在JavaScript中删除对象

本文翻译自：Deleting Objects in JavaScript

I'm a bit confused with JavaScript's delete operator. 我对JavaScript的delete操作符有点困惑。 Take the following piece of code: 采取以下代码：

var obj = {helloText: "Hello World!"
};var foo = obj;delete obj;

After this piece of code has been executed, obj is null , but foo still refers to an object exactly like obj . 在执行了这段代码之后， obj为null ，但是foo仍然引用与obj完全相同的obj 。 I'm guessing this object is the same object that foo pointed to. 我猜这个对象与foo指向的对象相同。

This confuses me, because I expected that writing delete obj deleted the object that obj was pointing to in memory—not just the variable obj . 这让我感到困惑，因为我期望写delete obj删除了obj指向内存的对象 - 而不仅仅是变量obj 。

Is this because JavaScript's Garbage Collector is working on a retain/release basis, so that if I didn't have any other variables pointing to the object, it would be removed from memory? 这是因为JavaScript的垃圾回收工作在保留/释放的基础，所以，如果我没有指向对象的任何其他变量，将它从内存中删除？

(By the way, my testing was done in Safari 4.) （顺便说一句，我的测试是在Safari 4中完成的。）

#1楼

参考：https://stackoom.com/question/37Bn/在JavaScript中删除对象

#2楼

based on @Guffa 's answer. 根据@Guffa的回答。 I found the following method works for me: 我发现以下方法适合我：

var obj = {helloText: "Hello World!"
};obj = null;delete obj;

By setting the obj to null first, you removed all the reference to it, then you can delete it completely. 通过首先将obj设置为null ，您删除了对它的所有引用，然后您可以完全删除它。

I didn't test it on other browser, but this works in phonegap 1.7.0 我没有在其他浏览器上测试它，但这适用于phonegap 1.7.0

#3楼

Aside from the GC questions, for performance one should consider the optimizations that the browser may be doing in the background -> 除了GC问题，对于性能，我们应该考虑浏览器可能在后台进行的优化 - >

http://coding.smashingmagazine.com/2012/11/05/writing-fast-memory-efficient-javascript/ http://coding.smashingmagazine.com/2012/11/05/writing-fast-memory-efficient-javascript/

It appears it may be better to null the reference than to delete it as that may change the behind-the-scenes 'class' Chrome uses. 看起来删除引用可能比删除它更好，因为这可能会改变Chrome使用的幕后“类”。

#4楼

I stumbled across this article in my search for this same answer. 我在寻找同样的答案时偶然发现了这篇文章。 What I ended up doing is just popping out obj.pop() all the stored values/objects in my object so I could reuse the object. 我最终做的只是弹出obj.pop()我对象中的所有存储值/对象，以便我可以重用该对象。 Not sure if this is bad practice or not. 不确定这是不好的做法。 This technique came in handy for me testing my code in Chrome Dev tools or FireFox Web Console. 这种技术对我在Chrome开发工具或FireFox Web控制台中测试代码非常方便。

#5楼

Setting a variable to null makes sure to break any references to objects in all browsers including circular references being made between the DOM elements and Javascript scopes. 将变量设置为null可确保在所有浏览器中中断对对象的任何引用，包括在DOM元素和Javascript范围之间进行循环引用。 By using delete command we are marking objects to be cleared on the next run of the Garbage collection, but if there are multiple variables referencing the same object, deleting a single variable WILL NOT free the object, it will just remove the linkage between that variable and the object. 通过使用delete命令，我们在下一次运行Garbage集合时标记要清除的对象，但是如果有多个变量引用同一个对象，则删除单个变量将不释放该对象，它将只删除该变量之间的链接和对象。 And on the next run of the Garbage collection, only the variable will be cleaned. 并且在下一次运行垃圾收集时，只会清除变量。

#6楼

Just found a jsperf you may consider interesting in light of this matter. 刚刚发现了一个jsperf你可能会认为这件事很有趣。 (it could be handy to keep it around to complete the picture) （保持它完成图片可能很方便）

It compares delete , setting null and setting undefined . 它比较delete ，设置null和设置undefined 。

But keep in mind that it tests the case when you delete/set property many times. 但请记住，当您多次删除/设置属性时，它会测试这种情况。

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在JavaScript中删除对象

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