无法实现模块模式

Question

我试图重现Douglas Crockford所着的"Javascript:The Good Parts"一书中的一些代码.我们的想法是使用闭包进行对象封装,避免使用Javascript固有的全局变量.

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正在接收错误:

未捕获的TypeError:对象[对象DOMWindow]的属性'serial_maker'不是函数(匿名函数)

我究竟做错了什么？

编辑:我应该说这段代码完全是从书中复制和粘贴的......

Answer 1

您正在尝试将函数的结果作为函数执行,并将值赋给函数.尝试:

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

也看到这个jsFiddle