1. /**
    2.  * 返回指定长度的天数集合
    3.  * 
    4.  * @param  {time} 时间
    5.  * @param  {len} 长度
    6.  * @param  {direction} 方向： 1: 前几天;  2: 后几天;  3:前后几天  默认 3
    7.  * @return {Array} 数组
    8.  *
    9.  * @example date.getDays('2018-1-29', 6) // -> ["2018-1-26", "2018-1-27", "2018-1-28", "2018-1-29", "2018-1-30", "2018-1-31", "2018-2-1"]
    10.  */
    11. getDays(time, len, diretion) {
    12.   var tt = new Date(time);
    13.   var getDay = function(day) {
    14.       var t = new Date(time);
    15.       t.setDate(t.getDate() + day);
    16.       var m = t.getMonth()+1;
    17.       return t.getFullYear()+'-'+m+'-'+t.getDate();
    18.   }
    19.   var arr = [];
    20.   if (diretion === 1) {
    21.       for (var i = 1; i <= len; i++) {
    22.           arr.unshift(getDay(-i));
    23.       }
    24.   }else if(diretion === 2) {
    25.       for (var i = 1; i <= len; i++) {
    26.           arr.push(getDay(i));
    27.       }
    28.   }else {
    29.       for (var i = 1; i <= len; i++) {
    30.           arr.unshift(getDay(-i));
    31.       }
    32.       arr.push(tt.getFullYear()+'-'+(tt.getMonth()+1)+'-'+tt.getDate());
    33.       for (var i = 1; i <= len; i++) {
    34.           arr.push(getDay(i));
    35.       }
    36.   }
    37.   return diretion === 1 ? arr.concat([tt.getFullYear()+'-'+(tt.getMonth()+1)+'-'+tt.getDate()]) : 
    38.         diretion === 2 ? [tt.getFullYear()+'-'+(tt.getMonth()+1)+'-'+tt.getDate()].concat(arr) : arr
    39. }
    41. /*获取某月有多少天*/
    42. getMonthOfDay (time) {
    43.   var date = new Date(time)
    44.   var year = date.getFullYear()
    45.   var mouth = date.getMonth() + 1
    46.   var days
    47.   //当月份为二月时，根据闰年还是非闰年判断天数
    48.   if (mouth == 2) {
    49.      days = year % 4 == 0 ? 29 : 28
    50.   } else if (mouth == 1 || mouth == 3 || mouth == 5 || mouth == 7 || mouth == 8 || mouth == 10 || mouth == 12) {
    51.      //月份为：1,3,5,7,8,10,12 时，为大月.则天数为31；
    52.      days = 31
    53.   } else {
    54.      //其他月份，天数为：30.
    55.      days = 30
    56.   }
    57.   return days
    58. }
    60. /*获取某年有多少天*/
    61. getYearOfDay (time) {
    62.   var firstDayYear = this.getFirstDayOfYear(time);
    63.   var lastDayYear = this.getLastDayOfYear(time);
    64.   var numSecond = (new Date(lastDayYear).getTime() - new Date(firstDayYear).getTime())/1000;
    65.   return Math.ceil(numSecond/(24*3600));
    66. }
    68. /*获取某年的第一天*/
    69. getFirstDayOfYear (time) {
    70.   var year = new Date(time).getFullYear();
    71.   return year + "-01-01 00:00:00";
    72. }
    74. /*获取某年最后一天*/
    75. getLastDayOfYear (time) {
    76.   var year = new Date(time).getFullYear();
    77.   var dateString = year + "-12-01 00:00:00";
    78.   var endDay = this.getMonthOfDay(dateString);
    79.   return year + "-12-" + endDay + " 23:59:59";
    80. }
    82. /*获取某个日期是当年中的第几天*/
    83. getDayOfYear (time) {
    84.   var firstDayYear = this.getFirstDayOfYear(time);
    85.   var numSecond = (new Date(time).getTime() - new Date(firstDayYear).getTime())/1000;
    86.   return Math.ceil(numSecond/(24*3600));
    87. }
    89. /*获取某个日期在这一年的第几周*/
    90. getDayOfYearWeek (time) {
    91.   var numdays = this.getDayOfYear(time);
    92.   return Math.ceil(numdays / 7);
    93. }