It amazes me that JavaScript's Date object does not implement an add function of any kind.
I simply want a function that can do this:
var now = Date.now();
var fourHoursLater = now.addHours(4);
function Date.prototype.addHours(h) {
// How do I implement this?
}
I would simply like some pointers in a direction.
Do I need to do string parsing?
Can I use setTime?
How about milliseconds?
Like this:
new Date(milliseconds + 4*3600*1000 /* 4 hours in ms */)?
This seems really hackish though - and does it even work?
JavaScript itself has terrible Date/Time API's. Nonetheless, you can do this in pure JavaScript:
Date.prototype.addHours = function(h) {
this.setTime(this.getTime() + (h*60*60*1000));
return this;
}
Date.prototype.addHours= function(h){
this.setHours(this.getHours()+h);
return this;
}
Test:
alert(new Date().addHours(4));
The below code will add 4 hours to a date (example, today's date):
var today = new Date();
today.setHours(today.getHours() + 4);
It will not cause an error if you try to add 4 to 23 (see the documentation):
If a parameter you specify is outside of the expected range, setHours() attempts to update the date information in the Date object accordingly
It is probably better to make the addHours method immutable by returning a copy of the Date object rather than mutating its parameter.
Date.prototype.addHours= function(h){
var copiedDate = new Date(this.getTime());
copiedDate.setHours(copiedDate.getHours()+h);
return copiedDate;
}
This way you can chain a bunch of method calls without worrying about state.
The version suggested by kennebec will fail when changing to or from DST, since it is the hour number that is set.
this.setUTCHours(this.getUTCHours()+h);
will add h hours to this independent of time system peculiarities.
Jason Harwig's method works as well.
Get a date exactly two hours from now, in one line.
You need to pass milliseconds to new Date.
let expiryDate = new Date(new Date().setHours(new Date().getHours() + 2));
or
let expiryDate2 = new Date(Date.now() + 2 * (60 * 60 * 1000) );
let nowDate = new Date();
let expiryDate = new Date(new Date().setHours(new Date().getHours() + 2));
let expiryDate2 = new Date(Date.now() + 2 * (60 * 60 * 1000) );
console.log('now', nowDate);
console.log('expiry', expiryDate);
console.log('expiry 2', expiryDate2);
You can use the Moment.js library.
var moment = require('moment');
foo = new moment(something).add(10, 'm').toDate();
I also think the original object should not be modified. So to save future manpower here's a combined solution based on Jason Harwig's and Tahir Hasan answers:
Date.prototype.addHours= function(h){
var copiedDate = new Date();
copiedDate.setTime(this.getTime() + (h*60*60*1000));
return copiedDate;
}
If you would like to do it in a more functional way (immutability) I would return a new date object instead of modifying the existing and I wouldn't alter the prototype but create a standalone function. Here is the example:
//JS
function addHoursToDate(date, hours) {
return new Date(new Date(date).setHours(date.getHours() + hours));
}
//TS
function addHoursToDate(date: Date, hours: number): Date {
return new Date(new Date(date).setHours(date.getHours() + hours));
}
let myDate = new Date();
console.log(myDate)
console.log(addHoursToDate(myDate,2))
There is an add in the Datejs library.
And here are the JavaScript date methods. kennebec wisely mentioned getHours() and setHours();
Check if it’s not already defined. Otherwise, define it in the Date prototype:
if (!Date.prototype.addHours) {
Date.prototype.addHours = function(h) {
this.setHours(this.getHours() + h);
return this;
};
}
This is an easy way to get an incremented or decremented data value.
const date = new Date()
const inc = 1000 * 60 * 60 // an hour
const dec = (1000 * 60 * 60) * -1 // an hour
const _date = new Date(date)
return new Date(_date.getTime() + inc)
return new Date(_date.getTime() + dec)
Another way to handle this is to convert the date to unixtime (epoch), then add the equivalent in (milli)seconds, then convert it back. This way you can handle day and month transitions, like adding 4 hours to 21, which should result in the next day, 01:00.
SPRBRN is correct. In order to account for the beginning/end of the month and year, you need to convert to Epoch and back.
