Example analysis of JS anonymous function class generation method

The example in this article describes how to generate JS anonymous function classes. Share it with everyone for your reference, the details are as follows:

<script type="text/javascript">
var Book = (function() {
 // 私有静态属性
 var numOfBooks = 0;
 // 私有静态方法
 function checkIsbn(isbn) {
  if(isbn == undefined || typeof isbn != &#39;string&#39;) {
   return false;
  }
  return true;
 }
 // 返回构造函数
 return function(newIsbn, newTitle, newAuthor) { // implements Publication
  // 私有属性
  var isbn, title, author;
  // 特权方法
  this.getIsbn = function() {
   return isbn;
  };
  this.setIsbn = function(newIsbn) {
   if(!checkIsbn(newIsbn)) throw new Error(&#39;Book: Invalid ISBN.&#39;);
   isbn = newIsbn;
  };
  this.getTitle = function() {
   return title;
  };
  this.setTitle = function(newTitle) {
   title = newTitle || &#39;No title specified&#39;;
  };
  this.getAuthor = function() {
   return author;
  };
  this.setAuthor = function(newAuthor) {
   author = newAuthor || &#39;No author specified&#39;;
  };
  // 控制对象数目，构造函数
  numOfBooks++; // Keep track of how many Books have been instantiated
         // with the private static attribute.
  if(numOfBooks > 5) throw new Error(&#39;Book: Only 5 instances of Book can be &#39;
    + &#39;created.&#39;);
  this.setIsbn(newIsbn);
  this.setTitle(newTitle);
  this.setAuthor(newAuthor);
 }
})();
// 公有静态方法
Book.convertToTitleCase = function(inputString) {
 alert(&#39;convertToTitleCase&#39;);
};
// 公有非特权方法
Book.prototype = {
 display: function() {
  alert("isbn:"+this.getIsbn()+" title:"+this.getTitle()+" author:"+this.getAuthor());
 }
};
//var theHobbit = new Book(123, &#39;&#39;, &#39;J. R. R. Tolkein&#39;); // 非字符串抛出异常
var theHobbit = new Book(&#39;1990-78sd-1092&#39;, &#39;&#39;, &#39;J. R. R. Tolkein&#39;);
theHobbit.display();
//theHobbit.convertToTitleCase(); // Uncaught TypeError: Object #<Object> has no method &#39;convertToTitleCase&#39;
Book.convertToTitleCase(); // 输出convertToTitleCase
var theHobbit2 = new Book(&#39;1990-78sd-1092&#39;, &#39;&#39;, &#39;J. R. R. Tolkein&#39;);
theHobbit2.display();
var theHobbit3 = new Book(&#39;1990-78sd-1092&#39;, &#39;&#39;, &#39;J. R. R. Tolkein&#39;);
theHobbit3.display();
var theHobbit4 = new Book(&#39;1990-78sd-1092&#39;, &#39;&#39;, &#39;J. R. R. Tolkein&#39;);
theHobbit4.display();
var theHobbit5 = new Book(&#39;1990-78sd-1092&#39;, &#39;&#39;, &#39;J. R. R. Tolkein&#39;);
theHobbit5.display();
var theHobbit6 = new Book(&#39;1990-78sd-1092&#39;, &#39;&#39;, &#39;J. R. R. Tolkein&#39;);
theHobbit6.display(); // Uncaught Error: Book: Only 5 instances of Book can be created.
</script>

JS has been mastered here, I admire it to the extreme, the code is clear, concise, beautiful, and the comments are just right.