initialize myObject by calling a function that returns an object literal

w作用域控制变量的可见范围。

JavaScript: The Good Parts

Instead of initializing myObject with an object literal, we will initialize myObject by calling a function that returns an object literal. That function defines a value variable. That variable is always available to the increment and getValue methods, but the function's scope keeps it hidden from the rest of the program

 <script type="text/javascript">
     var wObject = function () {
         var value = 0;
         return {
             increment: function (inc) {
                 value += typeof inc === 'number' ? inc : 1;
             },
             getValue: function () {
                 return value;
             }
         }
     }();
     wf(wObject)
     function wf(w) {
         console.log(w)
     }

     wf(wObject.increment(3))
     wf(wObject.getValue())
     wf(wObject.increment(3))
     wf(wObject.getValue())

     var wObject = function () {
         var value = 0;
         return {
             increment: function (inc) {
                 value += typeof inc === 'number' ? inc : 1;
                 return 'www';
             },
             getValue: function () {
                 return value;
             }
         }
     }();
     wf(wObject)
     function wf(w) {
         console.log(w)
     }

     wf(wObject.increment(3))
     wf(wObject.getValue())
     wf(wObject.increment(3))
     wf(wObject.getValue())
 </script>