Here's how you do that:
var milliseconds = 0; //amount of time from current date/time
var sec = 0; //(+): future
var min = 0; //(-): past
var hours = 2;
var days = 0;
var startDate = new Date(); //start date in local time (we'll use current time as an example)
var time = startDate.getTime(); //convert to milliseconds since epoch
//add time difference
var newTime = time + milliseconds + (1000*sec) + (1000*60*min) + (1000*60*60*hrs) + (1000*60*60*24*days);
var newDate = new Date(newTime); //convert back to date; in this example: 2 hours from right now
Or do it in one line (where variable names are the same as above:
var newDate =
new Date(startDate.getTime() + millisecond +
1000 * (sec + 60 * (min + 60 * (hours + 24 * days))));
For a simple add/subtract hour/minute function in JavaScript, try this:
function getTime (addHour, addMin){
addHour = (addHour ? addHour : 0);
addMin = (addMin ? addMin : 0);
var time = new Date(new Date().getTime());
var AM = true;
var ndble = 0;
var hours, newHour, overHour, newMin, overMin;
// Change form 24 to 12 hour clock
if(time.getHours() >= 13){
hours = time.getHours() - 12;
AM = (hours>=12 ? true : false);
}else{
hours = time.getHours();
AM = (hours>=12 ? false : true);
}
// Get the current minutes
var minutes = time.getMinutes();
// Set minute
if((minutes + addMin) >= 60 || (minutes + addMin) < 0){
overMin = (minutes + addMin) % 60;
overHour = Math.floor((minutes + addMin - Math.abs(overMin))/60);
if(overMin < 0){
overMin = overMin + 60;
overHour = overHour-Math.floor(overMin/60);
}
newMin = String((overMin<10 ? '0' : '') + overMin);
addHour = addHour + overHour;
}else{
newMin = minutes + addMin;
newMin = String((newMin<10 ? '0' : '') + newMin);
}
// Set hour
if((hours + addHour >= 13) || (hours + addHour <= 0)){
overHour = (hours + addHour) % 12;
ndble = Math.floor(Math.abs((hours + addHour)/12));
if(overHour <= 0){
newHour = overHour + 12;
if(overHour == 0){
ndble++;
}
}else{
if(overHour == 0){
newHour = 12;
ndble++;
}else{
ndble++;
newHour = overHour;
}
}
newHour = (newHour<10 ? '0' : '') + String(newHour);
AM = ((ndble + 1) % 2 === 0) ? AM : !AM;
}else{
AM = (hours + addHour == 12 ? !AM : AM);
newHour = String((Number(hours) + addHour < 10 ? '0': '') + (hours + addHour));
}
var am = (AM) ? 'AM' : 'PM';
return new Array(newHour, newMin, am);
};
This can be used without parameters to get the current time:
getTime();
Or with parameters to get the time with the added minutes/hours:
getTime(1, 30); // Adds 1.5 hours to current time
getTime(2); // Adds 2 hours to current time
getTime(0, 120); // Same as above
Even negative time works:
getTime(-1, -30); // Subtracts 1.5 hours from current time
This function returns an array of:
array([Hour], [Minute], [Meridian])
If you need it as a string, for example:
var defaultTime: new Date().getHours() + 1 + ":" + new Date().getMinutes();
I think this should do the trick
var nextHour = Date.now() + 1000 * 60 * 60;
console.log(nextHour)
You can even format the date in desired format using the moment function after adding 2 hours.
var time = moment(new Date(new Date().setHours(new Date().getHours() + 2))).format("YYYY-MM-DD");
console.log(time);
A little messy, but it works!
Given a date format like this: 2019-04-03T15:58
//Get the start date.
var start = $("#start_date").val();
//Split the date and time.
var startarray = start.split("T");
var date = startarray[0];
var time = startarray[1];
//Split the hours and minutes.
var timearray = time.split(":");
var hour = timearray[0];
var minute = timearray[1];
//Add an hour to the hour.
hour++;
//$("#end_date").val = start;
$("#end_date").val(""+date+"T"+hour+":"+minute+"");
Your output would be: 2019-04-03T16:58
The easiest way to do it is:
var d = new Date();
d = new Date(d.setHours(d.getHours() + 2));
It will add 2 hours to the current time.
