Question

所以我要经历一个＆＃39; Modules＆＃39; Eloquent JS书的章节和我遇到了函数（导出）部分的问题。

(function (exports) {
var names = ["Sunday", "Monday", "Tuesday", "Wednesday",
           "Thursday", "Friday", "Saturday"];

exports.name = function (number) {
    return names[number];
};
exports.number = function (name) {
    return names.indexOf(name);
};
})(this.weekDay = {});

console.log(weekDay.name(1));

返回

Cannot set property "weekDay" of undefined

然而，在本书网站的在线编辑器中，完全相同的代码运行没有问题并返回＆＃34;星期一＆＃34;。

我想知道Adobe Brackets是否存在问题。

Answer 1

使用不依赖于在this作为全局对象的全局脚本范围中执行的模块模式。我推荐

var weekDay = (function (exports) {
    var names = ["Sunday", "Monday", "Tuesday", "Wednesday",
               "Thursday", "Friday", "Saturday"];
    return {
        name: function (number) {
            return names[number];
        },
        number: function (name) {
            return names.indexOf(name);
        }
    };
}());

是的，这是由您的环境引起的，但代码首先是脆弱的。如果你想继续使用那个exports的东西，你也可以

var weekDay;
(function (exports) {
    …
})(weekDay = {});

或者选中How to get the global object in JavaScript?和Getting a reference to the global object in an unknown environment in strict mode。

function（exports）返回错误＆＃34;无法设置属性＆quot; weekDay＆＃39;未定义＆＃34;

1 个答案: