将字符串转换为格式化日期

Question

I have written JavaScript code that reads text fields named leave_start and leave_end and determines the dates that fall between them. Currently, the dates I am creating look like this:

Mon Apr 6 2015 00:00:00 GMT-0400

However, I want each date to instead look like this:

Mon Apr 6 2015

As you can see, I simply want to strip off the time component. Can anyone help?

---

Framework: Ruby on rails 4.1.8

This is my app.js that looks at my two datepicker text fields ( leave_start and leave_end ).

$(document).ready(function () {

    $('.customSub').click(function () {

        var start = $('#leave_start').datepicker("getDate"),
            end = $('#leave_end').datepicker("getDate"),
            currentDate = new Date(start),
            between = [];

        while (currentDate <= end) {
            between.push(new Date(currentDate));
            currentDate.setDate(currentDate.getDate() + 1);
        }

        var formated_dates = between.reduce(function (dates, date) {
            dates.push(date.toString());
            return dates;
        }, []);
        $('#gdates').val(formated_dates.join("\n"));

    });
});

Based off the answer by @Nikos M., would this be the correct way of doing it?

$(document).ready(function() {

    $('.customSub').click(function() {

        var start = $('#leave_start').datepicker("getDate"),
            end = $('#leave_end').datepicker("getDate"),
            currentDate = new Date(start),
            between = []
        ;

        while (currentDate <= end) {
            between.push(new Date(currentDate));
            currentDate.setDate(currentDate.getDate() + 1);
        }
        var date_start = new Date();
        console.log(date('Y-m-d', date_start));

        var formated_dates = between.reduce(function(dates, date){
            dates.push(date.toString());
            return dates;
        }, []);
        $('#gdates').val(formated_dates.join("\n"));

    });
  });

---

Additional information

This is my index view where I would like full_range to look like Mon Apr 6 2015 instead of Mon Apr 6 2015 00:00:00 GMT-0400 . I tried using .strftime('%m/%d/%y') on full_range but it didn't work. full_range is #gdates in my JavaScript.

 %table.table.table-bordered.trace-table
   %tr
   -@entry.each do |e|
     %tr
       %td.trace-table.bordered.trace-table{:style => 'width:8%;'}= e.leave_start.strftime('%m/%d/%y')
       %td.trace-table.bordered.trace-table{:style => 'width:8%;'}= e.leave_end.strftime('%m/%d/%y')
       %td.trace-table.bordered.trace-table{:style => 'width:8%;'}= e.full_range

Finally, this is my entry table:

create_table "entries"
  t.datetime "created_at"
  t.datetime "updated_at"
  t.datetime "leave_start"
  t.datetime "leave_end"
    t.string "full_range"

Answer 1

to_date() public Converts a string to a Date value.

> "1-1-2012".to_date   # => Sun, 01 Jan 2012
> "01/01/2012".to_date # => Sun, 01 Jan 2012
> "2012-12-13".to_date # => Thu, 13 Dec 2012

Source : http://apidock.com/rails/String/to_date

Answer 2

There are varioius libraries around for manipulating dates in various formats like moment.js etc

What you need here is a function to convert the date into a given format. Javascript already has a limited such feature by using date.toString or date.toDate

PHP has a function to format date which has been ported to javascript on php.js project (on github) you can literaly use that function in your project (simply copy-paste it as it is standalone)

PHP date format

You can literaly format the date as you need including time, year etc.. (it is not limited as the js native date methods)

reproducing code here (taken from php.js):

function date(format, timestamp) {
  //  discuss at: http://phpjs.org/functions/date/
  // original by: Carlos R. L. Rodrigues (http://www.jsfromhell.com)
  // original by: gettimeofday
  //    parts by: Peter-Paul Koch (http://www.quirksmode.org/js/beat.html)
  // improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // improved by: MeEtc (http://yass.meetcweb.com)
  // improved by: Brad Touesnard
  // improved by: Tim Wiel
  // improved by: Bryan Elliott
  // improved by: David Randall
  // improved by: Theriault
  // improved by: Theriault
  // improved by: Brett Zamir (http://brett-zamir.me)
  // improved by: Theriault
  // improved by: Thomas Beaucourt (http://www.webapp.fr)
  // improved by: JT
  // improved by: Theriault
  // improved by: Rafał Kukawski (http://blog.kukawski.pl)
  // improved by: Theriault
  //    input by: Brett Zamir (http://brett-zamir.me)
  //    input by: majak
  //    input by: Alex
  //    input by: Martin
  //    input by: Alex Wilson
  //    input by: Haravikk
  // bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // bugfixed by: majak
  // bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // bugfixed by: Brett Zamir (http://brett-zamir.me)
  // bugfixed by: omid (http://phpjs.org/functions/380:380#comment_137122)
  // bugfixed by: Chris (http://www.devotis.nl/)
  //        note: Uses global: php_js to store the default timezone
  //        note: Although the function potentially allows timezone info (see notes), it currently does not set
  //        note: per a timezone specified by date_default_timezone_set(). Implementers might use
  //        note: this.php_js.currentTimezoneOffset and this.php_js.currentTimezoneDST set by that function
  //        note: in order to adjust the dates in this function (or our other date functions!) accordingly
  //   example 1: date('H:m:s \\m \\i\\s \\m\\o\\n\\t\\h', 1062402400);
  //   returns 1: '09:09:40 m is month'
  //   example 2: date('F j, Y, g:i a', 1062462400);
  //   returns 2: 'September 2, 2003, 2:26 am'
  //   example 3: date('Y W o', 1062462400);
  //   returns 3: '2003 36 2003'
  //   example 4: x = date('Y m d', (new Date()).getTime()/1000);
  //   example 4: (x+'').length == 10 // 2009 01 09
  //   returns 4: true
  //   example 5: date('W', 1104534000);
  //   returns 5: '53'
  //   example 6: date('B t', 1104534000);
  //   returns 6: '999 31'
  //   example 7: date('W U', 1293750000.82); // 2010-12-31
  //   returns 7: '52 1293750000'
  //   example 8: date('W', 1293836400); // 2011-01-01
  //   returns 8: '52'
  //   example 9: date('W Y-m-d', 1293974054); // 2011-01-02
  //   returns 9: '52 2011-01-02'

