Increase number twice a week - javascript

How would you increase a a number on a webpage twice a week on specific days and times?
For example the webpage would read:
"2 Apples"
However every Tuesday & Thursday at 9:00pm the number should increase by two.
So by Friday the number should have increased to 6 "Apples"
What's a simple way to increment this in Javascript, php or Jquery?

As it was mentionned in the comments, I advise you to use a cron to handle this.
First, you have to store your value somewhere (file, databse, ...). Then, you should create a cron job, that runs a code that increase and update your value at the given days of the week.
Some help about crons : https://en.wikipedia.org/wiki/Cron#Examples
I would add this post about cron and php : Executing a PHP script with a CRON Job
Hope it helps

Here a Javascript version, you can pass it the date it should start counting, the date you want to know the ammount of apples of, the days of the week apples will be added, the hours of the day the updat will take place and the ammount of apples that will be added on each of these dates.
Date.prototype.addDays = function (days) {
var result = new Date(this);
result.setDate(result.getDate() + days);
return result;
}
Date.prototype.addHours = function (hours) {
var result = new Date(this);
result.setHours(result.getHours() + hours);
return result;
}
function getApples(startdate, date, updateDays, updateTime, applesPerUpdate) {
var startDay = startdate.getDay();
var firstUpdateDate;
for(day of updateDays) {
if (day >= startDay) {//assumes startdate has no time added
firstUpdateDate = startdate.addDays(day - startDay).addHours(updateTime);
break;
}
}
if (!firstUpdateDate)
firstUpdateDate = startdate.addDays(7 - (startDay - updateDays[0])).addHours(updateTime);
var updateDaysReverse = updateDays.slice(0).reverse();//clones the array
var dateDay = date.getDay();
var lastUpdateDate;
for(day of updateDaysReverse) {
if (day < dateDay || day == dateDay && date.getHours() > updateTime) {
lastUpdateDate = date.addDays(day - dateDay);
break;
}
}
if (!lastUpdateDate)
lastUpdateDate = date.addDays(updateDaysReverse[0] - (7 + dateDay));
lastUpdateDate = new Date(Date.UTC(1900 + lastUpdateDate.getYear(), lastUpdateDate.getMonth(), lastUpdateDate.getDate(), updateTime, 0, 0, 0));
var secs = Math.trunc((lastUpdateDate - firstUpdateDate));
if (secs < 0) return 0;
var dayDiffs = [];
for(day of updateDays)
dayDiffs.push(day - updateDays[0]);
var weeks = Math.trunc(secs / 604800000);
var days = Math.trunc((secs % 604800000) / 86400000);
var apples = weeks * updateDays.length;
for(diff of dayDiffs)
{
if (diff <= days)
apples++;
else
break;
}
return apples * applesPerUpdate;
}
// important, day and month is zero-based
var startDate = new Date(Date.UTC(2016, 01, 07, 0, 0, 0, 0));
var updateDays = [2, 4];// 0 = sunday , have to be in order and must be 0 <= x < 7
var updateTime = 9;
console.log(getApples(startDate, new Date(), updateDays, updateTime, 2));
Was more coplicated than I thaught, and i havn't testet it much, so there may be bugs.
Here is a plunker to play with the values.

Related

How to get the public holidays of each year using Laravel/JavaScript?

