无法实现模块模式 [英] Unable to implement module pattern

问题描述

我想从Douglas Crockford的书Javascript：The Good Parts中重现一些代码。这个想法是使用闭包对象封装，并避免JavaScript的内在全局变量。

  var serial_maker = function（）{
 
 //生成一个生成唯一字符串的对象。 A 
 //唯一字符串由两部分组成：前缀
 //和序列号。该对象带有
 //方法用于设置前缀和序列
 // number，以及gensym方法生成唯一的
 //字符串。 
 
 var prefix =''; 
 var seq = 0; 
 return {
 set_prefix：function（p）{
 prefix = String（p）; 
}，
 set_seq：function（s）{
 seq = s; 
}，
 gensym：function（）{
 var result = prefix + seq; 
 seq + = 1; 
 return result; 
} 
}; 
}（）; 
 
 var seqer = serial_maker（）; 
 seqer.set_prefix ='Q'; 
 seqer.set_seq = 1000; 
 var unique = seqer.gensym（）; // unique isQ1000
  

Chrome收到错误：

未捕获的TypeError：属性
'serial_maker'的对象[object
DOMWindow]不是函数
（匿名函数） p>

我做错了什么？

编辑：我应该说这段代码完全从书中复制和粘贴...

解决方案

您试图将函数的结果作为函数执行，正在为函数分配值。
Try：

  var seqer = serial_maker; 
 seqer.set_prefix（'Q'）; 
 seqer.set_seq（1000）; 
 var unique = seqer.gensym（）; 
  

另请参阅 jsFiddle

I am trying to reproduce some code from the book "Javascript: The Good Parts" by Douglas Crockford. The idea is to use closures for object encapsulation and avoid Javascript's inherent global variables.

var serial_maker = function (  ) {

// Produce an object that produces unique strings. A
// unique string is made up of two parts: a prefix
// and a sequence number. The object comes with
// methods for setting the prefix and sequence
// number, and a gensym method that produces unique
// strings.

    var prefix = '';
    var seq = 0;
    return {
        set_prefix: function (p) {
            prefix = String(p);
        },
        set_seq: function (s) {
            seq = s;
        },
        gensym: function (  ) {
            var result = prefix + seq;
            seq += 1;
            return result;
        }
    };
}(  );

var seqer = serial_maker(  );
seqer.set_prefix = 'Q';
seqer.set_seq = 1000;
var unique = seqer.gensym(  );    // unique is "Q1000"

Chrome is picking up the error:

Uncaught TypeError: Property 'serial_maker' of object [object DOMWindow] is not a function (anonymous function)

What am I doing wrong?

EDIT: I should say this code is entirely copy and pasted from the book...

解决方案

You are trying to execute the result of a function as a function, and are assigning values to functions. Try:

var seqer = serial_maker;
seqer.set_prefix('Q');
seqer.set_seq(1000);
var unique = seqer.gensym();

Also see this jsFiddle

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