Simple code to calculate age based on given date - javascript

If user enters dob as 10/19/1980, user's age is calculated based on 'effective date' instead of current date. There is a rule to calculate this 'effective date'.
// The rule is that if:
// current date is Feb 25 2021 : then 'effective date' is Apr-1-2021
// current date is Feb 3 2021, then 'effective date' is Mar 1 2021
const [effectiveDate, setEffectiveDate] = useState(new Date());
function calculateAge(userSelectedYear, dob) {
// dob is a string eg. 1980-10-19
const today = new Date();
const cutOffDate = new Date(today).getFullYear();
const selectedYear = userSelectedYear;
const defaultStartDate = new Date('2020-11-15');
const newDob = new Date(dob);
if (today.getFullYear() === selectedYear && cutOffDate > today) {
if (today.getDate() <= 15) {
// Current Date is on or before 15 of a month
setEffectiveDate(new Date(selectedYear, today.getMonth() + 1, 1));
} else {
// Current date is after 15th of the month
setEffectiveDate(new Date(selectedYear, today.getMonth() + 2, 1));
}
} else if (today.getFullYear() === selectedYear && cutOffDate <= today) {
setEffectiveDate(new Date(selectedYear, 11, 31));
} else {
setEffectiveDate(new Date(selectedYear, defaultStartDate.getMonth(), 1));
}
const age = effectiveDate.getFullYear() - newDob.getFullYear();
return age;
}
Is there a better way to right this code?

Using Moment.js:
var stringexample = "1980-10-19";
var x = moment(stringexample, "YYYY-MM-DD").fromNow(true);
document.getElementsByTagName("body")[0].innerText = x;
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.29.1/moment.min.js"></script>
If not using current time, you can calculate the difference between two dates using .diff().

Related

Find first monday date of month

I have a date (usually the first day of a month but not necessary, it could be any date) and I want a new date corresponding to the first Monday of that month.
example:
findFirstMonday('1 jul 2021') -> 7 jul 2021
findFirstMonday('1 aug 2021') -> 2 aug 2021
findFirstMonday('13 aug 2021') -> 2 aug 2021
Here is my code that doesn't work:
const selectedDate = new Date();
const daysInSelectedDate = daysInMonth(selectedDate);
const lastDayPreviousMonth = addDays(selectedDate, daysInSelectedDate - selectedDate.getDate() + 1);
const firstDayPreviousMonth = removeDays(
lastDayPreviousMonth,
daysInMonth(lastDayPreviousMonth),
);
console.log('firstDayPreviousMonth: ', firstDayPreviousMonth);
let firstMonday = firstDayPreviousMonth;
while (firstDayPreviousMonth.getDay() !== 1) {
console.log('firstMonday: ', firstMonday, firstMonday.getDay());
firstMonday.setDate(firstMonday.getDate() + 1);
}
console.log('firstMonday: ', firstMonday, firstMonday.getDay());
function addDays(date, days) {
const result = new Date(date)
result.setDate(result.getDate() + days)
return result
}
function removeDays(date, days) {
const result = new Date(date)
result.setDate(result.getDate() - days)
return result
}
function daysInMonth(date) {
return new Date(date.getFullYear(), date.getMonth(), 0).getDate()
}
What am I wrong?
Thanks a lot
I came up with the following code. Some explanations about the general idea:
For a given date get the first date in the month of the given date. This is quite easy by generating a new Date object with day = 1 and the year and month of the given date.
Get the weekday of the first date.
Depending on the weekday of the first date, you must calculate which day number the first Monday has. This number is calculated by ((8 - firstWeekdayInMonth) % 7). You can easily verify yourself, that this always yields a Monday. The modulo is important for Sundays and Mondays, where you would otherwise add 8 and 7 respectively, which would not yield the first Monday anymore.
console.log(findFirstMonday('1 jul 21'))
console.log(findFirstMonday('1 aug 21'))
console.log(findFirstMonday('13 aug 21'))
function findFirstMonday(dateString) {
let targetDate = new Date(dateString);
let targetMonth = targetDate.getMonth();
let targetYear = targetDate.getFullYear();
let firstDateInMonth = new Date(targetYear, targetMonth, 1);
let firstWeekdayInMonth = firstDateInMonth.getDay();
let firstMondayDate = 1 + ((8 - firstWeekdayInMonth) % 7);
return new Date(targetYear, targetMonth, firstMondayDate).toLocaleDateString();
}
Edit:
console.log(findFirstMondayMonth('1 jul 2021').toLocaleDateString())
console.log(findFirstMondayMonth('1 aug 2021').toLocaleDateString())
console.log(findFirstMondayMonth('2 aug 2021').toLocaleDateString())
console.log(findFirstMondayMonth('13 aug 2021').toLocaleDateString())
function findFirstMonday(dateString) {
let date = new Date(dateString)
let diffDay = date.getDay() - 1
if (diffDay == -1) {
diffDay = 6
}
let mondayDate = new Date(dateString);
mondayDate.setHours(mondayDate.getHours() - diffDay*24)
return mondayDate
}
function findFirstMondayMonth(dateString) {
let date = new Date(dateString)
if (date.getMonth() == findFirstMonday(date).getMonth()) {
let dateOneWeekBefore = new Date(dateString)
dateOneWeekBefore.setHours(dateOneWeekBefore.getHours() - 24 * 7)
if (date.getMonth() == dateOneWeekBefore.getMonth()) {
return findFirstMondayMonth(dateOneWeekBefore)
} else {
return findFirstMonday(date)
}
} else {
let dateOneWeekAfter = new Date(dateString)
dateOneWeekAfter.setHours(dateOneWeekAfter.getHours() + 24 * 7)
return findFirstMonday(dateOneWeekAfter)
}
}
Sorry for the last answer, I think it was the first monday of week and I don't see Sunday.getMonth() == -1

