常用工具库—时间函数

前端开发中，常遇到的时间转换方法。

  moment: {
    getMonth: function (strDate) {
      if (!strDate) return ''
      return Number(strDate.substring(4, 6))
    },
    getYear: function (strDate) {
      if (!strDate) return ''
      return Number(strDate.substring(0, 4))
    },
    getDate: function (strDate) {
      if (!strDate) return ''
      return Number(strDate.substring(6))
    },
    // 获得某月的天数
    getMonthDays: function (year, month) {
      if (!year || !month) {
        return 0
      }
      let monthStartDate = new Date(year, month - 1, 1)
      let monthEndDate = new Date(year, month, 1)
      return (monthEndDate - monthStartDate) / (1000 * 60 * 60 * 24)
    },
    /* 获取前一天 */
    getLastDay: function (strDate) {
      if (!strDate) return ''
      let tempDate = new Date(this.getYear(strDate), this.getMonth(strDate) - 1, this.getDate(strDate) - 1)
      return this.date2Str(tempDate)
    },
    /* 获取后一天 */
    getNextDay: function (strDate) {
      if (!strDate) return ''
      let tempDate = new Date(this.getYear(strDate), this.getMonth(strDate) - 1, this.getDate(strDate) + 1)
      return this.date2Str(tempDate)
    },
    /* 获取两个时间段的天数,endTime为空则为当前时间 */
    getBetweenDays: function (startTime, endTime) {
      if (!startTime || !endTime) {
        return ''
      }
      let monthStartDate = Date.UTC(this.getYear(startTime), this.getMonth(startTime) - 1, this.getDate(startTime))
      let monthEndDate = Date.UTC(this.getYear(endTime), this.getMonth(endTime) - 1, this.getDate(endTime))
      return Math.ceil((monthEndDate - monthStartDate) / (1000 * 60 * 60 * 24))
    },
    /* 前一月 */
    getPreviousMonth: function (strTime, format) {
      if (!strTime) return ''
      let year = this.getYear(strTime)
      let month = this.getMonth(strTime)
      let day = strTime.substring(6)
      if (month - 1 === 0) {
        year--
        month = 12
      } else {
        month--
      }
      month = month > 9 ? month : '0' + month
      let result = year + '' + month + '' + day
      if (format) {
        result = this._format(format, year, month, day)
      }
      return result
    },
    _format: function (format, year, month, day) {
      return format.replace('YYYY', year).replace('YY', (year + '').substr(-2)).replace('MM', month).replace('M', Number(month)).replace('DD', day).replace('D', Number(day))
    },
    /* 下一月 */
    getNextMonth: function (strTime, format) {
      if (!strTime) return ''
      let year = this.getYear(strTime)
      let month = this.getMonth(strTime)
      let day = strTime.substring(6)
      month++
      if (month === 13) {
        year++
        month = 1
      }
      month = month > 9 ? month : '0' + month
      let result = year + '' + month + '' + day
      if (format) {
        result = this._format(format, year, month, day)
      }
      return result
    },

    /* 加多少个月 */
    addMonth: function (strTime, months, format) {
      if (!strTime) return ''
      let tempDate = new Date(this.transformDate(strTime, 'YYYY/MM/DD'))
      tempDate.setMonth(tempDate.getMonth() + Number(months))
      if (!format) {
        return this.date2Str(tempDate)
      } else {
        let month = tempDate.getMonth() + 1
        month = month > 9 ? month : '0' + month
        let date = tempDate.getDate()
        date = date > 9 ? date : '0' + date
        return this._format(format, tempDate.getFullYear(), month, date)
      }
    },

    /* 日期格式 */
    transformDate: function (strTime, format) {
      if (!strTime || !format) return ''
      let year = strTime.substring(0, 4)
      let month = strTime.substring(4, 6)
      let day = strTime.substring(6)
      return this._format(format, year, month, day)
    },

    /* 获取当前的年月日==>20161130 */
    getCurrDate: function () {
      return this.date2Str(new Date())
    },
    /* 日期转字符串：==>20161130 */
    date2Str: function (dateInfo) {
      if (!dateInfo) return ''
      if (dateInfo instanceof Date) {
        let month = dateInfo.getMonth() + 1
        month = month > 9 ? month : '0' + month
        let date = dateInfo.getDate()
        date = date > 9 ? date : '0' + date
        return dateInfo.getFullYear() + '' + month + date
      }
    },
    /* 格式化时间 YYYY-MM-DD hh:mm:ss */
    formatTime: function (timestamp, format) {
      let date = new Date(timestamp)
      let year = date.getFullYear()
      let month = date.getMonth() + 1
      month = month > 9 ? month : '0' + month
      let day = date.getDate()
      day = day > 9 ? day : '0' + day
      let hours = date.getHours()
      hours = hours > 9 ? hours : '0' + hours
      let minutes = date.getMinutes()
      minutes = minutes > 9 ? minutes : '0' + minutes
      let seconds = date.getSeconds()
      seconds = seconds > 9 ? seconds : '0' + seconds
      let result = this._format(format, year, month, day)
      return result.replace('hh', hours).replace('mm', minutes).replace('ss', seconds)
    }
  },