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I need to decrement a Javascript date by 1 day, so that it rolls back across months/years correctly. That is, if I have a date of 'Today', I want to get the date for 'Yesterday'.
It always seems to take more code than necessary when I do this, so I'm wondering if there's any simpler way.
What's the simplest way of doing this?
[Edit: Just to avoid confusion in an answer below, this is a JavaScript question, not a Java one.]
var d = new Date();
d.setDate(d.getDate() - 1);
console.log(d);
var today = new Date();
var yesterday = new Date().setDate(today.getDate() -1);
day.setDate(day.getDate() -1); //will be wrong
this will return wrong day. under UTC -03:00, check for
var d = new Date(2014,9,19);
d.setDate(d.getDate()-1);// will return Oct 17
Better use:
var n = day.getTime();
n -= 86400000;
day = new Date(n); //works fine for everything
getDate()-1 should do the trick
Quick example:
var day = new Date( "January 1 2008" );
day.setDate(day.getDate() -1);
alert(day);
origDate = new Date();
decrementedDate = new Date(origDate.getTime() - (86400 * 1000));
console.log(decrementedDate);
setDate(dayValue)
dayValue is an integer from 1 to 31, representing the day of the month.
from https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/Date/setDate
The behaviour solving your problem (and mine) seems to be out of specification range.
What seems to be needed are addDate(), addMonth(), addYear() ... functions.
Working with dates in JS can be a headache. So the simplest way is to use moment.js for any date operations.
To subtract one day:
const date = moment().subtract(1, 'day')
How can I convert a string to a date time object in javascript by specifying a format string?
I am looking for something like:
var dateTime = convertToDateTime("23.11.2009 12:34:56", "dd.MM.yyyy HH:mm:ss");
Use new Date(dateString) if your string is compatible with Date.parse(). If your format is incompatible (I think it is), you have to parse the string yourself (should be easy with regular expressions) and create a new Date object with explicit values for year, month, date, hour, minute and second.
I think this can help you: http://www.mattkruse.com/javascript/date/
There's a getDateFromFormat() function that you can tweak a little to solve your problem.
Update: there's an updated version of the samples available at javascripttoolbox.com
#Christoph Mentions using a regex to tackle the problem. Here's what I'm using:
var dateString = "2010-08-09 01:02:03";
var reggie = /(\d{4})-(\d{2})-(\d{2}) (\d{2}):(\d{2}):(\d{2})/;
var dateArray = reggie.exec(dateString);
var dateObject = new Date(
(+dateArray[1]),
(+dateArray[2])-1, // Careful, month starts at 0!
(+dateArray[3]),
(+dateArray[4]),
(+dateArray[5]),
(+dateArray[6])
);
It's by no means intelligent, just configure the regex and new Date(blah) to suit your needs.
Edit: Maybe a bit more understandable in ES6 using destructuring:
let dateString = "2010-08-09 01:02:03"
, reggie = /(\d{4})-(\d{2})-(\d{2}) (\d{2}):(\d{2}):(\d{2})/
, [, year, month, day, hours, minutes, seconds] = reggie.exec(dateString)
, dateObject = new Date(year, month-1, day, hours, minutes, seconds);
But in all honesty these days I reach for something like Moment
No sophisticated date/time formatting routines exist in JavaScript.
You will have to use an external library for formatted date output, "JavaScript Date Format" from Flagrant Badassery looks very promising.
For the input conversion, several suggestions have been made already. :)
Check out Moment.js. It is a modern and powerful library that makes up for JavaScript's woeful Date functions (or lack thereof).
Just for an updated answer here, there's a good js lib at http://www.datejs.com/
Datejs is an open source JavaScript Date library for parsing, formatting and processing.
var temp1 = "";
var temp2 = "";
var str1 = fd;
var str2 = td;
var dt1 = str1.substring(0,2);
var dt2 = str2.substring(0,2);
var mon1 = str1.substring(3,5);
var mon2 = str2.substring(3,5);
var yr1 = str1.substring(6,10);
var yr2 = str2.substring(6,10);
temp1 = mon1 + "/" + dt1 + "/" + yr1;
temp2 = mon2 + "/" + dt2 + "/" + yr2;
var cfd = Date.parse(temp1);
var ctd = Date.parse(temp2);
var date1 = new Date(cfd);
var date2 = new Date(ctd);
if(date1 > date2) {
alert("FROM DATE SHOULD BE MORE THAN TO DATE");
}
time = "2017-01-18T17:02:09.000+05:30"
t = new Date(time)
hr = ("0" + t.getHours()).slice(-2);
min = ("0" + t.getMinutes()).slice(-2);
sec = ("0" + t.getSeconds()).slice(-2);
t.getFullYear()+"-"+t.getMonth()+1+"-"+t.getDate()+" "+hr+":"+min+":"+sec
External library is an overkill for parsing one or two dates, so I made my own function using Oli's and Christoph's solutions. Here in central Europe we rarely use aything but the OP's format, so this should be enough for simple apps used here.