I'm beginner in web programming, and now I'm trying to get the number of days between two dates excluding the weekends and the public holidays of each year of our country.
I want to get a list of holidays of my own specific year. Like I pass the year 2021, then it will return all the holidays of 2021, similarly, if I pass 2022, then it will return 2022.
By using the JavaScript, I calculated the difference between two dates excluding the weekends.
The following code describes the difference between two dates excluding the weekends.
function getBusinessDateCount (startDate, endDate) {
var elapsed, daysBeforeFirstSaturday, daysAfterLastSunday;
var ifThen = function (a, b, c) {
return a == b ? c : a;
};
elapsed = endDate - startDate; elapsed /= 86400000;
daysBeforeFirstSunday = (7 - startDate.getDay()) % 7; daysAfterLastSunday = endDate.getDay();
elapsed -= (daysBeforeFirstSunday + daysAfterLastSunday);
elapsed = (elapsed / 7) * 5;
elapsed += ifThen(daysBeforeFirstSunday - 1, -1, 0) + ifThen(daysAfterLastSunday, 6, 5);
return Math.ceil(elapsed); }
$(document).ready(function(){
$(document).on('change','#date2',function (evt) {
let start = document.querySelector('#date1').value,
end = document.querySelector('#date2').value,
result = getBusinessDateCount(new Date(start),
new Date(end));
document.getElementById("days").value = result+ " Jours";
}); });
Now, I'm stuck in how I can add also the public holidays of each year of our country and get the number between two dates excluding weekends and public holidays.
If you have any ideas, please help
You have date1 and date2. date1 was in year1 and date2 was in year2.
year2 >= year1
Even though it's possible that some holidays are not celebrated every year or, they were introduced between your two dates, for the sake of simplicity I will assume that any holiday is celebrated each year.
So, assuming there are n holidays celebrated yearly, you also know that for
year1 < y < year2
years, there are n holidays. So:
let holidays = 0;
if (year2 > year1 + 2) {
holidays = (year2 - year1 - 1) * n;
}
Now, you will need to loop your holidays and compare their months and date against the months and date of date1 and date2, so, if they are later than date1 then add them and if they are earlier than date2 then add them (if both criterias are fulfilled, add them twice):
let month1 = date1.getMonth();
let day1 = date1.getDate();
let month2 = date2.getMonth();
let day2 = date2.getDate();
for (let holiday of holidayArray) {
let m = holiday.getMonth();
let d = holiday.getDate();
if ((month1 < m) || ((month1 === m) && (day1 <= d))) {
holidays++;
}
if ((month2 > m) || ((month2 === m) && (day2 >= d))) {
holidays++;
}
}
Now, let's focus on the weekends, luckily this part was already solved at SO at How to determine number Saturdays and Sundays comes between two dates in java script
function countWeekendDays( d0, d1 )
{
var ndays = 1 + Math.round((d1.getTime()-d0.getTime())/(24*3600*1000));
var nsaturdays = Math.floor( (d0.getDay()+ndays) / 7 );
return 2*nsaturdays + (d0.getDay()==0) - (d1.getDay()==6);
}
At the result of countWeekendDays to holidays and that should solve the problem.

Javascript to count the number of days for a specific month between two dates [duplicate]

