使用javascript格式化DATE（可能正则表达式）

Question

I'm using JavaScript and JQuery and I've got a string like this (unchangeable xml response):

var str = "2017-01-08T16:06:52+00:00";

How can I convert to a Date like this:

08 january 2017, 16:06:52

Or at least:

08 01 2017, 16:06:52

I was trying to use a .replace() like:

str = str.replace(/(\d{4})-(\d{2})-(\d{2})T(\d{8}).*/,'$2 $3 $1, $4');

But it doesn't works. :(

Answer 1

To do this you can create a Date() object from the string, then concatenate together a string from the methods the Date() object exposes. Try this:

 var str = "2017-01-08T16:06:52+00:00"; var date = new Date(str); var months = [ "january", "february", "march", "april", "may", "june", "july", "august", "september", "october", "november", "december" ]; var dateString = ("00" + date.getDate()).slice(-2) + ' ' + months[date.getMonth()] + ' ' + date.getFullYear() + ', ' + ("00" + date.getHours()).slice(-2) + ':' + ("00" + date.getMinutes()).slice(-2) + ':' + ("00" + date.getSeconds()).slice(-2); console.log(dateString); 

Note that this can be made simpler by using a date formatting library (such as MomentJS or DateJS) however including an entire library to format a single date is rather wasteful. If you need to do this repeatedly throughout your site then they may be worth it.

Also note that in English speaking countries the month names should be capitalised, so consider amending the format for that case.

Answer 2

Alternatively, if adding a library is an option you could use moment.js . You can call .format and pass how you would like the output to be, for example:

 var str = "2017-01-08T16:06:52+00:00"; var momentDate = moment(str); console.log(momentDate.format('DD MMMM YYYY HH:mm:ss')); 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.17.1/moment.js"></script> 

Answer 3

Your regular expression isn't quite right, \\d{8} will match 8 consecutive digits but there are colons in there as well, you need something like:

 var str = "2017-01-08T16:06:52+00:00" str = str.replace(/(\\d{4})-(\\d{2})-(\\d{2})T(.{8}).*/, '$2 $3 $1, $4'); console.log(str) 

To replace the month number with the name is just a little more work:

 function reformatDate(s) { var months = [ "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December" ]; var b = s.split(/\\D/); return b[2] + ' ' + months[b[1]-1] + ', ' + b[0] + ' ' + b[3] + ':' + b[4] + ':' + b[5]; } var s = "2017-01-08T16:06:52+00:00" console.log(reformatDate(s)); 

Be careful using the Date constructor (and Date.parse) for parsing strings, it's largely implementation dependent.

If you want to present the date and time in the timezone of the client, then parse the string to a Date, then return it as a string. A library like fecha.js is good for that. It's small and just does parsing and formatting, eg

var s = '2017-01-08T16:06:52+00:00'
var d = fecha.parse(s,'YYYY-MM-DDTHH:mm:ssZZ');

console.log(fecha.format(d,'dd MMMM, YYYY HH:mm:ss'));