js中日期的加减法

2024-05-06 16:19:26

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JavaScript实现日期加减计算功能代码实例，因为在js中没有类似C#中的AddDays方法，所以要想实现日期加减的话，就需要自己写函数来实现。

今天就算对JS中日期的加减法做个总结，一共两步

第一步，引入date.format.js，这个JS的作用是将日期转为指定的格式，代码如下

var dateFormat = function () {

var token = /d{1,4}|m{1,4}|yy(?:yy)?|([HhMsTt])/1?|[LloSZ]|"[^"]*"|'[^']*'/g,

timezone = //b(?:[PMCEA][SDP]T|(?:Pacific|Mountain|Central|Eastern|Atlantic) (?:Standard|Daylight|Prevailing) Time|(?:GMT|UTC)(?:[-+]/d{4})?)/b/g,

timezoneClip = /[^-+/dA-Z]/g,

pad = function (val, len) {

val = String(val);

len = len || 2;

while (val.length < len) val = "0" + val;

return val;

};

// Regexes and supporting functions are cached through closure

return function (date, mask, utc) {

var dF = dateFormat;

// You can't provide utc if you skip other args (use the "UTC:" mask prefix)

if (arguments.length == 1 && Object.prototype.toString.call(date) == "[object String]" && !//d/.test(date)) {

mask = date;

date = undefined;

}

// Passing date through Date applies Date.parse, if necessary

date = date ? new Date(date) : new Date;

if (isNaN(date)) throw SyntaxError("invalid date");

mask = String(dF.masks[mask] || mask || dF.masks["default"]);

// Allow setting the utc argument via the mask

if (mask.slice(0, 4) == "UTC:") {

mask = mask.slice(4);

utc = true;

}

var _ = utc ? "getUTC" : "get",

d = date[_ + "Date"](),

D = date[_ + "Day"](),

m = date[_ + "Month"](),

y = date[_ + "FullYear"](),

H = date[_ + "Hours"](),

M = date[_ + "Minutes"](),

s = date[_ + "Seconds"](),

L = date[_ + "Milliseconds"](),

o = utc ? 0 : date.getTimezoneOffset(),

flags = {

d: d,

dd: pad(d),

ddd: dF.i18n.dayNames[D],

dddd: dF.i18n.dayNames[D + 7],

m: m + 1,

mm: pad(m + 1),

mmm: dF.i18n.monthNames[m],

mmmm: dF.i18n.monthNames[m + 12],

yy: String(y).slice(2),

yyyy: y,

h: H % 12 || 12,

hh: pad(H % 12 || 12),

H: H,

HH: pad(H),

M: M,

MM: pad(M),

s: s,

ss: pad(s),

l: pad(L, 3),

L: pad(L > 99 ? Math.round(L / 10) : L),

t: H < 12 ? "a" : "p",

tt: H < 12 ? "am" : "pm",

T: H < 12 ? "A" : "P",

TT: H < 12 ? "AM" : "PM",

Z: utc ? "UTC" : (String(date).match(timezone) || [""]).pop().replace(timezoneClip, ""),

o: (o > 0 ? "-" : "+") + pad(Math.floor(Math.abs(o) / 60) * 100 + Math.abs(o) % 60, 4),

S: ["th", "st", "nd", "rd"][d % 10 > 3 ? 0 : (d % 100 - d % 10 != 10) * d % 10]

};

return mask.replace(token, function ($0) {

return $0 in flags ? flags[$0] : $0.slice(1, $0.length - 1);

});

};

}();

// Some common format strings

dateFormat.masks = {

"default": "ddd mmm dd yyyy HH:MM:ss",

shortDate: "m/d/yy",

mediumDate: "mmm d, yyyy",

longDate: "mmmm d, yyyy",

fullDate: "dddd, mmmm d, yyyy",

shortTime: "h:MM TT",

mediumTime: "h:MM:ss TT",

longTime: "h:MM:ss TT Z",

isoDate: "yyyy-mm-dd",

isoTime: "HH:MM:ss",

isoDateTime: "yyyy-mm-dd'T'HH:MM:ss",

isoUtcDateTime: "UTC:yyyy-mm-dd'T'HH:MM:ss'Z'"

};

// Internationalization strings

dateFormat.i18n = {

dayNames: [

"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat",

"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"

],

monthNames: [

"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec",

"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"

]

};

// For convenience...

Date.prototype.format = function (mask, utc) {

return dateFormat(this, mask, utc);

};

第二步，将时间转换为毫秒进行加减计算，然后再用上面的js的转为指定的日期

var nowDate = new Date();

//加法操作

var ysDate = new Date(nowDate.getTime()-30*24*60*60*1000).format('yyyy-mm-dd');

//减法操作

var yeDate = new Date(nowDate.getTime()-24*60*60*1000).format('yyyy-m-d');