function ParseDate(dateString) {
//dd.mm.yyyy, or dd.mm.yy
var dateArr = dateString.split(".");
if (dateArr.length == 1) {
return null; //wrong format
}
//parse time after the year - separated by space
var spacePos = dateArr[2].indexOf(" ");
if(spacePos > 1) {
var timeString = dateArr[2].substr(spacePos + 1);
var timeArr = timeString.split(":");
dateArr[2] = dateArr[2].substr(0, spacePos);
if (timeArr.length == 2) {
//minutes only
return new Date(parseInt(dateArr[2]), parseInt(dateArr[1]-1), parseInt(dateArr[0]), parseInt(timeArr[0]), parseInt(timeArr[1]));
} else {
//including seconds
return new Date(parseInt(dateArr[2]), parseInt(dateArr[1]-1), parseInt(dateArr[0]), parseInt(timeArr[0]), parseInt(timeArr[1]), parseInt(timeArr[2]))
}
} else {
//gotcha at months - January is at 0, not 1 as one would expect
return new Date(parseInt(dateArr[2]), parseInt(dateArr[1] - 1), parseInt(dateArr[0]));
}
}
Date.parse() is fairly intelligent but I can't guarantee that format will parse correctly.
If it doesn't, you'd have to find something to bridge the two. Your example is pretty simple (being purely numbers) so a touch of REGEX (or even string.split() -- might be faster) paired with some parseInt() will allow you to quickly make a date.
Just to give my 5 cents.
My date format is dd.mm.yyyy (UK format) and none of the above examples were working for me. All the parsers were considering mm as day and dd as month.
I've found this library: http://joey.mazzarelli.com/2008/11/25/easy-date-parsing-with-javascript/
and it worked, because you can say the order of the fields like this:
>>console.log(new Date(Date.fromString('09.05.2012', {order: 'DMY'})));
Wed May 09 2012 00:00:00 GMT+0300 (EEST)
I hope that helps someone.
Moment.js will handle this:
var momentDate = moment('23.11.2009 12:34:56', 'DD.MM.YYYY HH:mm:ss');
var date = momentDate.;
You can use the moment.js library for this. I am using only to get time-specific output but you can select what kind of format you want to select.
Reference:
1. moment library: https://momentjs.com/
2. time and date specific functions: https://timestamp.online/article/how-to-convert-timestamp-to-datetime-in-javascript
convertDate(date) {
var momentDate = moment(date).format('hh : mm A');
return momentDate;
}
and you can call this method like:
this.convertDate('2020-05-01T10:31:18.837Z');
I hope it helps. Enjoy coding.
To fully satisfy the Date.parse convert string to format dd-mm-YYYY as specified in RFC822,
if you use yyyy-mm-dd parse may do a mistakes.
//Here pdate is the string date time
var date1=GetDate(pdate);
function GetDate(a){
var dateString = a.substr(6);
var currentTime = new Date(parseInt(dateString ));
var month =("0"+ (currentTime.getMonth() + 1)).slice(-2);
var day =("0"+ currentTime.getDate()).slice(-2);
var year = currentTime.getFullYear();
var date = day + "/" + month + "/" + year;
return date;
}
I would like to begin by saying i looked at multiple threads in this forum before posting. Wasnt able to find my solution :(
Issue: getting a NaN error when trying to find the difference between two dates with a timestamp from two textboxes.
The date format i'm using is DDMMYYYY HH:MM - 27/01/2015 00:00
code below.
thank you in advance for this super helpful forum :)
function stringToDate(s) {
var dateParts = s.split(' ')[0].split('-');
var timeParts = s.split(' ')[1].split(':');
var d = new Date(dateParts[0], --dateParts[1], dateParts[2]);
d.setHours(timeParts[0], timeParts[1], timeParts[2]);
return d;
}
function test() {
var a = textbox_1.value;
var b = textbox_2.value;
alert(stringToDate(a) - stringToDate(b));
}
Your date has / as separator but you are splitting the string on -. Change
var dateParts = s.split(' ')[0].split('-');
to
var dateParts = s.split(' ')[0].split('/');
Also, your time part has only hours and minutes, so there is no timeParts[2] present, just remove it from the setHours() call. Like this:
d.setHours(timeParts[0], timeParts[1])
Fiddle: http://jsfiddle.net/2evj59d1/
EDIT
Your code returns the difference in milliseconds. To convert it into date format just change
alert(stringToDate(a) - stringToDate(b));
to
alert(new Date(stringToDate(a) - stringToDate(b)));
The code is trying to parse a time in the format HH:MM:SS. Skip the third part:
d.setHours(timeParts[0], timeParts[1]);
You can convert the date into milliseconds, get the difference and get the date back.