This question already has answers here:
How to calculate number of days between two dates?
(42 answers)
Closed last month.
I am new to javascript.
I have specific month columns (9/30/2022, 10/31/2022,11/30/2022). I have a contract with a start date and end date (spanning multiple months).
I need to determine the number of days the contract was active for a specific month column.
Example:
Contact Start Date: 09/15/2022
Contract End Date: 10/24/2022
Number of days the contract was active in Sept 2022 is 16.
I found the code below that gives me the contract period broken down for each month (i.e.) **9 - 17; 10 - 23; **
Thank you in advance for any assistance.
I found this code
function getDays() {
var dropdt = new Date(document.getElementById("arr").value);
var pickdt = new Date(document.getElementById("dep").value);
var result = "";
for (var year = dropdt.getFullYear(); year <= pickdt.getFullYear(); year++) {
var firstMonth = (year == dropdt.getFullYear()) ? dropdt.getMonth() : 0;
var lastMonth = (year == pickdt.getFullYear()) ? pickdt.getMonth() : 11;
for (var month = firstMonth; month <= lastMonth; month++) {
var firstDay = (year === dropdt.getFullYear() && month === firstMonth) ? dropdt.getDate() : 1;
var lastDay = (year === pickdt.getFullYear() && month === lastMonth) ? pickdt.getDate() : 0;
var lastDateMonth = (lastDay === 0) ? (month + 1) : month
var firstDate = new Date(year, month, firstDay);
var lastDate = new Date(year, lastDateMonth, lastDay);
result += (month + 1) + " - " + parseInt((lastDate - firstDate) / (24 * 3600 * 1000) + 1) + "; ";
}
}
return result;
}
function cal() {
if (document.getElementById("dep")) {
document.getElementById("number-of-dates").value = getDays();
}
Calculate
`
The following snippet will generate an object res with the keys being zero-based month-indexes ("8" is for September, "9" for October, etc.) and the values are the number of days for each of these months:
const start=new Date("2022-09-15");
const end=new Date("2022-11-24");
let nextFirst=new Date(start.getTime()), month, days={};
do {
month=nextFirst.getMonth();
nextFirst.setMonth(month+1);nextFirst.setDate(1);
days[month]=Math.round(((nextFirst<end?nextFirst:end)-start)/86400000);
start.setTime(nextFirst.getTime());
} while(nextFirst<end)
console.log(days);
This can be extended into a more reliable function returning a year-month combination:
function daysPerMonth(start,end){
let nextFirst=new Date(start.getTime()), year, month, days={};
do {
year=nextFirst.getFullYear();
month=nextFirst.getMonth();
nextFirst.setMonth(month+1);nextFirst.setDate(1);
days[`${year}-${String(1+month).padStart(2,"0")}`]=Math.round(((nextFirst<end?nextFirst:end)-start)/86400000);
start.setTime(nextFirst.getTime());
} while(nextFirst<end)
return days;
}
[["2022-09-15","2022-11-24"],["2022-11-29","2023-02-04"]].forEach(([a,b])=>
console.log(daysPerMonth(new Date(a),new Date(b))));
Managing and calculating dates, times, and date-times are notoriously finicky in javascript and across browsers. Rather than trying to define your own logic for this use the famous Moment.js library.
In particular to calculate the length between two dates you can utilize the diff function between two moments
var a = moment([2007, 0, 29]);
var b = moment([2007, 0, 25]);
var diff = a.diff(b, 'days') // 1
console.log(diff);
<script src="https://momentjs.com/downloads/moment.js"></script>
The supported measurements are years, months, weeks, days, hours, minutes, and seconds.

