Detailed explanation of javaScript date tool class DateUtils

DateUtils = {

    patterns: {

      PATTERN_ERA: 'G', //Era 标志符 Era strings. For example: "AD" and "BC"

      PATTERN_YEAR: 'y', //年

      PATTERN_MONTH: 'M', //月份

      PATTERN_DAY_OF_MONTH: 'd', //月份的天数

      PATTERN_HOUR_OF_DAY1: 'k', //一天中的小时数（1-24）

      PATTERN_HOUR_OF_DAY0: 'H', //24小时制，一天中的小时数（0-23）

      PATTERN_MINUTE: 'm', //小时中的分钟数

      PATTERN_SECOND: 's', //秒

      PATTERN_MILLISECOND: 'S', //毫秒

      PATTERN_DAY_OF_WEEK: 'E', //一周中对应的星期，如星期一，周一

      PATTERN_DAY_OF_YEAR: 'D', //一年中的第几天

      PATTERN_DAY_OF_WEEK_IN_MONTH: 'F', //一月中的第几个星期(会把这个月总共过的天数除以7,不够准确，推荐用W)

      PATTERN_WEEK_OF_YEAR: 'w', //一年中的第几个星期

      PATTERN_WEEK_OF_MONTH: 'W', //一月中的第几星期(会根据实际情况来算)

      PATTERN_AM_PM: 'a', //上下午标识

      PATTERN_HOUR1: 'h', //12小时制 ，am/pm 中的小时数（1-12）

      PATTERN_HOUR0: 'K', //和h类型

      PATTERN_ZONE_NAME: 'z', //时区名

      PATTERN_ZONE_VALUE: 'Z', //时区值

      PATTERN_WEEK_YEAR: 'Y', //和y类型

      PATTERN_ISO_DAY_OF_WEEK: 'u',

      PATTERN_ISO_ZONE: 'X'

    },

    week: {

      'ch': {

        "0": "\u65e5",

        "1": "\u4e00",

        "2": "\u4e8c",

        "3": "\u4e09",

        "4": "\u56db",

        "5": "\u4e94",

        "6": "\u516d"

      },

      'en': {

        "0": "Sunday",

        "1": "Monday",

        "2": "Tuesday",

        "3": "Wednesday",

        "4": "Thursday",

        "5": "Friday",

        "6": "Saturday"

      }

    },

    //获取当前时间

    getCurrentTime: function() {

      var today = new Date();

      var year = today.getFullYear();

      var month = today.getMonth() + 1;

      var day = today.getDate();

      var hours = today.getHours();

      var minutes = today.getMinutes();

      var seconds = today.getSeconds();

      var timeString = year + "-" + month + "-" + day + " " + hours + ":" + minutes + ":" + seconds;

      return timeString;

    },

    /*

     * 比较时间大小

     * time1>time2 return 1

     * time1<time2 return -1

     * time1==time2 return 0

     */

    compareTime: function(time1, time2) {

      if(Date.parse(time1.replace(/-/g, "/")) > Date.parse(time2.replace(/-/g, "/"))) {

        return 1;

      } else if(Date.parse(time1.replace(/-/g, "/")) < Date.parse(time2.replace(/-/g, "/"))) {

        return -1;

      } else if(Date.parse(time1.replace(/-/g, "/")) == Date.parse(time2.replace(/-/g, "/"))) {

        return 0;

      }

    },

    //是否闰年

    isLeapYear: function(year) {

      return((year % 4 === 0 && year % 100 !== 0) || year % 400 === 0);

    },

    //获取某个月的天数，从0开始

    getDaysOfMonth: function(year, month) {

      return [31, (this.isLeapYear(year) ? 29 : 28), 31, 30, 31, 30, 31, 31, 30, 31, 30, 31][month];

    },

    getDaysOfMonth2: function(year, month) {

      // 将天置为0，会获取其上个月的最后一天

      month = parseInt(month) + 1;

      var date = new Date(year, month, 0);

      return date.getDate();

    },

    /*距离现在几天的日期：负数表示今天之前的日期，0表示今天，整数表示未来的日期

     * 如-1表示昨天的日期，0表示今天，2表示后天

     */

    fromToday: function(days) {

      var today = new Date();

      today.setDate(today.getDate() + days);

      var date = today.getFullYear() + "-" + (today.getMonth() + 1) + "-" + today.getDate();

      return date;

    },

    /**

     * 日期时间格式化

     * @param {Object} dateTime 需要格式化的日期时间

     * @param {String} pattern 格式化的模式，如yyyy-MM-dd hh(HH):mm:ss.S a k K E D F w W z Z

     */

    formt: function(dateTime, pattern) {

      var date = new Date(dateTime);

      if(Bee.StringUtils.isBlank(pattern)) {

        return date.toLocaleString();

