如何在不更改区域性的情况下格式化日期字符串？

Question

I am getting string data from a Google Calendar feed. The date is already set, by parameter, with the desired timezone.

2014-05-24T07:00:00.000-04:00 

I know there are wonderful libraries like moment.js and date.js this will help format my date, but they also work with a Date object, which throws my date into a client's culture. At that point I am then juggling offsets. Would rather avoid that.

Other than a lot of conditional string manipulation, is there a simple way to do this, or I am oversimplifying (again)?

Example:

2014-05-24T07:00:00.000-04:00 to May, 24, 2014 - 7:00 AM

Answer 1

The following short code will parse your date, using the values present, without offsetting by the timezone:

var months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
        'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
var res = /(\d+)\-(\d+)\-(\d+)T(\d+)\:(\d+)/
        .exec('2014-05-24T07:00:00.000-04:00');
var am = (res[4] < 12);
var date = months[res[2]-1] + ', ' + res[3] + ', ' + res[1];
var time = am ? (parseInt(res[4]) + ':' + res[5] + 'AM') :
        (res[4] - 12 + ':' + res[5] + 'PM');
var formatted = date + ' - ' + time;
console.log(formatted);

Answer 2

You can convert this string into a Date object like below,

new Date("2014-05-24T07:00:00.000-04:00")

Then you can easily convert this date object into your desired format by using any of the jQuery libraries such as jquery.globalize.js ...

Answer 3

Here you go:

var d = new Date('2014-05-24T07:00:00.000-04:00');

var calendar = {
    months: {
        full: ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'],
        short: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
    },
    days: {
        full: ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday'],
        short: ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
    }
};

console.log(calendar.months.short[d.getMonth()]+', '+d.getDate()+', '+d.getFullYear());

Answer 4

A simple function to reformat the string is:

function reformatDateString(s) {
  s = s.match(/\d+/g);
  var months = ['January','February','March','April','May','June','July',
                'August','September','October','November','December'];
  var ampm = s[3]<12? 'AM':'PM';
  return months[--s[1]] + ', ' + +s[2] + ', ' + s[0] + ' - ' +
               (s[3]%12 || 12) + ':' + s[4] + ' ' + ampm;
}

console.log(reformatDateString('2014-05-24T07:00:00.000-04:00')); // May, 24, 2014 - 7:00 AM
console.log(reformatDateString('2014-05-24T17:00:00.000-04:00')); // May, 24, 2014 - 5:00 PM
console.log(reformatDateString('2014-05-04T00:20:00.000-04:00')); // May, 4, 2014 - 12:20 AM

Which also assumes that you don't want leading zeros on single digit numbers except for the minutes, as a time like 12:5 PM isn't as readable (to me) as 12:05 PM .

Also you may need to modify the months array, it's not clear in the OP whether you want full month names or abbreviations (Jan, Feb, etc.).