Calculate days excluding weekend and holiday in JavaScript

I am trying to write a code where total days will be counted excluding weekends and custom defined holiday. I searched through stackoverflow and adobe forum to find a solution and came with below code.
If public holiday falls in a working day (Saturday-Wednesday) it is excluding from calculation.
My problem is that if public holiday falls in weekend (Thursday-Friday), it is deducting for both (holiday & weekend). Suppose leave duration is 18/09/2018-22/09/2018, total count 2 days is showing in place of 3. Again for 17/10/2018-21/10/2018, total count 1 day is showing in place of 3 days.
Any help or any idea to solve the problem would be great!
Regards
//Thursday and Friday will be excluded as weekend.
var start = this.getField("From").value;
// get the start date value
var end = this.getField("To").value;
var end = util.scand("dd/mm/yyyy H:MM:SS", end + " 0:00:00");
var start =util.scand("dd/mm/yyyy H:MM:SS", start + " 0:00:00");
event.value = dateDifference(start, end);
function dateDifference(start, end) {
// Copy date objects so don't modify originals
var s = new Date(+start);
var e = new Date(+end);
// Set time to midday to avoid daylight saving and browser quirks
s.setHours(12,0,0,0);
e.setHours(12,0,0,0);
// Get the difference in whole days
var totalDays = Math.round((e - s) / 8.64e7);
// Get the difference in whole weeks
var wholeWeeks = totalDays / 7 | 0;
// Estimate business days as number of whole weeks * 5
var days = wholeWeeks * 5;
// If not even number of weeks, calc remaining weekend days
if (totalDays % 7) {
s.setDate(s.getDate() + wholeWeeks * 7);
while (s < e) {
s.setDate(s.getDate() + 1);
// If day isn't a Thursday or Friday, add to business days
if (s.getDay() != 4 && s.getDay() != 5) {
++days;
}
}
}
var hdayar = ["2018/02/21","2018/03/17","2018/03/26","2018/04/14","2018/05/01","2018/08/15","2018/09/2 1","2018/10/18","2018/10/19","2018/12/16","2018/12/25"];
//test for public holidays
var phdays = 0;
for (var i = 0; i <hdayar.length; i++){
if ((Date.parse(hdayar[i]) >= Date.parse(start)) && (Date.parse(hdayar[i]) <= Date.parse(end))) {phdays ++;}}
return days-phdays + 1;
}
You should use a library for this rather than reinventing the wheel.
But if you want to do it yourself you could use .getDay to check if the public holidays are on a weekend.
var weekend = [4, 5], // for Thursday, Friday
holDate, holDay;
for (var i = 0; i < hdayar.length; i++){
holDate = Date.parse(hdayar[i]);
holDay = new Date(holDate).getDay()
if (weekend.indexOf(holDay) == -1 && holDate >= Date.parse(start) && holDate <= Date.parse(end)) {
phdays ++;
}
}
phdays will now contain the number of non-weekend public holidays within the range.
Just have the same requirement and this is the my work around.Hope it helps other
var holiday = ["4/18/2019", "4/19/2019", "4/20/2019", "4/25/2019", "4/26/2019"];
var startDate = new Date();
var endDate = new Date(startDate.setDate(startDate.getDate() + 1));
for (i = 0; i < holiday.length; i++) {
var date = endDate.getDate();
var month = endDate.getMonth() + 1; //Months are zero based
var year = endDate.getFullYear();
if ((month + '/' + date + '/' + year) === (holiday[i])) {
endDate = new Date(endDate.setDate(endDate.getDate() + 1));
if (endDate.getDay() == 6) {
endDate = new Date(endDate.setDate(endDate.getDate() + 2));
} else if (endDate.getDay() == 0) {
endDate = new Date(endDate.setDate(endDate.getDate() + 1));
}
}
}
Here, end date gives you next working day.Here,I'm ignoring current day and start comparing from Next day whether it's holiday or weekend.You can customize dateTime as per your requirement (month + '/' + date + '/' + year).Careful whenever you compares two dates with each other. Because it looks same but actually it's not.So customize accordingly.

