问题描述
如何在Javascript中创建静态变量?
How can I create static variables in Javascript?
推荐答案
如果您来自基于类的静态类型对象 - 面向语言(如Java,C ++或C#)我假设您正在尝试创建与类型相关但不与实例相关联的变量或方法。
If you come from a class-based, statically typed object-oriented language (like Java, C++ or C#) I assume that you are trying to create a variable or method associated to a "type" but not to an instance.
使用经典方法的示例,使用构造函数可以帮助您捕获基本OO JavaScript的概念:
An example using a "classical" approach, with constructor functions maybe could help you to catch the concepts of basic OO JavaScript:
function MyClass () { // constructor function
var privateVariable = "foo"; // Private variable
this.publicVariable = "bar"; // Public variable
this.privilegedMethod = function () { // Public Method
alert(privateVariable);
};
}
// Instance method will be available to all instances but only load once in memory
MyClass.prototype.publicMethod = function () {
alert(this.publicVariable);
};
// Static variable shared by all instances
MyClass.staticProperty = "baz";
var myInstance = new MyClass();
staticProperty
在MyClass对象中定义(这是一个函数)并且与其创建的实例无关,JavaScript将函数视为,因此作为对象,您可以为函数指定属性。
staticProperty
is defined in the MyClass object (which is a function) and has nothing to do with its created instances, JavaScript treats functions as first-class objects, so being an object, you can assign properties to a function.
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