Javascript模块模式/原型模式:找不出这段代码

Question

我试图创建一个简单的谷歌地图插件。我正在学习一个教程，但我无法理解这段代码。有人能解释我的密码吗？

(function(window, google) {

   var Mapster = (function() {
       function Mapster(element, opts) {
           this.gMap = new google.maps.Map(element,opts);
       }

       Mapster.prototype = {
           zoom: function(level) {
               //some code here
           }
       };

       return Mapster;
   }());

  Mapster.create = function(element, opts) {
      return new Mapster(element, opts);
 };

 window.Mapster = Mapster;

}(window, google));

Answer 1

// http://benalman.com/news/2010/11/immediately-invoked-function-expression/
(function (window, google) {
    // local `Mapster` IIFE
    var Mapster = (function () {
        // local `Mapster` constructor function
        function Mapster(element, opts) {
            this.gMap = new google.maps.Map(element, opts);
        }

        Mapster.prototype = {
            zoom: function (level) {
                //some code here
            }
        };

        return Mapster;
    }());

    // convenience function to create new instances of `Mapster`
    Mapster.create = function (element, opts) {
        return new Mapster(element, opts);
    };

    // exposing `Mapster` globally
    window.Mapster = Mapster;

    // passing in `window` & `google` as params to the IIFE
}(window, google));

// usage:

var mapster = Mapster.create(someEl, {});

console.log(mapster.gMap);

希望这些评论能澄清这一点！