解决js函数闭包内存泄露问题的办法

function Cars(){ this.name = "Benz"; this.color = ["white","black"]; } Cars.prototype.sayColor = function(){ var outer = this; return function(){ return outer.color }; }; var instance = new Cars(); console.log(instance.sayColor()())

优化后的代码：

function Cars(){ this.name = "Benz"; this.color = ["white","black"]; } Cars.prototype.sayColor = function(){ var outerColor = this.color; //保存一个副本到变量中 return function(){ return outerColor; //应用这个副本 }; outColor = null; //释放内存 }; var instance = new Cars(); console.log(instance.sayColor()())

稍微复杂一点的例子：

function inheritPrototype(subType,superType){ var prototype = Object(superType.prototype); prototype.constructor = subType; subType.prototype = prototype; } function Cars(){ this.name = "Benz"; this.color = ["white","black"]; } Cars.prototype.sayColor = function(){ var outer = this; return function(){ return outer.color; }; }; function Car(){ Cars.call(this); this.number = [321,32]; } inheritPrototype(Car,Cars); Car.prototype.sayNumber = function(){ var outer = this; return function(){ return function(){ return outer.number[outer.number.length - 1]; } }; }; var instance = new Car(); console.log(instance.sayNumber()()());

首先，该例子组合使用了构造函数模式和原型模式创建Cars 对象，并用了寄生组合式继承模式来创建Car 对象并从Cars 对象获得属性和方法的继承；

其次，建立一个名为instance 的Car 对象的实例；instance 实例包含了sayColor 和sayNumber 两种方法；

最后，两种方法中，前者使用了一个闭包，后者使用了两个闭包，并对其this 进行修改使其能够访问到this.color 和this.number。

这里存在内存泄露问题，优化后的代码如下：

function inheritPrototype(subType,superType){ var prototype = Object(superType.prototype); prototype.constructor = subType; subType.prototype = prototype; } function Cars(){ this.name = "Benz"; this.color = ["white","black"]; } Cars.prototype.sayColor = function(){ var outerColor = this.color; //这里 return function(){ return outerColor; //这里 }; this = null; //这里 }; function Car(){ Cars.call(this); this.number = [321,32]; } inheritPrototype(Car,Cars); Car.prototype.sayNumber = function(){ var outerNumber = this.number; //这里 return function(){ return function(){ return outerNumber[outerNumber.length - 1]; //这里 } }; this = null; //这里 }; var instance = new Car(); console.log(instance.sayNumber()()());

以上就是为大家分享的解决方法，希望对大家的学习有所帮助。

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