Fiddle
JSCode:
var a = new Date();
a.setDate(15);
a = a.getTime();
var b = new Date();
b.setDate(32);
b = b.getTime();
var c = b - a;
var date = new Date(c);
alert(date.getDate() - 1);
for those who may have stumbled upon my post, i found my answer at the link below by user benjour.
How do I get the difference between two Dates in JavaScript?
What is best way to convert date from JavaScript string in format YYYYMMDD to JavaScript date format.
var from_date = document.getElementById('from_date').value;
var YYYY = from_date.substring(0,4);
var MM = from_date.substring(4,7);
var DD = from_date.substring(7,8);
var myDate = new Date( parseInt(YYYY,10), parseInt(MM,10)-1, parseInt(DD,10) );
note that the month provided to the date constructor is actual month number - 1.
edits: ok, there are some issues with your date part extraction- substring is probably the most awkward of javascript's sub-stringing methods (sub,substr,substring). And after testing I stand by the month value having to be 1 less than the actual number. Here is a fixed sample.
var from_date = "20101127"; //document.getElementById('from_date').value;
var YYYY = from_date.substring(0, 4);
var MM = from_date.substring(4, 6);
var DD = from_date.substring(6);
var myDate = new Date(parseInt(YYYY, 10), parseInt(MM, 10) - 1, parseInt(DD, 10));
alert(myDate); // should be november 27th 2010
It's easy, I struggled with the same question but came up with an easier way.
Create a hidden div tag and set the date into an attribute. then retrieve the attribute and use the sub string method to get something like Mar 01.
<div id="test" style="display:none;" date=""></div>
<script type="text/javascript">
var date = new Date();
document.getElementById('test').setAttribute('date',date);
var getdate = document.getElementById('test').getAttribute('date');
var newdate = getdate.substr(4,7);
alert(newdate);
</script>
That's all thanks!
check out my operating system: hypertos(dot)webege(dot)com
How can I convert a string to a date time object in javascript by specifying a format string?
I am looking for something like:
var dateTime = convertToDateTime("23.11.2009 12:34:56", "dd.MM.yyyy HH:mm:ss");
Use new Date(dateString) if your string is compatible with Date.parse(). If your format is incompatible (I think it is), you have to parse the string yourself (should be easy with regular expressions) and create a new Date object with explicit values for year, month, date, hour, minute and second.
I think this can help you: http://www.mattkruse.com/javascript/date/
There's a getDateFromFormat() function that you can tweak a little to solve your problem.
Update: there's an updated version of the samples available at javascripttoolbox.com
#Christoph Mentions using a regex to tackle the problem. Here's what I'm using:
var dateString = "2010-08-09 01:02:03";
var reggie = /(\d{4})-(\d{2})-(\d{2}) (\d{2}):(\d{2}):(\d{2})/;
var dateArray = reggie.exec(dateString);
var dateObject = new Date(
(+dateArray[1]),
(+dateArray[2])-1, // Careful, month starts at 0!
(+dateArray[3]),
(+dateArray[4]),
(+dateArray[5]),
(+dateArray[6])
);
It's by no means intelligent, just configure the regex and new Date(blah) to suit your needs.
Edit: Maybe a bit more understandable in ES6 using destructuring:
let dateString = "2010-08-09 01:02:03"
, reggie = /(\d{4})-(\d{2})-(\d{2}) (\d{2}):(\d{2}):(\d{2})/
, [, year, month, day, hours, minutes, seconds] = reggie.exec(dateString)
, dateObject = new Date(year, month-1, day, hours, minutes, seconds);
But in all honesty these days I reach for something like Moment
No sophisticated date/time formatting routines exist in JavaScript.
You will have to use an external library for formatted date output, "JavaScript Date Format" from Flagrant Badassery looks very promising.
For the input conversion, several suggestions have been made already. :)
Check out Moment.js. It is a modern and powerful library that makes up for JavaScript's woeful Date functions (or lack thereof).
