减少没有初始值的空数组

时间:2019-06-14 10:31:19

标签: javascript reactjs fullcalendar

我正在使用fullcalendar-react,并且我有以下时间表,我在该时间表中尝试获取列表的最早时间,并删除关闭日期:

export default {
    monday: {
        startTime: '10:00',
        endTime: '23:00'
    },
    tuesday: {
        startTime: '08:00',
        endTime: '00:00'
    },
    wednesday: {
        startTime: '09:00',
        endTime: '22:00'
    },
    thursday: {
        startTime: '14:00',
        endTime: '00:00'
    },
    friday: undefined,
    saturday: {
        startTime: '13:00',
        endTime: '21:00'
    },
    sunday: undefined
}

要过滤关闭的日期并获得最早的时间,我正在处理filter和reduce,如下所示:

getOpeningHour() {
    let value: any = "00:00:00";

    if (this.props.schedule) {
        const schedule = this.props.schedule; // the schedule I presented above

        if (Object.keys(schedule).length >= 1) {
            const minValue = Object.keys(schedule)
                .filter((key) => schedule[key])
                .map((key: string) => moment(schedule[key].startTime, 'HH:mm'))
                .reduce((min: moment.Moment, value: moment.Moment) => (!min || value.isBefore(min) ? value : min), moment('00:00', 'HH:mm')); 
                // Gets the earliest hour when the list is not empty, but when I give midnight as default value, it's always midnight.

            value = minValue.format('HH:mm:ss');
        }
    }
    return value;
}

打开日历时,出现此错误:

  

未捕获的TypeError:减少没有初始值的空数组

当列表为空时,我尝试提供, moment('00:00', 'HH:mm')作为默认值,但我想,这样,我的日历总是从午夜开始,而忽略其余时间。

-----编辑-----

代码实际上正在工作,并且由于午夜早于08:00,因此它将显示午夜。唯一的事情是仅在列表为空时显示午夜。

当我使用moment()小时时,如何解决此问题? 谢谢!

1 个答案:

答案 0 :(得分:2)

尝试moment('24:00', 'HH:mm')

const hourTemplate = 'HH:mm';

const getEarliersHour = schedule =>
  Object.values(schedule)
    .filter(value => value)                  // no undefined
    .map(time => moment(time.startTime, hourTemplate))
    .reduce(
      (min, curr) => (curr.isBefore(min) ? curr : min),
      moment('24:00', hourTemplate)         // latest moment
    )
    .format(hourTemplate);

getEarliersHour(schedule);                  // 08:00
getEarliersHour({});                        // 00:00

演示:

Edit cold-sunset-oc7fy