  var that = this;
  var jsdate, f;
  // Keep this here (works, but for code commented-out below for file size reasons)
  // var tal= [];
  var txt_words = [
    'Sun', 'Mon', 'Tues', 'Wednes', 'Thurs', 'Fri', 'Satur',
    'January', 'February', 'March', 'April', 'May', 'June',
    'July', 'August', 'September', 'October', 'November', 'December'
  ];
  // trailing backslash -> (dropped)
  // a backslash followed by any character (including backslash) -> the character
  // empty string -> empty string
  var formatChr = /\\?(.?)/gi;
  var formatChrCb = function (t, s) {
    return f[t] ? f[t]() : s;
  };
  var _pad = function (n, c) {
    n = String(n);
    while (n.length < c) {
      n = '0' + n;
    }
    return n;
  };
  f = {
    // Day
    d: function () {
      // Day of month w/leading 0; 01..31
      return _pad(f.j(), 2);
    },
    D: function () {
      // Shorthand day name; Mon...Sun
      return f.l()
        .slice(0, 3);
    },
    j: function () {
      // Day of month; 1..31
      return jsdate.getDate();
    },
    l: function () {
      // Full day name; Monday...Sunday
      return txt_words[f.w()] + 'day';
    },
    N: function () {
      // ISO-8601 day of week; 1[Mon]..7[Sun]
      return f.w() || 7;
    },
    S: function () {
      // Ordinal suffix for day of month; st, nd, rd, th
      var j = f.j();
      var i = j % 10;
      if (i <= 3 && parseInt((j % 100) / 10, 10) == 1) {
        i = 0;
      }
      return ['st', 'nd', 'rd'][i - 1] || 'th';
    },
    w: function () {
      // Day of week; 0[Sun]..6[Sat]
      return jsdate.getDay();
    },
    z: function () {
      // Day of year; 0..365
      var a = new Date(f.Y(), f.n() - 1, f.j());
      var b = new Date(f.Y(), 0, 1);
      return Math.round((a - b) / 864e5);
    },

    // Week
    W: function () {
      // ISO-8601 week number
      var a = new Date(f.Y(), f.n() - 1, f.j() - f.N() + 3);
      var b = new Date(a.getFullYear(), 0, 4);
      return _pad(1 + Math.round((a - b) / 864e5 / 7), 2);
    },

    // Month
    F: function () {
      // Full month name; January...December
      return txt_words[6 + f.n()];
    },
    m: function () {
      // Month w/leading 0; 01...12
      return _pad(f.n(), 2);
    },
    M: function () {
      // Shorthand month name; Jan...Dec
      return f.F()
        .slice(0, 3);
    },
    n: function () {
      // Month; 1...12
      return jsdate.getMonth() + 1;
    },
    t: function () {
      // Days in month; 28...31
      return (new Date(f.Y(), f.n(), 0))
        .getDate();
    },

    // Year
    L: function () {
      // Is leap year?; 0 or 1
      var j = f.Y();
      return j % 4 === 0 & j % 100 !== 0 | j % 400 === 0;
    },
    o: function () {
      // ISO-8601 year
      var n = f.n();
      var W = f.W();
      var Y = f.Y();
      return Y + (n === 12 && W < 9 ? 1 : n === 1 && W > 9 ? -1 : 0);
    },
    Y: function () {
      // Full year; e.g. 1980...2010
      return jsdate.getFullYear();
    },
    y: function () {
      // Last two digits of year; 00...99
      return f.Y()
        .toString()
        .slice(-2);
    },

    // Time
    a: function () {
      // am or pm
      return jsdate.getHours() > 11 ? 'pm' : 'am';
    },
    A: function () {
      // AM or PM
      return f.a()
        .toUpperCase();
    },
    B: function () {
      // Swatch Internet time; 000..999
      var H = jsdate.getUTCHours() * 36e2;
      // Hours
      var i = jsdate.getUTCMinutes() * 60;
      // Minutes
      // Seconds
      var s = jsdate.getUTCSeconds();
      return _pad(Math.floor((H + i + s + 36e2) / 86.4) % 1e3, 3);
    },
    g: function () {
      // 12-Hours; 1..12
      return f.G() % 12 || 12;
    },
    G: function () {
      // 24-Hours; 0..23
      return jsdate.getHours();
    },
    h: function () {
      // 12-Hours w/leading 0; 01..12
      return _pad(f.g(), 2);
    },
    H: function () {
      // 24-Hours w/leading 0; 00..23
      return _pad(f.G(), 2);
    },
    i: function () {
      // Minutes w/leading 0; 00..59
      return _pad(jsdate.getMinutes(), 2);
    },
    s: function () {
      // Seconds w/leading 0; 00..59
      return _pad(jsdate.getSeconds(), 2);
    },
    u: function () {
      // Microseconds; 000000-999000
      return _pad(jsdate.getMilliseconds() * 1000, 6);
    },

    // Timezone
    e: function () {
      // Timezone identifier; e.g. Atlantic/Azores, ...
      // The following works, but requires inclusion of the very large
      // timezone_abbreviations_list() function.
      /*              return that.date_default_timezone_get();
       */
      throw 'Not supported (see source code of date() for timezone on how to add support)';
    },
    I: function () {
      // DST observed?; 0 or 1
      // Compares Jan 1 minus Jan 1 UTC to Jul 1 minus Jul 1 UTC.
      // If they are not equal, then DST is observed.
      var a = new Date(f.Y(), 0);
      // Jan 1
      var c = Date.UTC(f.Y(), 0);
      // Jan 1 UTC
      var b = new Date(f.Y(), 6);
      // Jul 1
      // Jul 1 UTC
      var d = Date.UTC(f.Y(), 6);
      return ((a - c) !== (b - d)) ? 1 : 0;
    },
    O: function () {
      // Difference to GMT in hour format; e.g. +0200
      var tzo = jsdate.getTimezoneOffset();
      var a = Math.abs(tzo);
      return (tzo > 0 ? '-' : '+') + _pad(Math.floor(a / 60) * 100 + a % 60, 4);
    },
    P: function () {
      // Difference to GMT w/colon; e.g. +02:00
      var O = f.O();
      return (O.substr(0, 3) + ':' + O.substr(3, 2));
    },
    T: function () {
      // Timezone abbreviation; e.g. EST, MDT, ...
      // The following works, but requires inclusion of the very
      // large timezone_abbreviations_list() function.
      /*              var abbr, i, os, _default;
      if (!tal.length) {
        tal = that.timezone_abbreviations_list();
      }
      if (that.php_js && that.php_js.default_timezone) {
        _default = that.php_js.default_timezone;
        for (abbr in tal) {
          for (i = 0; i < tal[abbr].length; i++) {
            if (tal[abbr][i].timezone_id === _default) {
              return abbr.toUpperCase();
            }
          }
        }
      }
      for (abbr in tal) {
        for (i = 0; i < tal[abbr].length; i++) {
          os = -jsdate.getTimezoneOffset() * 60;
          if (tal[abbr][i].offset === os) {
            return abbr.toUpperCase();
          }
        }
      }
      */
      return 'UTC';
    },
    Z: function () {
      // Timezone offset in seconds (-43200...50400)
      return -jsdate.getTimezoneOffset() * 60;
    },

    // Full Date/Time
    c: function () {
      // ISO-8601 date.
      return 'Y-m-d\\TH:i:sP'.replace(formatChr, formatChrCb);
    },
    r: function () {
      // RFC 2822
      return 'D, d M Y H:i:s O'.replace(formatChr, formatChrCb);
    },
    U: function () {
      // Seconds since UNIX epoch
      return jsdate / 1000 | 0;
    }
  };
  this.date = function (format, timestamp) {
    that = this;
    jsdate = (timestamp === undefined ? new Date() : // Not provided
      (timestamp instanceof Date) ? new Date(timestamp) : // JS Date()
      new Date(timestamp * 1000) // UNIX timestamp (auto-convert to int)
    );
    return format.replace(formatChr, formatChrCb);
  };
  return this.date(format, timestamp);
}

use as such:

var date_start = new Date();
/* use any format you like here */
console.log(date('Y-m-d', Math.floor(date_start.getTime() / 1000)));
// or even this
console.log(date('Y-m-d', date_start));

output:

2015-05-08

Answer 3

d = new Date will return << Wed Apr 08 2015 18:45:45 GMT+0530 (IST)

d.toDateString will return << "Wed Apr 08 2015"

Answer 4

try this in rails c

d = DateTime.now

d.to_date