js日期格式化器，format,parse

js日期格式化器，format,parse

//字符串格式化为固定长度，默认将占位符补到右侧//@param {string} str 源字符串//@param {int} length 固定长度//@param {string} place 占位符，默认为 "0"//@param {boolean} left 是否将占位符补到字符串左侧var fix = function(str,length,place,left){if (typeof str !== 'string') {return str;};length = length || 0;if (str.length >= length) {return str;};place = place || '0';var len = length - str.length,times = Math.floor(len / place.length),arr = [];for (var i = 0; i < times; i++) {arr.push(place);};if (left) {if (str.length + arr.length < length) {arr.push(place.substr(0,str.length - length));};str = arr.join('') + str;}else{str += arr.join('');if (str.length < length) {str += place.substr(0,str.length - length);};}return str;};//月份全称var MONTHNAMES = ['January','February','March','April','May','June','July','August','September','October','November','December'];

/*将日期格式的对象格式化为字符串，如果不提供格式化器，将采用系统默认的Date.toString@see https://msdn.microsoft.com/zh-cn/library/8kb3ddd4(v=vs.100).aspx@warning 采用format格式化的日期字符串，如果还需要parse为日期格式，请使用完全格式化器，否则将导致解析失败For example:推荐 ：format(new Date(),'yyyy-MM-dd HH:mm:ss.fff')错误 ：format(new Date(),'yyyy-M-d H:m:s.f')，简化的格式化器转化出的字符串无法再被正确的parse格式说明符                  说明                              示例"d"             一个月中的某一天（1 到 31）。           6/1/2009 1:45:30 PM -> 1                                                                6/15/2009 1:45:30 PM -> 15        "dd"            一个月中的某一天（01 到 31）。          6/1/2009 1:45:30 PM -> 016/15/2009 1:45:30 PM -> 15"f"             日期和时间值的十分之几秒。              6/15/2009 13:45:30.617 -> 66/15/2009 13:45:30.050 -> 0"ff"            日期和时间值的百分之几秒。6/15/2009 13:45:30.617 -> 616/15/2009 13:45:30.005 -> 00"fff"     日期和时间值的毫秒。6/15/2009 13:45:30.617 -> 6176/15/2009 13:45:30.0005 -> 000"h"采用 12 小时制的小时（从 1 到 12）。6/15/2009 1:45:30 AM -> 16/15/2009 1:45:30 PM -> 1"hh"采用 12 小时制的小时（从 01 到 12）。6/15/2009 1:45:30 AM -> 016/15/2009 1:45:30 PM -> 01"H"采用 24 小时制的小时（从 0 到 23）。6/15/2009 1:45:30 AM -> 16/15/2009 1:45:30 PM -> 13"HH"采用 24 小时制的小时（从 00 到 23）。6/15/2009 1:45:30 AM -> 016/15/2009 1:45:30 PM -> 13"m"分钟（0 到 59）。6/15/2009 1:09:30 AM -> 96/15/2009 1:09:30 PM -> 9"mm"分钟（00 到 59）。6/15/2009 1:09:30 AM -> 096/15/2009 1:09:30 PM -> 09"M"月份（1 到 12）。6/15/2009 1:45:30 PM -> 6"MM"月份（01 到 12）。6/15/2009 1:45:30 PM -> 06"MMM"月份的缩写名称。6/15/2009 1:45:30 PM -> Jun"MMMM"月份的完整名称。6/15/2009 1:45:30 PM -> June"s"秒（0 到 59）。6/15/2009 1:45:09 PM -> 9"ss"秒（00 到 59）。6/15/2009 1:45:09 PM -> 09"t"AM/PM 指示符的第一个字符。6/15/2009 1:45:30 PM -> P"tt"AM/PM 指示符。                          6/15/2009 1:45:30 PM -> PM"y"年份（0 到 99）。6/15/2009 1:45:30 PM -> 9"yy"年份（00 到 99）。1/1/1900 12:00:00 AM -> 006/15/2009 1:45:30 PM -> 09"yyy"年份（最少三位数字）。1/1/0900 12:00:00 AM -> 9001/1/1900 12:00:00 AM -> 19006/15/2009 1:45:30 PM -> 2009"yyyy"由四位数字表示的年份。6/15/2009 1:45:30 PM -> 2009"z"相对于 UTC 的小时偏移量，无前导零。6/15/2009 1:45:30 PM -07:00 -> -7"zz"相对于 UTC 的小时偏移量，带有表示一6/15/2009 1:45:30 PM -07:00 -> -07位数值的前导零。"g"公元纪年6/15/0600 1:45:30 PM -07:00 -> -76/15/2009 1:45:30 PM -07:00 -> -21"gg"公元纪年（有前导0）6/15/0600 1:45:30 PM -07:00 -> -076/15/2009 1:45:30 PM -07:00 -> -21*///@param {Date} date 要格式化的日期//@param {string} frm 格式化的字符串占位符var format = function(date,frm){if (!(date instanceof Date)) {return date;};if (!frm) {return date.toString();};var year = Math.abs(date.getFullYear()),n = date.getFullYear() < 0 ? '-' : '',offset = date.getTimezoneOffset() / 60,yearStr = n + fix(year.toString(),4,'0',true),y = parseInt(yearStr.substr(yearStr.length - 2)),month = date.getMonth() + 1,d = date.getDate(),H = date.getHours(),h = H != 12 ? H % 12 : H,m = date.getMinutes(),s = date.getSeconds(),f = date.getMilliseconds(),g = year % 100 == 0 ? (year / 100 + 1) : Math.ceil(year / 100);return frm.replace(/y+/g,function(match){var z = year < 0 ? '-' : '';switch(match.length){case 1:return y;case 2:return n+fix(y.toString(),2,'0',true);default:return n+fix(year.toString(),match.length,'0',true);}}).replace(/d{1,2}/g,function(match){if (match.length == 1) {return d;}return fix(d.toString(),match.length,'0',true);}).replace(/h{1,2}/g,function(match){if (match.length == 1) {return h;}return fix(h.toString(),match.length,'0',true);}).replace(/H{1,2}/g,function(match){if (match.length == 1) {return H;}return fix(H.toString(),match.length,'0',true);}).replace(/H{1,2}/g,function(match){if (match.length == 1) {return H;}return fix(H.toString(),match.length,'0',true);}).replace(/m{1,2}/g,function(match){if (match.length == 1) {return m;}return fix(m.toString(),match.length,'0',true);}).replace(/s{1,2}/g,function(match){if (match.length == 1) {return s;}return fix(s.toString(),match.length,'0',true);}).replace(/f+/g,function(match){var ms = f.toString();if (ms.length > match.length) {return ms.substr(0,match.length);};return fix(ms.toString(),match.length,'0',true);}).replace(/g{1,2}/g,function(match){if (match.length == 1) {return g;}return n+fix(g.toString(),match.length,'0',true);}).replace(/z{1,2}/g,function(match){if (match.length == 1) {return offset;}return (offset < 0 ? '-' : '') + fix(Math.abs(offset).toString(),match.length,'0',true);}).replace(/t{1,2}/g,function(match){if (match.length == 1) {return H >= 12 ? 'P' : 'A';}return H >= 12 ? 'P{#}' : 'A{#}';}).replace(/M{1,4}/g,function(match){switch(match.length){case 1:return month;case 2:return fix(month.toString(),match.length,'0',true);default:var M = MONTHNAMES[month-1];return match.length < 4 ? M.substr(0,3) : M;}}).replace(/\{\#\}/g,'M');};