How to exclude weekends between two dates using Moment.js

I am trying to exclude weekends in my JavaScript code. I use moment.js and having difficulty choosing the right variable for 'days'.
So far I have thought that I need to exclude day 6 (saturday) and day 0 (sunday) by changing the weekday variable to count from day 1 to day 5 only. But not sure how it changes.
My jsfiddle is shown here: FIDDLE
HTML:
<div id="myContent">
<input type="radio" value="types" class="syncTypes" name="syncTypes"> <td><label for="xshipping.xshipping1">Free Shipping: (<span id="fsv1" value="5">5</span> to <span id="fsv2" value="10">10</span> working days)</label> </td><br>
<div id="contacts" style="display:none;border:1px #666 solid;padding:3px;top:15px;position:relative;margin-bottom:25px;">
Contacts
</div>
<input type="radio" value="groups" class="syncTypes" name="syncTypes"> <td><label for="xshipping.xshipping2">Express Shipping: (<span id="esv1" value="3">3</span> to <span id="esv2" value="4">4</span> working days)</label> </td>
<div id="groups" style="display:none;border:1px #666 solid;padding:3px;top:15px;position:relative">
Groups
</div>
</div>
JavaScript:
var a = 5; //Free shipping between a
var b = 10;//and b
var c = 3;//Express shipping between c
var d = 4;//and d
var now = moment();
var f = "Your item will be delivered between " + now.add("days",a).format("Do MMMM") + " and " + now.add("days",b).format("Do MMMM");
var g = "Your item will be delivered between " + now.add("days".c).format("Do MMMM") + " and " + now.add("days",d).format("Do MMMM");
var h = document.getElementById('contacts');
h.innerHTML = g
var i = document.getElementById('groups');
i.innerHTML = f
$(function() {
$types = $('.syncTypes');
$contacts = $('#contacts');
$groups = $('#groups');
$types.change(function() {
$this = $(this).val();
if ($this == "types") {
$groups.slideUp(300);
$contacts.delay(200).slideDown(300);
}
else if ($this == "groups") {
$contacts.slideUp(300);
$groups.delay(200).slideDown(300);
}
});
});
Here you go!
function addWeekdays(date, days) {
date = moment(date); // use a clone
while (days > 0) {
date = date.add(1, 'days');
// decrease "days" only if it's a weekday.
if (date.isoWeekday() !== 6 && date.isoWeekday() !== 7) {
days -= 1;
}
}
return date;
}
You call it like this
var date = addWeekdays(moment(), 5);
I used .isoWeekday instead of .weekday because it doesn't depend on the locale (.weekday(0) can be either Monday or Sunday).
Don't subtract weekdays, i.e addWeekdays(moment(), -3) otherwise this simple function will loop forever!
Updated JSFiddle http://jsfiddle.net/Xt2e6/39/ (using different momentjs cdn)
Those iteration looped solutions would not fit my needs.
They were too slow for large numbers.
So I made my own version:
https://github.com/leonardosantos/momentjs-business
Hope you find it useful.
https://github.com/andruhon/moment-weekday-calc plugin for momentJS might be helpful for similar tasks
It does not solves the exact problem, but it is able to calculate specific weekdays in the range.
Usage:
moment().isoWeekdayCalc({
rangeStart: '1 Apr 2015',
rangeEnd: '31 Mar 2016',
weekdays: [1,2,3,4,5], //weekdays Mon to Fri
exclusions: ['6 Apr 2015','7 Apr 2015'] //public holidays
}) //returns 260 (260 workdays excluding two public holidays)
If you want a pure JavaScript version (not relying on Moment.js) try this...
function addWeekdays(date, days) {
date.setDate(date.getDate());
var counter = 0;
if(days > 0 ){
while (counter < days) {
date.setDate(date.getDate() + 1 ); // Add a day to get the date tomorrow
var check = date.getDay(); // turns the date into a number (0 to 6)
if (check == 0 || check == 6) {
// Do nothing it's the weekend (0=Sun & 6=Sat)
}
else{
counter++; // It's a weekday so increase the counter
}
}
}
return date;
}
You call it like this...
var date = addWeekdays(new Date(), 3);
This function checks each next day to see if it falls on a Saturday (day 6) or Sunday (day 0). If true, the counter is not increased yet the date is increased.
This script is fine for small date increments like a month or less.
I would suggest adding a function to the moment prototype.
Something like this maybe? (untested)
nextWeekday : function () {
var day = this.clone(this);
day = day.add('days', 1);
while(day.weekday() == 0 || day.weekday() == 6){
day = day.add("days", 1);
}
return day;
},
nthWeekday : function (n) {
var day = this.clone(this);
