函数（导出）returns 一个错误 "Cannot set property 'weekDay' of undefined"

Question

所以我正在阅读 Eloquent JS 书的 'Modules' 章，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));

returns

Cannot set property "weekDay" of undefined

然而，在本书网站上的在线编辑器中，完全相同的代码运行没有问题 return "Monday"。

我想知道是不是 Adobe Brackets 的问题。

Answer 1

使用不依赖于在全局脚本范围内执行的模块模式，其中 this 将是全局对象。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);
        }
    };
}());

所以是的，这是由您的环境造成的，但代码首先是脆弱的。如果你想继续使用那个exports东西，你也可以做

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

或者检查 How to get the global object in JavaScript? and Getting a reference to the global object in an unknown environment in strict mode.

函数（导出）returns 一个错误 "Cannot set property 'weekDay' of undefined"

function(exports) returns an error "Cannot set property 'weekDay' of undefined"

javascript

adobe-brackets