如何将Date对象格式化为字符串?
当前回答
字体版本
可以轻松增强以支持所需的任何格式字符串。当这样的通用解决方案非常容易创建,并且应用程序中经常出现日期格式时,我不建议在应用程序中对日期格式代码进行硬编码。这很难读懂,也隐藏了你的意图。格式字符串清楚地显示您的意图。
原型函数
interface Date {
format(formatString: string): string;
}
Date.prototype.format = function (formatString: string): string {
return Object.entries({
YYYY: this.getFullYear(),
YY: this.getFullYear().toString().substring(2),
yyyy: this.getFullYear(),
yy: this.getFullYear().toString().substring(2),
MMMM: this.toLocaleString('default', { month: 'long' }),
MMM: this.toLocaleString('default', { month: 'short' }),
MM: (this.getMonth() + 1).toString().padStart(2, '0'),
M: this.getMonth() + 1,
DDDD: this.toLocaleDateString('default', { weekday: 'long' }),
DDD: this.toLocaleDateString('default', { weekday: 'short' }),
DD: this.getDate().toString().padStart(2, '0'),
D: this.getDate(),
dddd: this.toLocaleDateString('default', { weekday: 'long' }),
ddd: this.toLocaleDateString('default', { weekday: 'short' }),
dd: this.getDate().toString().padStart(2, '0'),
d: this.getDate(),
HH: this.getHours().toString().padStart(2, '0'), // military
H: this.getHours().toString(), // military
hh: (this.getHours() % 12).toString().padStart(2, '0'),
h: (this.getHours() % 12).toString(),
mm: this.getMinutes().toString().padStart(2, '0'),
m: this.getMinutes(),
SS: this.getSeconds().toString().padStart(2, '0'),
S: this.getSeconds(),
ss: this.getSeconds().toString().padStart(2, '0'),
s: this.getSeconds(),
TTT: this.getMilliseconds().toString().padStart(3, '0'),
ttt: this.getMilliseconds().toString().padStart(3, '0'),
AMPM: this.getHours() < 13 ? 'AM' : 'PM',
ampm: this.getHours() < 13 ? 'am' : 'pm',
}).reduce((acc, entry) => {
return acc.replace(entry[0], entry[1].toString())
}, formatString)
}
Javascript版本
同样,只需删除接口,以及冒号及其关联冒号之后的类型名称。
demo
function unitTest() {
var d: Date = new Date()
console.log(d.format('MM/dd/yyyy hh:mm:ss')) // 12/14/2022 03:38:31
console.log(d.format('yyyy-MM-dd HH:mm:ss')) // 2022-12-14 15:38:31
}
unitTest()
其他回答
设置日期格式的其他方式:
function formatDate(dDate,sMode){
var today = dDate;
var dd = today.getDate();
var mm = today.getMonth()+1; //January is 0!
var yyyy = today.getFullYear();
if(dd<10) {
dd = '0'+dd
}
if(mm<10) {
mm = '0'+mm
}
if (sMode+""==""){
sMode = "dd/mm/yyyy";
}
if (sMode == "yyyy-mm-dd"){
return yyyy + "-" + mm + "-" + dd + "";
}
if (sMode == "dd/mm/yyyy"){
return dd + "/" + mm + "/" + yyyy;
}
}
以下代码将允许您将日期格式设置为DD-MM-YYYY(2017年12月27日)或DD-MM-YYYY(2017年10月26日):
/** Pad number to fit into nearest power of 10 */
function padNumber(number, prependChar, count) {
var out = '' + number; var i;
if (number < Math.pow(10, count))
while (out.length < ('' + Math.pow(10, count)).length) out = prependChar + out;
return out;
}
/* Format the date to 'DD-MM-YYYY' or 'DD MMM YYYY' */
function dateToDMY(date, useNumbersOnly) {
var months = [
'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct',
'Nov', 'Dec'
];
return '' + padNumber(date.getDate(), '0', 1) +
(useNumbersOnly? '-' + padNumber(date.getMonth() + 1, '0', 1) + '-' : ' ' + months[date.getMonth()] + ' ')
+ date.getFullYear();
}
更改date.getFullYear()和padNumber(date.getDate(),“0”,1)的顺序,以生成dateToYMD()函数。
有关详细信息,请参见repl.it示例。
这是我刚刚编写的一些代码,用于处理我正在处理的项目的日期格式。它模仿了PHP日期格式功能,以满足我的需要。请随意使用它,它只是扩展了现有的Date()对象。这可能不是最优雅的解决方案,但它符合我的需求。
var d = new Date();
d_string = d.format("m/d/Y h:i:s");
/**************************************
* Date class extension
*
*/
// Provide month names
Date.prototype.getMonthName = function(){
var month_names = [
'January',
'February',
'March',
'April',
'May',
'June',
'July',
'August',
'September',
'October',
'November',
'December'
];
return month_names[this.getMonth()];
}
// Provide month abbreviation
Date.prototype.getMonthAbbr = function(){
var month_abbrs = [
'Jan',
'Feb',
'Mar',
'Apr',
'May',
'Jun',
'Jul',
'Aug',
'Sep',
'Oct',
'Nov',
'Dec'
];
return month_abbrs[this.getMonth()];
}
// Provide full day of week name
Date.prototype.getDayFull = function(){
