js深入研究之牛逼的类封装设计

<script type="text/javascript">
var Book = function(newIsbn, newTitle, newAuthor) { // implements Publication

  // 私有属性
  var isbn, title, author;

  // 私有方法
  function checkIsbn(isbn) {
    if(isbn == undefined || typeof isbn != 'string') {
      return false;
    }
    return true; // All tests passed.
  }  

  // 特权方法
  this.getIsbn = function() {
    return isbn;
  };
  this.setIsbn = function(newIsbn) {
    if(!checkIsbn(newIsbn)) throw new Error('Book: Invalid ISBN.');
    isbn = newIsbn;
  };

  this.getTitle = function() {
    return title;
  };
  this.setTitle = function(newTitle) {
    title = newTitle || 'No title specified';
  };

  this.getAuthor = function() {
    return author;
  };
  this.setAuthor = function(newAuthor) {
    author = newAuthor || 'No author specified';
  };

  // 构造代码
  this.setIsbn(newIsbn);
  this.setTitle(newTitle);
  this.setAuthor(newAuthor);
};

// Public, non-privileged methods.
Book.prototype = {
  display: function() {
    alert("isbn:"+this.getIsbn()+" title:"+this.getTitle()+" author:"+this.getAuthor());
  }
};

//var theHobbit = new Book(123, '', 'J. R. R. Tolkein'); // 非字符串抛出异常
var theHobbit = new Book('1990-78sd-1092', '', 'J. R. R. Tolkein'); 
theHobbit.display(); // Outputs the data by creating and populating an HTML element.


</script>

必须通过get方法来获取数据，因为数据是私有的。

js设计模式太牛逼了。