How to check if date is today or yetsterday or return date? [duplicate]

This question already has answers here:
Compare two dates with JavaScript
(43 answers)
Closed 2 years ago.
How can i check if input date is Today, Yesterday or just return the date if it's noone of them?
I was trying to do the following:
const checkDate = (someDate) => {
const today = new Date();
let date = new Date(someDate);
today.setHours(0);
today.setMinutes(0);
today.setSeconds(0);
return date.getTime() === today.getTime() ? "Oggi" : date.getTime() === today.setDay(-1) ? "Ieri" : "Il" + date;
}
console.log(checkDate("December 17, 1995 03:24:00"));
Where "Oggi" is Today and "Ieri" is Yesterday..
The easiest and most probably the right way is to use some library. Try day.js - small, but features rich (similar to Moment).
To install:
npm install dayjs
Or CDN:
<script src="https://unpkg.com/dayjs#1.8.21/dayjs.min.js"></script>
And you are ready to use all the set of features:
const someDate = new Date(); // plain old JS date
const now = dayjs(); // same (current date) but with day.js
// of course you can do: dayjs(someDate)
// yesterday: you check if someDate is current date - 1 day
const isYesterday = dayjs(someDate).isSame(dayjs().subtract(1, 'day'))
// today: just check if some date is equal to current date
const isToday = dayjs(someDate).isSame(dayjs()); // dayjs() return current date
// want to get back to plain old JS date
conat plainOldJsDate = dayjs('2019-01-25').toDate();
You can find more awesome features like parsing, manipulating, formatting, etc. in official docs.
isToday:
const isToday = (date) => {
const today = new Date()
return date.getDate() === today.getDate() &&
date.getMonth() === today.getMonth() &&
date.getFullYear() === today.getFullYear();
};
isYesterday:
const isYesterday = (date) => {
var yesterday= new Date();
yesterday; //# => today
date.setDate(date.getDate() - 1);
yesterday; //# => yesterday
return date.getDate() === yesterday.getDate() &&
date.getMonth() === yesterday.getMonth() &&
date.getFullYear() === yesterday.getFullYear();
}
The issue was that i missed to set mills and setDay was invalid, solved by using setDate(getDate() - 1) and by setting mills to 0
Here is the final solution
const checkDate = (someDate) => {
let today = new Date();
let date = new Date(someDate);
date = resetHours(date);
today = resetHours(today);
return date.getTime() === today.getTime() ? "Oggi" : date.getTime() === today.setDate(today.getDate() - 1) ? "Ieri" : "Il" + date;
}
const resetHours = (date) => {
date.setHours(0);
date.setMinutes(0);
date.setSeconds(0);
date.setMilliseconds(0);
return date;
}
You need to get the current date with a Date() object, then compare.
The function receives strings in the form of mm/dd/yyyy.
function checkDate(date) {
// get today
var today = new Date();
var dd = String(today.getDate()).padStart(2, '0');
var mm = String(today.getMonth() + 1).padStart(2, '0');
var yyyy = today.getFullYear();
// parse into strings
today = mm + '/' + dd + '/' + yyyy;
yesterday = mm + '/' + (dd-1) + '/' + yyyy;
if (today == date) {
return 'today';
}
if (today == yesterday) {
return 'yesterday';
}
else {
return date;
}
}
var date = '01/04/2021';
console.log(checkDate(date));
Compare .toDateString to check if a Date() is the same day:
const checkDate = (someDate) => {
// Create 'today' Date object
const today = new Date();
// Create 'someDate' Date object
const date = new Date(someDate);
// is Today
if (date.toDateString() === today.toDateString()) {
return 'today';
}
// Alter date to yesterday
today.setDate(today.getDate() - 1);
// is Yesterday
if (date.toDateString() === today.toDateString()) {
return 'yesterday';
}
// Fallback
return 'fallback'
}
console.log(checkDate('1/4/2021')); // today
console.log(checkDate('1/3/2021')); // yesterday
console.log(checkDate('1/9/2021')); // fallback
const isSameDay = (a, b) => {
return a.getFullYear() === b.getFullYear() &&
a.getMonth() === b.getMonth() &&
a.getDate()=== b.getDate();
}
const checkDate = (date) => {
const today = new Date();
const yesterday = new Date(Date.now() - 86400000); // 24 * 60 * 60 * 1000
if (isSameDay(today, date)) {
return "Today";
} else if (isSameDay(yesterday, date)) {
return "Yesterday";
} else {
return date.toDateString();
}
}
console.log(checkDate(new Date())); // "Today"
console.log(checkDate(new Date(Date.now() - 86400000))); // "Yesterday"
console.log(checkDate(new Date(Date.now() - 86400000 * 3))); // "Fri Jan 01 2021"
Date documentation in MDN