var days_full = [
'Sunday',
'Monday',
'Tuesday',
'Wednesday',
'Thursday',
'Friday',
'Saturday'
];
return days_full[this.getDay()];
};
// Provide full day of week name
Date.prototype.getDayAbbr = function(){
var days_abbr = [
'Sun',
'Mon',
'Tue',
'Wed',
'Thur',
'Fri',
'Sat'
];
return days_abbr[this.getDay()];
};
// Provide the day of year 1-365
Date.prototype.getDayOfYear = function() {
var onejan = new Date(this.getFullYear(),0,1);
return Math.ceil((this - onejan) / 86400000);
};
// Provide the day suffix (st,nd,rd,th)
Date.prototype.getDaySuffix = function() {
var d = this.getDate();
var sfx = ["th","st","nd","rd"];
var val = d%100;
return (sfx[(val-20)%10] || sfx[val] || sfx[0]);
};
// Provide Week of Year
Date.prototype.getWeekOfYear = function() {
var onejan = new Date(this.getFullYear(),0,1);
return Math.ceil((((this - onejan) / 86400000) + onejan.getDay()+1)/7);
}
// Provide if it is a leap year or not
Date.prototype.isLeapYear = function(){
var yr = this.getFullYear();
if ((parseInt(yr)%4) == 0){
if (parseInt(yr)%100 == 0){
if (parseInt(yr)%400 != 0){
return false;
}
if (parseInt(yr)%400 == 0){
return true;
}
}
if (parseInt(yr)%100 != 0){
return true;
}
}
if ((parseInt(yr)%4) != 0){
return false;
}
};
// Provide Number of Days in a given month
Date.prototype.getMonthDayCount = function() {
var month_day_counts = [
31,
this.isLeapYear() ? 29 : 28,
31,
30,
31,
30,
31,
31,
30,
31,
30,
31
];
return month_day_counts[this.getMonth()];
}
// format provided date into this.format format
Date.prototype.format = function(dateFormat){
// break apart format string into array of characters
dateFormat = dateFormat.split("");
var date = this.getDate(),
month = this.getMonth(),
hours = this.getHours(),
minutes = this.getMinutes(),
seconds = this.getSeconds();
// get all date properties ( based on PHP date object functionality )
var date_props = {
d: date < 10 ? '0'+date : date,
D: this.getDayAbbr(),
j: this.getDate(),
l: this.getDayFull(),
S: this.getDaySuffix(),
w: this.getDay(),
z: this.getDayOfYear(),
W: this.getWeekOfYear(),
F: this.getMonthName(),
m: month < 10 ? '0'+(month+1) : month+1,
M: this.getMonthAbbr(),
n: month+1,
t: this.getMonthDayCount(),
L: this.isLeapYear() ? '1' : '0',
Y: this.getFullYear(),
y: this.getFullYear()+''.substring(2,4),
a: hours > 12 ? 'pm' : 'am',
A: hours > 12 ? 'PM' : 'AM',
g: hours % 12 > 0 ? hours % 12 : 12,
G: hours > 0 ? hours : "12",
h: hours % 12 > 0 ? hours % 12 : 12,
H: hours,
i: minutes < 10 ? '0' + minutes : minutes,
s: seconds < 10 ? '0' + seconds : seconds
};
// loop through format array of characters and add matching data else add the format character (:,/, etc.)
var date_string = "";
for(var i=0;i<dateFormat.length;i++){
var f = dateFormat[i];
if(f.match(/[a-zA-Z]/g)){
date_string += date_props[f] ? date_props[f] : '';
} else {
date_string += f;
}
}
return date_string;
};
/*
*
* END - Date class extension
*
************************************/
注意(2022-10):toLocaleFormat已被弃用一段时间,并从Firefox版本58中删除。请参见LocaleFormat
我想你可以使用非标准的Date方法来LocaleFormat(formatString)
formatString:与C中strftime()函数期望的格式相同的格式字符串。
var today = new Date();
today.toLocaleFormat('%d-%b-%Y'); // 30-Dec-2011
参考文献:
到区域设置格式斯特夫蒂姆
好的,我们有一个叫做Intl的东西,这对在JavaScript中格式化日期非常有用:
您的日期如下:
var date = '10/8/2010';
然后使用如下所示的新Date()更改为Date:
date = new Date(date);
现在,您可以使用以下区域设置列表以任何方式对其进行格式化:
date = new Intl.DateTimeFormat('en-AU').format(date); // Australian date format: "8/10/2010"
date = new Intl.DateTimeFormat('en-US').format(date); // USA date format: "10/8/2010"
date = new Intl.DateTimeFormat('ar-EG').format(date); // Arabic date format: "٨/١٠/٢٠١٠"
如果您确实想要上面提到的格式,可以执行以下操作:
date = new Date(Date.UTC(2010, 7, 10, 0, 0, 0));
var options = {year: "numeric", month: "short", day: "numeric"};
date = new Intl.DateTimeFormat("en-AU", options).format(date).replace(/\s/g, '-');
结果将是:
"10-Aug-2010"
有关详细信息,请参阅Intl API和Intl.DateTimeFormat文档。