如何格式化 JavaScript 日期

在 JavaScript 中,如何将日期对象格式化为 10-Aug-2010

If you need slightly less control over formatting than the currently accepted answer, Date#toLocaleDateString can be used to create standard locale-specific renderings. The locale and options arguments let applications specify the language whose formatting conventions should be used, and allow some customization of the rendering.

Options key examples:

  1. day:
    The representation of the day.
    Possible values are "numeric", "2-digit".
  2. weekday:
    The representation of the weekday.
    Possible values are "narrow", "short", "long".
  3. year:
    The representation of the year.
    Possible values are "numeric", "2-digit".
  4. month:
    The representation of the month.
    Possible values are "numeric", "2-digit", "narrow", "short", "long".
  5. hour:
    The representation of the hour.
    Possible values are "numeric", "2-digit".
  6. minute: The representation of the minute.
    Possible values are "numeric", "2-digit".
  7. second:
    The representation of the second.
    Possible values are "numeric", 2-digit".

All these keys are optional. You can change the number of options values based on your requirements, and this will also reflect the presence of each date time term.

Note: If you would only like to configure the content options, but still use the current locale, passing null for the first parameter will cause an error. Use undefined instead.

For different languages:

  1. "en-US": For English
  2. "hi-IN": For Hindi
  3. "ja-JP": For Japanese

You can use more language options.

For example

var options = { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' };
var today  = new Date();

console.log(today.toLocaleDateString(“en-US”)); // 9/17/2016
console.log(today.toLocaleDateString(“en-US”, options)); // Saturday, September 17, 2016
console.log(today.toLocaleDateString(“hi-IN”, options)); // शनिवार, 17 सितंबर 2016

You can also use the toLocaleString() method for the same purpose. The only difference is this function provides the time when you don't pass any options.

// Example
9/17/2016, 1:21:34 PM

References:

For custom-delimited date formats, you have to pull out the date (or time) components from a DateTimeFormat object (which is part of the ECMAScript Internationalization API), and then manually create a string with the delimiters you want.

To do this, you can use DateTimeFormat#formatToParts. You could destructure the array, but that is not ideal, as the array output depends on the locale:

{ // example 1
   let f = new Intl.DateTimeFormat('en');
   let a = f.formatToParts();
   console.log(a);
}
{ // example 2
   let f = new Intl.DateTimeFormat('hi');
   let a = f.formatToParts();
   console.log(a);
}

Better would be to map a format array to resultant strings:

function join(t, a, s) {
   function format(m) {
      let f = new Intl.DateTimeFormat('en', m);
      return f.format(t);
   }
   return a.map(format).join(s);
}

let a = [{day: ‘numeric’}, {month: ‘short’}, {year: ‘numeric’}];
let s = join(new Date, a, ‘-’);
console.log(s);

You can also pull out the parts of a DateTimeFormat one-by-one using DateTimeFormat#format, but note that when using this method, as of March 2020, there is a bug in the ECMAScript implementation when it comes to leading zeros on minutes and seconds (this bug is circumvented by the approach above).

let d = new Date(2010, 7, 5);
let ye = new Intl.DateTimeFormat('en', { year: 'numeric' }).format(d);
let mo = new Intl.DateTimeFormat('en', { month: 'short' }).format(d);
let da = new Intl.DateTimeFormat('en', { day: '2-digit' }).format(d);
console.log(`${da}-${mo}-${ye}`);

When working with dates and times, it is usually worth using a library (eg. moment.js, luxon) because of the many hidden complexities of the field.

Note that the ECMAScript Internationalization API, used in the solutions above is not supported in IE10 (0.03% global browser market share in Feb 2020).

Requested format in one line - no libraries and no Date methods, just regex:

var d = (new Date()).toString().replace(/\S+\s(\S+)\s(\d+)\s(\d+)\s.*/,'$2-$1-$3');
// date will be formatted as "14-Oct-2015" (pass any date object in place of 'new Date()')

In my testing, this works reliably in the major browsers (Chrome, Safari, Firefox and IE.) As @RobG pointed out, the output of Date.prototype.toString() is implementation-dependent, so for international or non-browser implementations, just test the output to be sure it works right in your JavaScript engine. You can even add some code to test the string output and make sure it's matching what you expect before you do the regex replace.

@Sébastien -- alternative all browser support

new Date(parseInt(496407600)*1000).toLocaleDateString('de-DE', {
year: 'numeric',
month: '2-digit',
day: '2-digit'
}).replace(/\./g, '/');

Documentation: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toLocaleDateString


High-order tagged template literal example based on Date.toLocaleDateString:

const date = new Date(Date.UTC(2020, 4, 2, 3, 23, 16, 738));
const fmt = (dt, lc = "en-US") => (str, ...expr) =>
    str.map((str, i) => str + (expr[i]?dt.toLocaleDateString(lc, expr[i]) :'')).join('')

console.log(fmt(date)${{year: 'numeric'}}-${{month: '2-digit'}}-${{day: '2-digit'}});
// expected output: “2020-05-02”


OK, we have got something called Intl which is very useful for formatting a date in JavaScript these days:

Your date as below:

var date = '10/8/2010';

And you change to Date by using new Date() like below:

date = new Date(date);

And now you can format it any way you like using a list of locales like below:

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"

If you exactly want the format you mentioned above, you can do:

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, '-');

And the result is going to be:

"10-Aug-2010"

For more see the Intl API and Intl.DateTimeFormat documentation.

The Date constructor (and Date.parse()) only accepts one format as a parameter when constructing a date and that is ISO 8601:

// new Date('YYYY-MM-DDTHH:mm:ss.sssZ')
const date = new Date('2017-08-15')

But parsing a from a string is strongly discouraged (MDN recommends against creating date with date strings) due to browser differences and inconsistencies.

The recommended alternative would be building your Date instance directly from the numeric data like this:

new Date(2017, 7, 15) // Month is zero-indexed

That is parsing. Now, to format your date to the string you desire you have several options that are native of the Date object (although I believe none is compliant to the format you require):

date.toString()       // 'Wed Jan 23 2019 17:23:42 GMT+0800 (Singapore Standard Time)'
date.toDateString()   // 'Wed Jan 23 2019'
date.toLocaleString() // '23/01/2019, 17:23:42'
date.toGMTString()    // 'Wed, 23 Jan 2019 09:23:42 GMT'
date.toUTCString()    // 'Wed, 23 Jan 2019 09:23:42 GMT'
date.toISOString()    // '2019-01-23T09:23:42.079Z'

For other formatting options I'm afraid you'll have to turn to libraries such as Moment.js, day.js and the like.

Credit to Zell Liew from this article for the date formatting tips.

A JavaScript solution without using any external libraries:

var now = new Date()
months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
var formattedDate = now.getDate() + "-" + months[now.getMonth()] + "-" + now.getFullYear()
alert(formattedDate)
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