Question

用于调试内存泄漏问题，我想知道函数闭包是否会像任何全局变量一样保存在内存中？

function() {
    var  blah;
    return function() {
    }
}

Answer 1

如果你的意思是内在功能，那就不会。当没有对函数对象的引用时，它将被丢弃。

function() A {
    var  blah = //someobject;
    return function() {
    }
}

var x = A();
//inner function and blah created
x = null;
//inner function (and the variable blah) can now be garbage collected

Answer 2

闭包就像垃圾收集类一样 - 也就是说，为每个创建的闭包分配了封闭变量：

function foo () {
    var x = 0;
    return function(){return x}
}

var a = foo(); // memory allocated for x
var b = foo(); // memory allocated for second instance of x

/* This is what I mean by it behaves like a class: returning the
 * inner function creates a new closure much like calling a class
 * with `new` creates a new object
 */

a = null; // memory for x will be de-allocated in the next round
          // of garbage collection

b = null; // memory for second x will be de-allocated eventually

function bar () {
    y = foo()
}

bar(); // memory for third instance of x is allocated when foo()
       // is called inside bar().

// memory for third instance of x will be de-allocated eventually
// after bar() returns because y has already been de-allocated

将关闭以保持整个生命的js代码？

2 个答案: