JavaScript库模式

我试图找出创建JavaScript库（类）的基本模式。我希望这样做，它不会用一堆垃圾来污染全局名称空间，而是允许类具有修改这些实例变量的实例变量和公共方法

考虑下面的玩具示例。我想制作一个类

Foo

。它应该包含一个实例成员，

bar

，它是一个数字。应该有一个

Foo

的构造函数，它接受一个数字并用该数字初始化其实例

bar

。应该有一个实例方法，我可以调用

Foo

对象来修改

bar

。可能使用库的代码如下所示：

var foo1 = new Foo(1);
var foo2 = new Foo(2);
console.log(foo1.bar); // should print "1"
console.log(foo2.bar); // should print "2"
foo2.changeBar(42);
console.log(foo1.bar); // should print "1"
console.log(foo2.bar); // should print "42"

生成的

foo.js

将由Web应用程序使用，因此通过HTML中的脚本标记包含

我已经用Google做了一些搜索，但是我还没有找到一个关于如何设计JavaScript类（用作库）的简洁、通用的大纲

这是最简单的方法。您不需要在闭包中包含定义，更像是一种样式。

可能是当今最流行的模式

var Foo = (function() {
    var _thisIsAPrivateVar;

    function thisIsAPrivateMethod() {
    }

    return {
        thisIsAPublicMethod : function() {
            // can still access the "private" variable and method
        }
    };

})();

---

以埃文的回答为基础，展示更多的可能性。不过，大多数正常情况下只使用其中的一部分

(function() {
    //When we create variables inside a function they can only be seen by other
    // inner functions. Wraping all our code here makes sure noone gets to see
    // the private stuff.

    //The first opening parenthesis is required for Javascript to parse it
    //correctly though


    //this is the constructor function
    //Note how we set a global variable (Foo) to make it available outside.
    Foo = function(num, another_num) {

        this.changeBar(num);

        //sometimes you will want to make a method that modifies a variable
        //that can't be acessed via this.xxx. You can use a closure here for that
        //(there are some performance considerations though)

        this.baz = function(){
            console.log(another_num);
        }

        //Setting methods "by hand" like this is also useful if you want to
        //do multiple inheritance, since you can just set all methods of the
        //second class by hand here if you want.
    }

    //Things on Foo.prototype will be available for all Foo objects,
    // via prototypal inheritance magic.
    Foo.prototype.changeBar = function(num) {
        this.bar = num;
    }

    var a_secret_variable = 42;

    function my_private_function(){
        console.log(a_secret_variable);
    }

    //All private variables can be normaly used (by functions that can see them).
    Foo.prototype.use_magic = function(){
        my_private_function();
    }

}());
 //The "fake" function is imediatelly called,
 //so in the end all it does is create a inner scope.

---

+1也是。关闭有一些微妙的优势。您可以在闭包内定义“private”函数，原型函数和成员函数可以调用该闭包。@selbie如何定义这样的私有函数，以及如何调用它？我已经编辑了Evan上面的答案，以包含私有方法。“privateMethod”函数只能由闭包中的其他函数调用。@selbie和Evan，事实上，现在我已经尝试过了，privateMethod不起作用。“this”被绑定到DOMWindow（我相信是因为它正在形成一个闭包？）可能是因为您的DOM事件没有绑定到正确的功能。执行某些操作单击“e.onclick=function（）{foo.changeBar（）；}；}”或使用“bind”关键字在回调之前显式设置this point apriorit。

(function() {
    //When we create variables inside a function they can only be seen by other
    // inner functions. Wraping all our code here makes sure noone gets to see
    // the private stuff.

    //The first opening parenthesis is required for Javascript to parse it
    //correctly though


    //this is the constructor function
    //Note how we set a global variable (Foo) to make it available outside.
    Foo = function(num, another_num) {

        this.changeBar(num);

        //sometimes you will want to make a method that modifies a variable
        //that can't be acessed via this.xxx. You can use a closure here for that
        //(there are some performance considerations though)

        this.baz = function(){
            console.log(another_num);
        }

        //Setting methods "by hand" like this is also useful if you want to
        //do multiple inheritance, since you can just set all methods of the
        //second class by hand here if you want.
    }

    //Things on Foo.prototype will be available for all Foo objects,
    // via prototypal inheritance magic.
    Foo.prototype.changeBar = function(num) {
        this.bar = num;
    }

    var a_secret_variable = 42;

    function my_private_function(){
        console.log(a_secret_variable);
    }

    //All private variables can be normaly used (by functions that can see them).
    Foo.prototype.use_magic = function(){
        my_private_function();
    }

}());
 //The "fake" function is imediatelly called,
 //so in the end all it does is create a inner scope.