for (var i=0;i<n;i++) {
day = day.nextWeekday();
}
return day;
},
And when you're done and written some tests, send in a pull request for bonus points.
d1 and d2 are moment dates passed as an argument to calculateBusinessDays
calculateBusinessDays(d1, d2) {
const days = d2.diff(d1, "days") + 1;
let newDay: any = d1.toDate(),
workingDays: number = 0,
sundays: number = 0,
saturdays: number = 0;
for (let i = 0; i < days; i++) {
const day = newDay.getDay();
newDay = d1.add(1, "days").toDate();
const isWeekend = ((day % 6) === 0);
if (!isWeekend) {
workingDays++;
}
else {
if (day === 6) saturdays++;
if (day === 0) sundays++;
}
}
console.log("Total Days:", days, "workingDays", workingDays, "saturdays", saturdays, "sundays", sundays);
return workingDays;
}
If you want a version of #acorio's code sample which is performant (using #Isantos's optimisation) and can deal with negative numbers use this:
moment.fn.addWorkdays = function (days) {
// Getting negative / positive increment
var increment = days / Math.abs(days);
// Looping weeks for each full 5 workdays
var date = this.clone().add(Math.floor(Math.abs(days) / 5) * 7 * increment, 'days');
// Account for starting on Saturdays and Sundays
if(date.isoWeekday() === 6) { date.add(-increment, 'days'); }
else if(date.isoWeekday() === 7) { date.add(-2 * increment, 'days'); }
// Adding / removing remaining days in a short loop, jumping over weekends
var remaining = days % 5;
while(remaining != 0) {
date.add(increment, 'days');
if(date.isoWeekday() !== 6 && date.isoWeekday() !== 7)
remaining -= increment;
}
return date;
};
See Fiddle here: http://jsfiddle.net/dain/5xrr79h0/
Edit: now fixed issue adding 5 days to a day initially on a weekend
I know this question was posted long ago, but in case somebody bump on this, here is optimized solution using moment.js:
function getBusinessDays(startDate, endDate){
var startDateMoment = moment(startDate);
var endDateMoment = moment(endDate)
var days = Math.round(startDateMoment.diff(endDateMoment, 'days') - startDateMoment .diff(endDateMoment, 'days') / 7 * 2);
if (endDateMoment.day() === 6) {
days--;
}
if (startDateMoment.day() === 7) {
days--;
}
return days;
}
const calcBusinessDays = (d1, d2) => {
// Calc all days used including last day ( the +1 )
const days = d2.diff(d1, 'days') + 1;
console.log('Days:', days);
// how many full weekends occured in this time span
const weekends = Math.floor( days / 7 );
console.log('Full Weekends:', weekends);
// Subtract all the weekend days
let businessDays = days - ( weekends * 2);
// Special case for weeks less than 7
if( weekends === 0 ){
const cur = d1.clone();
for( let i =0; i < days; i++ ){
if( cur.day() === 0 || cur.day() === 6 ){
businessDays--;
}
cur.add(1, 'days')
}
} else {
// If the last day is a saturday we need to account for it
if (d2.day() === 6 ) {
console.log('Extra weekend day (Saturday)');
businessDays--;
}
// If the first day is a sunday we need to account for it
if (d1.day() === 0) {
console.log('Extra weekend day (Sunday)');
businessDays--;
}
}
console.log('Business days:', businessDays);
return businessDays;
}
This can be done without looping between all dates in between.
// get nb of weekend days
var startDateMonday = startDate.clone().startOf('isoWeek');
var endDateMonday = endDate.clone().startOf('isoWeek');
var nbWeekEndDays = 2 * endDateMonday.diff(startDateMonday, 'days') / 7;
var isoDayStart = startDate.isoWeekday();
if (isoDayStart > 5) // starts during the weekend
{
nbWeekEndDays -= (8 - isoDayStart);
}
var isoDayEnd = endDate.isoWeekday();
if (isoDayEnd > 5) // ends during the weekend
{
nbWeekEndDays += (8 - isoDayEnd);
}
// if we want to also exlcude holidays
var startOfStartDate = startDate.clone().startOf('day');
var nbHolidays = holidays.filter(h => {
return h.isSameOrAfter(startOfStartDate) && h.isSameOrBefore(endDate);
}).length;
var duration = moment.duration(endDate.diff(startDate));
duration = duration.subtract({ days: nbWeekEndDays + nbHolidays });
var nbWorkingDays = Math.floor(duration.asDays()); // get only nb of complete days
I am iterating from start date to end date and only counting days which are weekdays.
const calculateBusinessDays = (start_date, end_date) => {
const d1 = start_date.clone();
let num_days = 0;
while(end_date.diff(d1.add(1, 'days')) > 0) {
if ([0, 6].includes(d1.day())) {
// Don't count the days
} else {
num_days++;
}
}
return num_days;
}

