Eloquent Javascript：以下示例中的“this”是什么？

Question

在Objects as interfaces的{​​{1}}部分中查看eloquentjavascript，有一个例子：

（在函数之外，这是指全局范围对象。）

(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(weekDay.number("Saturday")));
// → Saturday

this refers to the global scope object是什么意思？这里的全局范围对象是什么（这个）？困惑。

欢迎任何评论。感谢