

Syntax fixes:

• Added missing var, =, and ;

• Removed duplicate property title

• Corrected the getter declaration syntax

---

If you want to include non-enumerable properties, you'll need to use Object.getOwnPropertyNames because they won't show up in a for-in loop, Object.keys, or $.extend (whether or not they're "getter" or normal properties):

// The myRepository object
var myRepository = { title: "MyTitle" };

// The object with a getter
var myObject = {
    id: "MyId"
};
Object.defineProperty(myObject, "title", {
  enumerable: false, // it's the default, this is just for emphasis,
  get: function() {
    return myRepository.title;
  }
});

snippet.log("$.extend won't visit non-enumerable properties, so we only get id here:");
snippet.log(JSON.stringify($.extend({}, myObject)));

// Copy it
var copy = Object.getOwnPropertyNames(myObject).reduce(function(result, name) {
  result[name] = myObject[name];
  return result;
}, {});

// View the copy (although actually, the result would look
// the same either way)
snippet.log("Our copy operation with Object.getOwnPropertyNames does, though:");
snippet.log(JSON.stringify(copy));

// Prove that the copy's `title` really is just a plain property:
snippet.log("Before: copy.title = " + copy.title);
copy.title = "foo";
snippet.log("After:  copy.title = " + copy.title);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<!-- Script provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 -->
<script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script>

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