JavaScript Date.getWeek()? [duplicate]

This question already has answers here:
Get week of year in JavaScript like in PHP
(23 answers)
Closed 5 years ago.
I'm looking for a tested solid solution for getting current week of the year for specified date. All I can find are the ones that doesn't take in account leap years or just plain wrong. Does anyone have this type of stuff?
Or even better a function that says how many weeks does month occupy. It is usually 5, but can be 4 (feb) or 6 (1st is sunday and month has 30-31 days in it)
=================
UPDATE:
Still not sure about getting week #, but since I figured out it won't solve my problem with calculating how many weeks month occupy, I abandoned it.
Here's a function to find out how many weeks exactly month occupy on the calendar:
getWeeksNum: function(year, month) {
var daysNum = 32 - new Date(year, month, 32).getDate(),
fDayO = new Date(year, month, 1).getDay(),
fDay = fDayO ? (fDayO - 1) : 6,
weeksNum = Math.ceil((daysNum + fDay) / 7);
return weeksNum;
}
/**
* Returns the week number for this date. dowOffset is the day of week the week
* "starts" on for your locale - it can be from 0 to 6. If dowOffset is 1 (Monday),
* the week returned is the ISO 8601 week number.
* #param int dowOffset
* #return int
*/
Date.prototype.getWeek = function (dowOffset) {
/*getWeek() was developed by Nick Baicoianu at MeanFreePath: http://www.meanfreepath.com */
dowOffset = typeof(dowOffset) == 'number' ? dowOffset : 0; //default dowOffset to zero
var newYear = new Date(this.getFullYear(),0,1);
var day = newYear.getDay() - dowOffset; //the day of week the year begins on
day = (day >= 0 ? day : day + 7);
var daynum = Math.floor((this.getTime() - newYear.getTime() -
(this.getTimezoneOffset()-newYear.getTimezoneOffset())*60000)/86400000) + 1;
var weeknum;
//if the year starts before the middle of a week
if(day < 4) {
weeknum = Math.floor((daynum+day-1)/7) + 1;
if(weeknum > 52) {
nYear = new Date(this.getFullYear() + 1,0,1);
nday = nYear.getDay() - dowOffset;
nday = nday >= 0 ? nday : nday + 7;
/*if the next year starts before the middle of
the week, it is week #1 of that year*/
weeknum = nday < 4 ? 1 : 53;
}
}
else {
weeknum = Math.floor((daynum+day-1)/7);
}
return weeknum;
};
Usage:
var mydate = new Date(2011,2,3); // month number starts from 0
// or like this
var mydate = new Date('March 3, 2011');
alert(mydate.getWeek());
Source
For those looking for a more simple approach;
Date.prototype.getWeek = function() {
var onejan = new Date(this.getFullYear(),0,1);
var today = new Date(this.getFullYear(),this.getMonth(),this.getDate());
var dayOfYear = ((today - onejan + 86400000)/86400000);
return Math.ceil(dayOfYear/7)
};
Use with:
var today = new Date();
var currentWeekNumber = today.getWeek();
console.log(currentWeekNumber);
Consider using my implementation of "Date.prototype.getWeek", think is more accurate than the others i have seen here :)
Date.prototype.getWeek = function(){
// We have to compare against the first monday of the year not the 01/01
// 60*60*24*1000 = 86400000
// 'onejan_next_monday_time' reffers to the miliseconds of the next monday after 01/01
var day_miliseconds = 86400000,
onejan = new Date(this.getFullYear(),0,1,0,0,0),
onejan_day = (onejan.getDay()==0) ? 7 : onejan.getDay(),
days_for_next_monday = (8-onejan_day),
onejan_next_monday_time = onejan.getTime() + (days_for_next_monday * day_miliseconds),
// If one jan is not a monday, get the first monday of the year
first_monday_year_time = (onejan_day>1) ? onejan_next_monday_time : onejan.getTime(),
this_date = new Date(this.getFullYear(), this.getMonth(),this.getDate(),0,0,0),// This at 00:00:00
