code: function getYearWeek (date) {
    date = toStringDate(date)
    if (baseExports.isDate(date)) {
      date.setHours(0, 0, 0, 0)
      date.setDate(date.getDate() + 3 - (date.getDay() + 6) % 7)
      var week = new Date(date.getFullYear(), 0, 4)
      return Math.round(((date.getTime() - week.getTime()) / DAY_TIME + (week.getDay() + 6) % 7 - 3) / 7) + 1
    }
    return date
  }
docs: 返回某个年份的第几周
  
  @param {Date} date 日期或数字
  @return {Number}