Just for an updated answer here, there's a good js lib at http://www.datejs.com/
Datejs is an open source JavaScript Date library for parsing, formatting and processing.
var temp1 = "";
var temp2 = "";
var str1 = fd;
var str2 = td;
var dt1 = str1.substring(0,2);
var dt2 = str2.substring(0,2);
var mon1 = str1.substring(3,5);
var mon2 = str2.substring(3,5);
var yr1 = str1.substring(6,10);
var yr2 = str2.substring(6,10);
temp1 = mon1 + "/" + dt1 + "/" + yr1;
temp2 = mon2 + "/" + dt2 + "/" + yr2;
var cfd = Date.parse(temp1);
var ctd = Date.parse(temp2);
var date1 = new Date(cfd);
var date2 = new Date(ctd);
if(date1 > date2) {
alert("FROM DATE SHOULD BE MORE THAN TO DATE");
}
time = "2017-01-18T17:02:09.000+05:30"
t = new Date(time)
hr = ("0" + t.getHours()).slice(-2);
min = ("0" + t.getMinutes()).slice(-2);
sec = ("0" + t.getSeconds()).slice(-2);
t.getFullYear()+"-"+t.getMonth()+1+"-"+t.getDate()+" "+hr+":"+min+":"+sec
External library is an overkill for parsing one or two dates, so I made my own function using Oli's and Christoph's solutions. Here in central Europe we rarely use aything but the OP's format, so this should be enough for simple apps used here.
function ParseDate(dateString) {
//dd.mm.yyyy, or dd.mm.yy
var dateArr = dateString.split(".");
if (dateArr.length == 1) {
return null; //wrong format
}
//parse time after the year - separated by space
var spacePos = dateArr[2].indexOf(" ");
if(spacePos > 1) {
var timeString = dateArr[2].substr(spacePos + 1);
var timeArr = timeString.split(":");
dateArr[2] = dateArr[2].substr(0, spacePos);
if (timeArr.length == 2) {
//minutes only
return new Date(parseInt(dateArr[2]), parseInt(dateArr[1]-1), parseInt(dateArr[0]), parseInt(timeArr[0]), parseInt(timeArr[1]));
} else {
//including seconds
return new Date(parseInt(dateArr[2]), parseInt(dateArr[1]-1), parseInt(dateArr[0]), parseInt(timeArr[0]), parseInt(timeArr[1]), parseInt(timeArr[2]))
}
} else {
//gotcha at months - January is at 0, not 1 as one would expect
return new Date(parseInt(dateArr[2]), parseInt(dateArr[1] - 1), parseInt(dateArr[0]));
}
}
Date.parse() is fairly intelligent but I can't guarantee that format will parse correctly.
If it doesn't, you'd have to find something to bridge the two. Your example is pretty simple (being purely numbers) so a touch of REGEX (or even string.split() -- might be faster) paired with some parseInt() will allow you to quickly make a date.
Just to give my 5 cents.
My date format is dd.mm.yyyy (UK format) and none of the above examples were working for me. All the parsers were considering mm as day and dd as month.
I've found this library: http://joey.mazzarelli.com/2008/11/25/easy-date-parsing-with-javascript/
and it worked, because you can say the order of the fields like this:
>>console.log(new Date(Date.fromString('09.05.2012', {order: 'DMY'})));
Wed May 09 2012 00:00:00 GMT+0300 (EEST)
I hope that helps someone.
Moment.js will handle this:
var momentDate = moment('23.11.2009 12:34:56', 'DD.MM.YYYY HH:mm:ss');
var date = momentDate.;
You can use the moment.js library for this. I am using only to get time-specific output but you can select what kind of format you want to select.
Reference:
1. moment library: https://momentjs.com/
2. time and date specific functions: https://timestamp.online/article/how-to-convert-timestamp-to-datetime-in-javascript
convertDate(date) {
var momentDate = moment(date).format('hh : mm A');
return momentDate;
}
and you can call this method like:
this.convertDate('2020-05-01T10:31:18.837Z');
I hope it helps. Enjoy coding.
To fully satisfy the Date.parse convert string to format dd-mm-YYYY as specified in RFC822,
if you use yyyy-mm-dd parse may do a mistakes.
//Here pdate is the string date time
var date1=GetDate(pdate);
function GetDate(a){
var dateString = a.substr(6);
var currentTime = new Date(parseInt(dateString ));
var month =("0"+ (currentTime.getMonth() + 1)).slice(-2);
var day =("0"+ currentTime.getDate()).slice(-2);
var year = currentTime.getFullYear();
var date = day + "/" + month + "/" + year;
return date;
}