[Linux] Javascript设计模式Revealing Module 揭示模式单例模式详解

< script>
var myRevealingModule = function () {
  var privateVar = "Ren Cherry",
      publicVar = "Hey there";
  function privateFunction() {
      console.log("Name:"+privateVar);
  }
  function publicSetName(strName) {
      privateName = strName;
  }
  function publicGetName() {
      privateFunction();
  }
  //将暴露的公有指针指向到私有函数和属性上
  return {
      setName: publicSetName,
      greeting: publicvar,
      getName: publicGetName
  };
}();
myRevealingModule.setName("Paul Kinlan");
< /script>

• 该模式很容易之处哪些函数和变量可被公开访问，改善了可读性。
  

< script type="text/javascript">
var mySingleton = (function () {
    //实例保持了singleton 的一个引用
    var instance;
    function init() {
        //singleton
        //私有方法和变量
        function privateMethod() {
            console.log("I am private");
        }
        var privateVariable = "I am also private";
        var privateRandomNumber = Math.random();
        return {
            //公有方法和变量
            publicMethod: function () {
                console.log("The public can see me!");
            },
            publicProperty: "I am also public",
            getRandomNumber: function() {
                return privateRandomNumber;
            }
        };
    };
    return {
        //获取singleton 的实例，如果存在就返回，不存在就创建新实例
        getInstance: function() {
            if(!instance) {
                instance = init();
            }
            return instance;
        }
    };
})();
var singleA = mySingleton.getInstance();
var singleB = mySingleton.getInstance();
console.log(singleA.getRandomNumber()===singleB.getRandomNumber());//true
< /script>

< script type="text/javascript">
var SingletonTester = (function() {
    //options: 包含singleton所需配置信息的对象
    //var options = {name:"test",pointX:5};
    function Singleton(options) {
        //如果未提供options,则设置为空对象
        options = options || {};
        //为singleton设置一些属性
        this.name = "SingletonTester";
        this.pointX = options.pointX || 6;
        this.pointY = options.pointY || 10;
    }
    //实例持有者
    var instance;
    //静态变量和方法的模拟
    var _static = {
        name: "SingletonTester",
        //获取实例的方法，返回singleton对象的singleton实例
        getInstance: function(options) {
            if(instance === undefined) {
                instance = new Singleton(options);
            }
            return instance;
        };
        return _static;
    }
})();
var singletonTest = SingletonTester.getInstance({
    pointX: 5
});
console.log(singletonTest.pointX);//5
< /script>