The value of d = Sat Jan 30 2021 23:41:43 GMT+0500 (Pakistan Standard Time).
The value of d after adding 2 hours = Sun Jan 31 2021 01:41:43 GMT+0500 (Pakistan Standard Time).
I have developed a website , where end users are in Toronto . I have set timezone for them but it is showing wrong date. ahead one day from Toronto .
It shows correct time at some time but at the end of day it shows one day ahead time .. i don't know why is it doing it ?
function calcTime(city, offset) {
// create Date object for current location
d = new Date();
utc = d.getTime() + (d.getTimezoneOffset() * 60000);
// create new Date object for different city
// using supplied offset
nd = new Date(utc + (3600000*offset));
// return time as a string
return nd;
}
function getdatetime() {
var date =calcTime('Toronto', '-8');
var currentDate = date.toISOString().slice(0,10);
var currentTime = date.getHours() + ':' + (date.getMinutes()<10?'0':'') + date.getMinutes() ;
document.getElementById('datetime').value = (currentDate+" " + currentTime);
}
Last Entries:
2020-01-16 16:44
2020-01-16 16:42
2020-01-16 16:41 //from here
2020-01-15 15:25
2020-01-15 15:23
2020-01-15 15:22
Try the below code.
function getdatetime() {
let timezone = new Date().toLocaleString("en-US", {timeZone: "America/Toronto"});
let date = new Date(timezone);
var currentDate = date.toISOString().slice(0,10);
var currentTime = date.getHours() + ':' + (date.getMinutes()<10?'0':'') + date.getMinutes() ;
console.log(date);
}
getdatetime();
I wrote the following code in JS
var d = new Date(2019, 9, 14);
var currentTime = d.getTime();
var daysToAdd = 3;
var secondsInDay = 86400;
var d = new Date(currentTime + daysToAdd*secondsInDay);
var year = d.getFullYear();
var month = ("0" + (d.getMonth())).slice(-2);
var day = ("0" + d.getDate()).slice(-2);
console.log('result in Y-M-D is: ' + year + '-' + month + '-' + day);
This outputs to result in Y-M-D is: 2019-09-14
What am I doing wrong here? How to I change this to output result in Y-M-D is: 2019-09-17 , which I originally intended to do
This happens because on this code
new Date(currentTime + daysToAdd*secondsInDay);
secondsInDay is a representation in seconds, and currentTime is represented in ms. If you multiply your secondsInDay by 1000 (to get the equivalent value in ms) you will get the desired date.
Instead of
var d = new Date(currentTime + daysToAdd*secondsInDay);
you can use
d.setDate(new Date().getDate()+3);
Youre problem is that the constructor of the date object uses MILISECONDS to calculate the date, and you're using SECONDS to add that 3 extra days. Instead of 86400 (seconds) you need to use the value 86400000 (miliseconds).
Goodbye!
You can add the number of days directly to d.getDate()
var d = new Date(2019, 9, 14);
var daysToAdd = 3;
var new_day = d.getDate() + daysToAdd;
var new_d = new Date(d.getFullYear(), d. getMonth(), new_day);
alert('result in Y-M-D is: ' + new_d.getFullYear() + '-' + new_d. getMonth() + '-' + new_day);
I want to add 30 minutes and then one hour to my variable which i already have my own date
var initialDate = '10:00';
So
if (some condition){
// i add 30 minutes ->10:30
}elseif(another condition){
// i add 1hour ->11:00
}
I tried this but doesn't work
var initialDate = '10:00';
var theAdd = new Date(initialDate);
var finalDate = theAdd.setMinutes(theAdd.getMinutes() + 30);
If I understand you correctly, the following will help you.
You need to add momentjs dependency via script tag and you can Parse, validate, manipulate, and display dates in JavaScript.
You can find more documentation regarding this in momentjs website
console.log(moment.utc('10:00','hh:mm').add(1,'hour').format('hh:mm'));
console.log(moment.utc('10:00','hh:mm').add(30,'minutes').format('hh:mm'));
<script src="https://momentjs.com/downloads/moment-with-locales.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
var theAdd = new Date();
// Set Hours, minutes, secons and miliseconds
theAdd.setHours(10, 00, 00, 000);
if (some condition) {
// add 30 minutes --> 10:30
theAdd.setMinutes(theAdd.getMinutes() + 30);
}
elseif (some condition) {
// add 1 hour --> 11:00
theAdd.setHours(theAdd.getHours() + 1);
}
Then you print the var theAdd to obtain the date and time.