      }

      return pattern.replace(/([a-z])\1*/ig, function(matchStr, group1) {

        var replacement = "";

        switch(group1) {

          case Bee.DateUtils.patterns.PATTERN_ERA: //G

            break;

          case Bee.DateUtils.patterns.PATTERN_WEEK_YEAR: //Y

          case Bee.DateUtils.patterns.PATTERN_YEAR: //y

            replacement = date.getFullYear();

            break;

          case Bee.DateUtils.patterns.PATTERN_MONTH: //M

            var month = date.getMonth() + 1;

            replacement = (month < 10 && matchStr.length >= 2) ? "0" + month : month;

            break;

          case Bee.DateUtils.patterns.PATTERN_DAY_OF_MONTH: //d

            var days = date.getDate();

            replacement = (days < 10 && matchStr.length >= 2) ? "0" + days : days;

            break;

          case Bee.DateUtils.patterns.PATTERN_HOUR_OF_DAY1: //k(1~24)

            var hours24 = date.getHours();

            replacement = hours24;

            break;

          case Bee.DateUtils.patterns.PATTERN_HOUR_OF_DAY0: //H(0~23)

            var hours24 = date.getHours();

            replacement = (hours24 < 10 && matchStr.length >= 2) ? "0" + hours24 : hours24;

            break;

          case Bee.DateUtils.patterns.PATTERN_MINUTE: //m

            var minutes = date.getMinutes();

            replacement = (minutes < 10 && matchStr.length >= 2) ? "0" + minutes : minutes;

            break;

          case Bee.DateUtils.patterns.PATTERN_SECOND: //s

            var seconds = date.getSeconds();

            replacement = (seconds < 10 && matchStr.length >= 2) ? "0" + seconds : seconds;

            break;

          case Bee.DateUtils.patterns.PATTERN_MILLISECOND: //S

            var milliSeconds = date.getMilliseconds();

            replacement = milliSeconds;

            break;

          case Bee.DateUtils.patterns.PATTERN_DAY_OF_WEEK: //E

            var day = date.getDay();

            replacement = Bee.DateUtils.week['ch'][day];

            break;

          case Bee.DateUtils.patterns.PATTERN_DAY_OF_YEAR: //D

            replacement = Bee.DateUtils.dayOfTheYear(date);

            break;

          case Bee.DateUtils.patterns.PATTERN_DAY_OF_WEEK_IN_MONTH: //F

            var days = date.getDate();

            replacement = Math.floor(days / 7);

            break;

          case Bee.DateUtils.patterns.PATTERN_WEEK_OF_YEAR: //w

            var days = Bee.DateUtils.dayOfTheYear(date);

            replacement = Math.ceil(days / 7);

            break;

          case Bee.DateUtils.patterns.PATTERN_WEEK_OF_MONTH: //W

            var days = date.getDate();

            replacement = Math.ceil(days / 7);

            break;

          case Bee.DateUtils.patterns.PATTERN_AM_PM: //a

            var hours24 = date.getHours();

            replacement = hours24 < 12 ? "\u4e0a\u5348" : "\u4e0b\u5348";

            break;

          case Bee.DateUtils.patterns.PATTERN_HOUR1: //h(1~12)

            var hours12 = date.getHours() % 12 || 12; //0转为12

            replacement = (hours12 < 10 && matchStr.length >= 2) ? "0" + hours12 : hours12;

            break;

          case Bee.DateUtils.patterns.PATTERN_HOUR0: //K(0~11)

            var hours12 = date.getHours() % 12;

            replacement = hours12;

            break;

          case Bee.DateUtils.patterns.PATTERN_ZONE_NAME: //z

            replacement = Bee.DateUtils.getZoneNameValue(date)['name'];

            break;

          case Bee.DateUtils.patterns.PATTERN_ZONE_VALUE: //Z

            replacement = Bee.DateUtils.getZoneNameValue(date)['value'];

            break;

          case Bee.DateUtils.patterns.PATTERN_ISO_DAY_OF_WEEK: //u

            break;

          case Bee.DateUtils.patterns.PATTERN_ISO_ZONE: //X

            break;

          default:

            break;

        }

        return replacement;

      });

    },

    /**

     * 计算一个日期是当年的第几天

     * @param {Object} date

     */

    dayOfTheYear: function(date) {

      var obj = new Date(date);

      var year = obj.getFullYear();

      var month = obj.getMonth(); //从0开始

      var days = obj.getDate();

      var daysArr = [31, (this.isLeapYear(year) ? 29 : 28), 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];

      for(var i = 0; i < month; i++) {

        days += daysArr[i];

      }

      return days;

    },

    //获得时区名和值

    getZoneNameValue: function(dateObj) {

      var date = new Date(dateObj);

      date = new Date(Date.UTC(date.getFullYear(), date.getMonth(), date.getDate()));

      var arr = date.toString().match(/([A-Z]+)([-+]\d+:?\d+)/);

      var obj = {

        'name': arr[1],

        'value': arr[2]

      };

      return obj;

    }

  };