Question

如何使用IIFE模块模式在javascript中编写单例类？你能提供一个例子吗？

我尝试了类似的东西，但x2.getInstance失败了。根据我的理解，x2.getInstance（）应该获得与x1.getInstance（）相同的实例。如何使用IIFE模块模式实现这一点??

var x = (function(){

    var instance ;
    var vconstructor = function(){};
    //vconstructor.prototype.method1 = function(){}
    //vconstructor.prototype.method2 = function(){}
    vconstructor.prototype.getInstance = function(){
        if (!instance) {
          console.log('critical section');
          instance = somefunc();
          return instance;
    }
    };  

    function somefunc(){
        return { "key1": "value1"};
    }

    return vconstructor;
})();

var x1 = new x();
console.log('1.');
console.log(x1 instanceof x);
console.log(x1);
console.log('2.' + x1.getInstance());  
var x2 = new x();
console.log(x2);
console.log('x2: ' + x2.getInstance());

请告知。

Answer 1

你可以试试这个：

var Singleton = (function () {
    var instance;

    function createInstance() {
        var object = new Object("I am the instance");
        return object;
    }

    return {
        getInstance: function () {
            if (!instance) {
                instance = createInstance();
            }
            return instance;
        }
    };
})();

function run() {

    var instance1 = Singleton.getInstance();
    var instance2 = Singleton.getInstance();

    alert("Same instance? " + (instance1 === instance2));  
}

如何使用IIFE模块模式在javascript中编写单例类？

1 个答案: