Develop Reference

Have Javascript recognize YYYYmmdd in +5:00 Time Zone [duplicate]

I need my date to be in ccyymmdd format to add a day and pass over to a cobol application via xml. I also need to convert the new date with the added day to mm/dd/ccyy format to place into my slickgrid. My boss believes there has to be an easier way however, I can't seem to find one without using jquery or adding another library. Here is the code I am using;
// Roll date for status R1(rolled) today plus 1 day.
var rDate = (new Date()).toISOString().slice(0, 10).replace(/-/g, "");
(rDate++);
// Convert rDate back to useable date for updating ActionDate when rolling clt.
var uDate = (String(rDate)).replace(/(\d{4})(\d{2})(\d+)/, "$2/$3/$1");

So to preserve what you are doing (adding a day to the date), one solution is:
var rDate = new Date();
rDate.setDate(rDate.getDate() + 1);
var printDate = rDate.getFullYear()+('0'+(rDate.getMonth()+1)).slice(-2)+('0'+(rDate.getDate())).slice(-2);
The advantage here is that rDate is always a real Date object, so you don't have to convert it back - you can just use it for any output format you wish.

The Date object in JavaScript has getFullYear, getMonth, and day methods, which means you can do:
If you had a function pad(num, digits) which pads a number with leading zeroes, you can have:
var str = pad(date.getFullYear(), 4) + pad(1+ date.getMonth(), 2) + pad(date.getDate(), 2)
From Pad a number with leading zeros in JavaScript on stackoverflow, you can get a pad functio:
function pad(n, width) {
n += '';
return n.length >= width ? n : new Array(width - n.length + 1).join('0') + n;
}

I don't think it's better, but another approach:
var d = new Date();
var datestr = [ d.getFullYear(), ('0' + (1+d.getMonth())).substr(-2), ("0" + d.getDate()).substr(-2) ].join('');
Two thing to clarify: getMonth() returns 0-based month number, hence the need to add 1. And the ("0" + number).substr(-2) is used to add leading zeroes to single digit numbers, because substr(-2) returns two last characters of a string.

Check if time is falling under specific timeframe

I have a variable that stores a time value.
var cabtime = ["09:30:00"];
Variable time value is in 24-hour clock. That means 02:30:0PM will come as 14:30:00.
I want to check if the variable time falls under 08:00AM to 10:00AM window. If yes then I'll do an action.
Any pointers in this regard?

You could parse the time into seconds since midnight using:
var cabtime = ["HH:MM:SS"] // in 24hr time
function parseTime (string) {
parts = string.split(':').map(x => parseInt(x))
seconds = parts[0] * 3600 + parts[1] * 60 + parts[0]
return seconds
}
Then you can parse the time and the upper/lower bounds, and test using:
time = parseTime(cabtime[0])
lower = parseTime('08:00:00')
upper = parseTime('10:00:00')
if (time >= lower && time <= upper) {
print('Inside the range')
}

You can solve it easily by converting your strings to Date objects and compare them than.
var cabtime = ["09:30"];
function checkTimeRange(time, from, to, reldate) {
if (undefined === reldate) {
reldate = '0000T'; // the date the time strings are related to
}
let dtime = new Date(reldate + time);
let dfrom = new Date(reldate + from);
let dto = new Date(reldate + to);
return dfrom <= dtime && dtime <= dto;
}
checkTimeRange(cabtime[0], '08:00', '10:00'); // returns true
If you have full dates (e.g. '2019-07-25T09:30:00') instead of just the clock time you should provide for the parameter `reldate' an empty string.
* update: changed the wrong date format to standard format
* update: changed the date format again to be more fancy

change time string of HH:mm am/pm to 24 hour time

I get a variable string like so:
8:45 am
And want, if it is pm, to convert it to 24 hour time. So that I can then drop the am/pm and use it with something else.
I can drop the am/pm quite easily like this:
function replaceEnds(string) {
string = string.replace("am", "");
string = string.replace("pm", "");
return string;
}
But of course if I do that, I don't know if the string is am or pm, so I don't know to add 12 hours on to the string to make it 24 hour.
Anyone know how I could resolve this? I absolutely cannot change the input that I get of the variable, it'll always be the hour (in 12 hour time), minutes, and am or pm.

Using moment.js:
moment(string, 'h:mm a').format('H:mm');
If you want to do it manually, this would be my solution:
function to24Hour(str) {
var tokens = /([10]?\d):([0-5]\d) ([ap]m)/i.exec(str);
if (tokens == null) { return null; }
if (tokens[3].toLowerCase() === 'pm' && tokens[1] !== '12') {
tokens[1] = '' + (12 + (+tokens[1]));
} else if (tokens[3].toLowerCase() === 'am' && tokens[1] === '12') {
tokens[1] = '00';
}
return tokens[1] + ':' + tokens[2];
}
The manual solution is harder to understand, is less flexible, is missing some error checking and needs unit tests. In general, you should usually prefer a well-tested popular library's solution, rather than your own (if a well-tested library is available).

Without using any additional JavaScript libraries:
/**
* #var amPmString - Time component (e.g. "8:45 PM")
* #returns - 24 hour time string
*/
function getTwentyFourHourTime(amPmString) {
var d = new Date("1/1/2013 " + amPmString);
return d.getHours() + ':' + d.getMinutes();
}
So for example:
getTwentyFourHourTime("8:45 PM"); // "20:45"
getTwentyFourHourTime("8:45 AM"); // "8:45"

In case you're looking for a solution that converts ANY FORMAT to 24 hours HH:MM correctly.
function get24hTime(str){
str = String(str).toLowerCase().replace(/\s/g, '');
var has_am = str.indexOf('am') >= 0;
var has_pm = str.indexOf('pm') >= 0;
// first strip off the am/pm, leave it either hour or hour:minute
str = str.replace('am', '').replace('pm', '');
// if hour, convert to hour:00
if (str.indexOf(':') < 0) str = str + ':00';
// now it's hour:minute
// we add am/pm back if striped out before
if (has_am) str += ' am';
if (has_pm) str += ' pm';
// now its either hour:minute, or hour:minute am/pm
// put it in a date object, it will convert to 24 hours format for us
var d = new Date("1/1/2011 " + str);
// make hours and minutes double digits
var doubleDigits = function(n){
return (parseInt(n) < 10) ? "0" + n : String(n);
};
return doubleDigits(d.getHours()) + ':' + doubleDigits(d.getMinutes());
}
console.log(get24hTime('6')); // 06:00
console.log(get24hTime('6am')); // 06:00
console.log(get24hTime('6pm')); // 18:00
console.log(get24hTime('6:11pm')); // 18:11
console.log(get24hTime('6:11')); // 06:11
console.log(get24hTime('18')); // 18:00
console.log(get24hTime('18:11')); // 18:11

I've use something similar to this
//time is an array of [hh] & [mm am/pm] (you can get this by time = time.split(":");
function MilitaryTime(time){
if(time[1].indexOf("AM")!=-1){
//its in the morning, so leave as is
return time;
}else if(time[0]!="12"){
//If it is beyond 12 o clock in the after noon, add twelve for military time.
time[0]=String(parseInt(time[0])+12);
return time;
}
else{
return time;
}
}
Once you get your time returned, you can alter the text in any way you want.

jQuery Format Time

I have a jQuery script that receives a string in milliseconds inside a parameter, like this:
params.tweetDate='77771564221';
What I need to do is to create a jQuery function that will be able to format this milliseconds string in a USA time, like 10.00 AM or 10.00 PM.
Is there a jQuery function that is able to do this?
Please help.
Thanks

There is Date object in pure javascript, no jQuery needed.
http://www.javascriptkit.com/jsref/date.shtml
Example:
var time = new Date(params.tweetDate),
h = time.getHours(), // 0-24 format
m = time.getMinutes();
// next just convert to AM/PM format (check if h > 12)

No, there's no jQuery function for this. You can use
JavaScript's own Date object, using the getHours() and getMinutes() functions, handling the AM/PM thing yourself (e.g., hours >= 12 is PM), padding out the minutes with a leading 0 if minutes is less than 10, etc. Also note that if hours is 0, you want to make it 12 (because when using the AM/PM style, you write midnight as "12:00 AM", not "0:00 AM").
DateJS, an add-on library that does a huge amount of date stuff (although sadly it's not actively maintained)
PrettyDate from John Resig (the creator of jQuery)
To use just about any of those, first you have to turn that "milliseconds" value into a Date object. If it's really a "milliseconds" value, then first you parse the string into a number via parseInt(str, 10) and then use new Date(num) to create the Date object representing that point in time. So:
var dt = new Date (parseInt(params.tweetDate, 10));
However, the value you've quoted, which you said is a milliseconds value, seems a bit odd — normally it's milliseconds since The Epoch (Jan 1, 1970), which is what JavaScript uses, but new Date(parseInt("77771564221", 10)) gives us a date in June 1972, long before Twitter. It's not seconds since The Epoch either (a fairly common Unix convention), because new Date(parseInt("77771564221", 10) * 1000) gives us a date in June 4434. So the first thing to find out is what that value actually represents, milliseconds since when. Then adjust it so it's milliseconds since The Epoch, and feed it into new Date() to get the object.

Here is a function for you:
function timeFormatter(dateTime){
var date = new Date(dateTime);
if (date.getHours()>=12){
var hour = parseInt(date.getHours()) - 12;
var amPm = "PM";
} else {
var hour = date.getHours();
var amPm = "AM";
}
var time = hour + ":" + date.getMinutes() + " " + amPm;
console.log(time);
return time;
}
You may call the function in any approach like:
var time = timeFormatter(parseInt("2345678998765"));

take a look at timeago: this is a jquery plugin used exactly for this purposes.

Using T.J.'s solution this is what I ended up with.
var date = new Date(parseInt("77771564221", 10));
var result = new Array();
result[0] = $.datepicker.formatDate('DD, M, d, yy', date);
result[1] = ' ';
if (date.getHours() > 12) {
result[2] = date.getHours() - 12;
} else if (date.getHours() == 0 ) {
result[2] = "12";
} else {
result[2] = date.getHours();
}
result[3] = ":"
result[4] = date.getMinutes();
if (date.getHours() > 12) {
result[5] = " pm";
} else {
result[5] = " am";
}
console.log(result.join(''));

Is there a way to increment time using javascript?

So I am storing times as '01:30:00'. I have a start time and a date time dropdown. I want the dropdown to be set to the start time + 1hr. Is there a way to add the time via javascript or jquery?
Here's my current code:
$(".start_time").change(function(){
$(".end_time").val($(this).val());
});

Try this:
find the selected index of the start time
bump it up by 2 to find your end time index (given that you've got half hour increments)
use the mod operator % to wrap back to index 0 or 1 (for 00:00 and 00:30 respectively)
$(".start_time").change(function(){
var sel =$(this).attr('selectedIndex');
var endIdx = (sel + 2) % 48; // 47 is 23:30, so 48 should go back to index 0
$(".end_time").attr('selectedIndex', endIdx);
});
Try it out on JSBin.

There are two separate problems here: the first is parsing out the time from your .start_time input, and the second is incrementing it to be an hour later.
The first is really a string-manipulation exercise. Once you have parsed out the pieces of the string, e.g. via a regex, you could either turn them into a Date instance and use setHours, or you could just manipulate the components as numbers and them reassemble them into a string in the format you desire.
An example of this might be as follows:
var TIME_PARSING_REGEX = /([0-9]{2}):([0-9]{2}):([0-9]{2})/;
function padToTwoDigits(number) {
return (number < 10 ? "0" : "") + number;
}
$(".start_time").change(function () {
var stringTime = $(this).val();
var regexResults = TIME_PARSING_REGEX.exec(stringTime);
var hours = parseInt(regexResults[1], 10);
var newHours = (hours + 1) % 24;
var newHoursString = padToTwoDigits(newHours);
var minutesString = regexResults[2];
var secondsString = regexResults[3];
var newTimeString = newHoursString + ":" + minutesString + ":" + secondsString;
$(".end_time").val(newTimeString);
});

Basic example...
var date = new Date();
var h = date.getHours() + 1;
var m = date.getMinutes();
var s = date.getSeconds();
alert('One hour from now: ' + h + ':' + m + ':' + s);
Demo: http://jsfiddle.net/fBaDM/2/

After you parse you date/time string, you can use methods such as .setHours in your date object (more info at Mozilla Developer Center).
I highly recommend the DateJS library for working with date and time. I'm sure it'll be very handy for you.
protip: try to avoid replacing JavaScript with "jQuery markup"; it's all JS, after all. :)