To obtain just the time:
theAdd.getHours() + ":" + theAdd.getMinutes();
This should do the job. Dates need a year and month in their constructor, and you have to specify larger units of time if you specify and smaller ones, so it needs a day as well. Also, you have to pass in the hours and minutes separately. See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date.
var initialDate = '10:00';
var theAdd = new Date(1900,0,1,initialDate.split(":")[0],initialDate.split(":")[1]);
if(30 min condition){
theAdd.setMinutes(theAdd.getMinutes() + 30);
} else if (1 hour condition){
theAdd.setHours(theAdd.getHours() + 1);
}
console.log(theAdd.getHours()+":"+theAdd.getMinutes());
Here is a javascript function that will add minutes to hh:mm time string.
function addMinutes(timeString, addMinutes) {
if (!timeString.match(/^([0-9]|0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]$/))
return null;
var timeSplit = timeString.split(':');
var hours = parseInt(timeSplit[0]);
var minutes = parseInt(timeSplit[1]) + parseInt(addMinutes);
hours += Math.floor(minutes / 60);
while (hours >= 24) {
hours -= 24;
}
minutes = minutes % 60;
return ('0' + hours).slice(-2) + ':' + ('0' +minutes).slice(-2);
}
I use Date object to create time in my Javascript code and it should be formated like so : 08:04:21. This is how I tried to do it:
$('#time').click(function(){
var currentTime = new Date();
var Time=currentTime.getHours() + ":"
+ currentTime.getMinutes() + ":"
+ currentTime.setSeconds(currentTime.getSeconds() + 60);
console.log(Time);
$(this).val(Time);
});
But when Time is logged in console string looks like this 8:1:1467844916075. Same happens when i try this:
var Time=currentTime.getHours() + ":"
+ currentTime.setMinutes(currentTime.getMinutes() + 1) + ":"
+ currentTime.getSeconds();
It bring out similar result : 8:1467844916075:3. I even tried this answer: javascript add one minute to time object
$('#time').click(function(){
var currentTime = new Date();
var Time = currentTime.setTime(currentTime.getTime() + 1000 * 60);
console.log(Time);
$(this).val(Time);
});
But Time in this case looks like this: 1467785566719. Any idea how to get human readable current time(not date) plus one minute?
You can check this:
Date.getTime() returns you the number of milliseconds since 1970/01/01.
So just grab it and add 1 minute to it to form new milliseconds count for new date.
var d = new Date();
var millisecondssince1970 = d.getTime();
var newMillisec = millisecondssince1970 + (1000 * 60);
var newDate = new Date(newMillisec);
console.log(newDate.getHours() + ":"
+ newDate.getMinutes() + ":"
+ newDate.getSeconds());
Please try this,
var currentTime = new Date();
var Time = currentTime.setTime(currentTime.getTime() + 1000 * 60);
console.log(Time);
var date = new Date(Time);
// Hours part from the timestamp
var hours = date.getHours();
// Minutes part from the timestamp
var minutes = "0" + date.getMinutes();
// Seconds part from the timestamp
var seconds = "0" + date.getSeconds();
// Will display time in 10:30:23 format
var formattedTime = hours + ':' + minutes.substr(-2) + ':' + seconds.substr(-2);
console.log(formattedTime);
Here is working example https://jsfiddle.net/oa7j3krs/2/
$('#time').click(function(){
var d = new Date($.now()+60*1000); // current time + 60s
$(this).val(d.getHours()+':'+d.getMinutes()+':'+d.getSeconds());
});
Anyway, I found a way to do this. Maybe it's not the best but it will do the job.
$('#time').click(function(){
var currentTime = new Date();
var addOneMinute = currentTime.getMinutes();
addOneMinute=parseInt(addOneMinute) + 1;
var Time=currentTime.getHours() + ":"
+ addOneMinute + ":"
+ currentTime.getSeconds();
console.log(Time);
$(this).val(Time);
});