如何在javascript中释放闭包的内存? [英] how to release closure's memory in javascript?

问题描述

闭包:

function test() {
  var count = 0;

  return function() {
    count++;
  };
}

众所周知， count 在调用 test()后不会释放，现在如果闭包对我没有用，我该如何释放内存呢?

As we all know, the count won't release after test() be called, and now if the closure is useless to me, how could I release memory of it?

推荐答案

javascript中的所有对象都是垃圾收集的，无论它们是否参与关闭都不受天气影响.在上面的代码中，如果您这样做:

All objects in javascript is garbage collected, regardless of weather they're involved in a closure or not. In your code above, if you do:

var x = test();

然后当然不能释放用于 count 的内存，因为以后可能会被 x 使用.但是，如果您这样做:

then of course the memory for count cannot be released because it may be used later by x. However if you do:

var x = test();
x = "";

count 的内存迟早会被垃圾回收.

the memory for count will be garbage collected sooner or later.

此外，如果您这样做:

function foo () {
    var x = test();
    x();
}

foo();

count 的内存也将被垃圾回收，因为当 foo()结束时， x 超出范围.

the memory for count would also be garbage collected because x goes out of scope when foo() ends.

确保您的JavaScript中没有内存泄漏的最佳方法是避免使用全局变量.

The best way to ensure you don't have memory leaks in javascript is to avoid global variables.

注意:IE的旧版本中的垃圾收集器使用简单的引用计数，这意味着不会对垃圾桶中的循环数据结构进行垃圾收集.这已在IE6或IE7中修复，在其他通常使用标记清除垃圾收集器的JavaScript引擎中从来没有问题

Note: The garbage collector in old versions of IE used a simple reference count which means that circular data structures are not garbage collected. This was fixed in either IE6 or IE7 and was never a problem in other javascript engines which normally use a mark-and-sweep garbage collector

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