this_time = this_date.getTime(),
days_from_first_monday = Math.round(((this_time - first_monday_year_time) / day_miliseconds));
var first_monday_year = new Date(first_monday_year_time);
// We add 1 to "days_from_first_monday" because if "days_from_first_monday" is *7,
// then 7/7 = 1, and as we are 7 days from first monday,
// we should be in week number 2 instead of week number 1 (7/7=1)
// We consider week number as 52 when "days_from_first_monday" is lower than 0,
// that means the actual week started before the first monday so that means we are on the firsts
// days of the year (ex: we are on Friday 01/01, then "days_from_first_monday"=-3,
// so friday 01/01 is part of week number 52 from past year)
// "days_from_first_monday<=364" because (364+1)/7 == 52, if we are on day 365, then (365+1)/7 >= 52 (Math.ceil(366/7)=53) and thats wrong
return (days_from_first_monday>=0 && days_from_first_monday<364) ? Math.ceil((days_from_first_monday+1)/7) : 52;
}
You can check my public repo here https://bitbucket.org/agustinhaller/date.getweek (Tests included)
Get week number
Date.prototype.getWeek = function() {
var dt = new Date(this.getFullYear(),0,1);
return Math.ceil((((this - dt) / 86400000) + dt.getDay()+1)/7);
};
var myDate = new Date(2013, 3, 25); // 2013, 25 April
console.log(myDate.getWeek());
I know this is an old question, but maybe it helps:
http://weeknumber.net/how-to/javascript
// This script is released to the public domain and may be used, modified and
// distributed without restrictions. Attribution not necessary but appreciated.
// Source: https://weeknumber.net/how-to/javascript
// Returns the ISO week of the date.
Date.prototype.getWeek = function() {
var date = new Date(this.getTime());
date.setHours(0, 0, 0, 0);
// Thursday in current week decides the year.
date.setDate(date.getDate() + 3 - (date.getDay() + 6) % 7);
// January 4 is always in week 1.
var week1 = new Date(date.getFullYear(), 0, 4);
// Adjust to Thursday in week 1 and count number of weeks from date to week1.
return 1 + Math.round(((date.getTime() - week1.getTime()) / 86400000
- 3 + (week1.getDay() + 6) % 7) / 7);
}
// Returns the four-digit year corresponding to the ISO week of the date.
Date.prototype.getWeekYear = function() {
var date = new Date(this.getTime());
date.setDate(date.getDate() + 3 - (date.getDay() + 6) % 7);
return date.getFullYear();
}
/*get the week number by following the norms of ISO 8601*/
function getWeek(dt){
var calc=function(o){
if(o.dtmin.getDay()!=1){
if(o.dtmin.getDay()<=4 && o.dtmin.getDay()!=0)o.w+=1;
o.dtmin.setDate((o.dtmin.getDay()==0)? 2 : 1+(7-o.dtmin.getDay())+1);
}
o.w+=Math.ceil((((o.dtmax.getTime()-o.dtmin.getTime())/(24*60*60*1000))+1)/7);
},getNbDaysInAMonth=function(year,month){
var nbdays=31;
for(var i=0;i<=3;i++){
nbdays=nbdays-i;
if((dtInst=new Date(year,month-1,nbdays)) && dtInst.getDate()==nbdays && (dtInst.getMonth()+1)==month && dtInst.getFullYear()==year)
break;
}
return nbdays;
};
if(dt.getMonth()+1==1 && dt.getDate()>=1 && dt.getDate()<=3 && (dt.getDay()>=5 || dt.getDay()==0)){
var pyData={"dtmin":new Date(dt.getFullYear()-1,0,1,0,0,0,0),"dtmax":new Date(dt.getFullYear()-1,11,getNbDaysInAMonth(dt.getFullYear()-1,12),0,0,0,0),"w":0};
calc(pyData);
return pyData.w;
}else{
var ayData={"dtmin":new Date(dt.getFullYear(),0,1,0,0,0,0),"dtmax":new Date(dt.getFullYear(),dt.getMonth(),dt.getDate(),0,0,0,0),"w":0},
nd12m=getNbDaysInAMonth(dt.getFullYear(),12);
if(dt.getMonth()==12 && dt.getDay()!=0 && dt.getDay()<=3 && nd12m-dt.getDate()<=3-dt.getDay())ayData.w=1;else calc(ayData);
return ayData.w;
}
}
alert(getWeek(new Date(2017,01-1,01)));

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