/*将字符串转换为日期格式，如果未提供格式化器，则采用系统默认的Date.parse格式化器见format@param {string} dateStr 字符串形式的日期@param {string} frm 自定义的日期格式化器@example 日期字符串格式化器'2015-11-23 16:30:25.506''yyyy-MM-dd HH:mm:ss.fff''-03世纪 -0200年December月01日 00时00分00秒000毫秒 AM -08''gg世纪 yyyy年MMMM月dd日 hh时mm分ss秒fff毫秒 tt zz'*/var parse = function(dateStr,frm){if (!dateStr) {return null;};if (!frm) {return new Date(Date.parse(dateStr));};var place,last,FORMATS = 'yMdhHmsfztg',date = new Date(0,0,1),h,z,t,//format字符串占位符相对于日期字符串的偏移量//年份、世纪、时区 会出现负数，导致位移//月份全称长度不固定，导致位移p = 0,<span style="white-space:pre"></span>str;frm = frm.split('');//i <= frm.length 多取一位，在循环中完全处理掉日期替换for (var i = 0; i <= frm.length; i++) {if(frm[i]!==last){if (place) {place = place.join('');str = subDateStr(dateStr,place,i,p);p = str.p;set(str.str, place);};place = null;if (FORMATS.indexOf(frm[i]) >= 0) {place = [frm[i]];};}else{place && place.push(frm[i]);}last = frm[i];};if (h) {t == 'PM' && (h += 12);date.setHours(h);};if (z) {z = new Date().getTimezoneOffset() / 60 - z;date.setHours(date.getHours() + z);};return date;function subDateStr(dateStr,place,i,p){if (!place || !place.length) {return '';};var start = 0,str;if (place == 'MMMM') { //月份全称，长度不固定，特殊处理start = p + i - place.length;str = dateStr.substring(start,p + i - 1);for (var j = 0; j < MONTHNAMES.length; j++) {if(MONTHNAMES[j].indexOf(str) >= 0){str = MONTHNAMES[j];break;}};p+=(str.length - place.length);}else{start = p + i - place.length;str = dateStr.substring(start,p + i);if (place.indexOf('y') == 0 || place.indexOf('z') == 0 || place.indexOf('g') == 0) {if (str.indexOf('-') == 0) { //处理负数str = dateStr.substring(start,p + i+1);p++;};}}return {str:str || '',p:p};};function set(str,place){if (!place || !place.length || !str || !str.length) {return;};var v,c;if (/M{3,}/.test(place)) {for (var i = 0; i < MONTHNAMES.length; i++) {if(MONTHNAMES[i].indexOf(str) == 0){v = i;break;}};v != null && date.setMonth(v);}else if (place == 'yy' || place == 'y') {var Y = fix(new Date().getFullYear().toString(),4,'0',true);Y = Y.substr(0,Y.length-2);Y += fix(str,2,'0',true);v = parseInt(Y);date.setFullYear(v);}else{c = place.substr(0,1);if (c == 't') {t = place.length == 1 ? str + 'M' : str;}else{v = parseInt(str);switch(c){case 'h':h = v;break;case 'z':z = v;break;case 'y':date.setFullYear(v);break;case 'M':date.setMonth(v-1);break;case 'd':date.setDate(v);break;case 'H':date.setHours(v);break;case 'm':date.setMinutes(v);break;case 's':date.setSeconds(v);break;case 'f':date.setMilliseconds(v);break;}}}}};