Learning Javascript OOP II

function foo() {
   var i = 2;

   // private function
   function bar() {
      i *= 2;
   }

   bar();
   return i;
}

 

function foo() {
   var i = 2;

   // private function
   function bar() {
      i *= 2;
      return i;
   }

   return bar();
}
var baz = foo(); // baz is now a reference to function bar.
baz(); // returns 4
baz(); // returns 8
baz(); // returns 16

var blat = foo(); // blat is another reference to bar.
blat(); // return 4
 

var Persion = function(name, age) {
   var name;
   
   this.setName(nameParam) {
      name = nameParam;
   }
}

var Person = function(name, age) {
   var name;
   var age;

   this.getName() {
      return name;
   }

   this.getAge() {
      return age;
   }

};

Person.prototype = function() {
   toString : function() {
      return this.getName() + " is " + this.getAge() + " years old."
   }
}

var Person = (function(){
   
   // const variable(This variable won't be changed, so it's final.)
   var EIGHTEEN = 18;

   // private static variable
   var personCount = 0;

   // private static method
   function isAdult(age) {
      return age >= EIGHTEEN ? true : false;
   }

   // constructor
   return function(nameParam, ageParam) {
      // private instance variable
      var name, age;

      // public instance method(Privileged method)
      this.setName = function(nameParam) {
         name = nameParam;
      };
      this.getName = function() {
         return name;
      };
      this.setAge = function(ageParam) {
         if (isAdult(ageParam)) {
            age = ageParam;
         }
         age = EIGHTEEN;
      };
      this.getAge = function() {
         return age;
      };

      // init properties or do some about initializing work
      personCount++;

      this.setName(nameParam);
      this.setAge(ageParam);
   }
})();

// public static method for Person class
Person.doSomething = function() {
   //TODO......
};

// Create Person instance
Person handy_wang = new Person("handy.wang", 18);
handy_wang.setName("Wang-Jiangshan");
handy_wang.setAge(24);
Person.doSomething();