javascript - 所有值均替换为 For 循环 TypeScript 中的最后一个值

Question

我在 JavaScript 中有一个 for 循环，它连接 calendarEvents 中的数据:

drop(info) {
    var that = this;
    var startDate = info.date;
    var frequency = this.skippingNumber;

    for (var i = 0; i <= 3; i++) {
      (function (start) {
        that.calendarEvents = that.calendarEvents.concat({
          title: 'Dropped Event',
          start: start,
          allDay: info.allDay
        });
      })(startDate);
      startDate = this.addDays(startDate, frequency);
    }
  }

addDays(date: Date, days: number): Date {
    var passedDate = date;
    passedDate.setDate(passedDate.getDate() + days);
    return passedDate;
  }

如果我在循环内记录startDate，我会得到实际值，即星期一、星期二、星期三、星期四。但是当我记录calendarEvents时，我得到的所有数据都是星期四。谁能帮我这个？预先感谢!

Answer 1

所有 addDays() 调用都接收参数、修改并返回相同的对象 (var startDate = info.date)。

重写addDays()方法来创建并返回一个新的Date对象:

addDays(date: Date, days: number): Date {
    var passedDate = new Date(date.getTime());
    passedDate.setDate(passedDate.getDate() + days);
    return passedDate;
}