How to get a specify date in every month in Javascript?

I need to find this month, previous month and the next month of a specific date.
For example, date was set to 31 of every month, what I expect to get the date is
2018-02-28, 2018-03-31 and 2018-04-30. For those dates which has no 31, than it becomes the day before.
And finally generate 2 period, 2018-02-28 to 2018-03-29, 2018-03-30 to 2018-04-31.
I don't know how to handle feb and the month which less than 31.
var d = new Date();
var tyear = d.getFullYear(); //2018
var tmonth = d.getMonth(); //2
new Date(2018, tmonth-1, 31);//output 2018-03-02 not what I wanted
A simple algorithm is to add months to the original date, and if the new date is wrong, set it to the last day of the previous month. Keeping the original date values unmodified helps, e.g.
/* #param {Date} start - date to start
** #param {number} count - number of months to generate dates for
** #returns {Array} monthly Dates from start for count months
*/
function getMonthlyDates(start, count) {
var result = [];
var temp;
var year = start.getFullYear();
var month = start.getMonth();
var startDay = start.getDate();
for (var i=0; i<count; i++) {
temp = new Date(year, month + i, startDay);
if (temp.getDate() != startDay) temp.setDate(0);
result.push(temp);
}
return result;
}
// Start on 31 Jan in leap year
getMonthlyDates(new Date(2016,0,31), 4).forEach(d => console.log(d.toString()));
// Start on 31 Jan not in leap year
getMonthlyDates(new Date(2018,0,31), 4).forEach(d => console.log(d.toString()));
// Start on 30 Jan
getMonthlyDates(new Date(2018,0,30), 4).forEach(d => console.log(d.toString()));
// Start on 5 Jan
getMonthlyDates(new Date(2018,0,5), 4).forEach(d => console.log(d.toString()));
I think you're going to need an array with 12 numbers in it. Each number is the amount of days in each month and the numbers in the array go in order (first number is 31 because January has 31 days, second is 28 or 29 for Feb), etc. Then you'll get the month number from your input date and look in the array at the number corresponding to the month number +/- 1.
You'll then need to construct a date for the previous month and the next month based on the number of days in the current month.
See comments inline:
let daysInMonths = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
document.getElementById("date").addEventListener("input", function(){
console.clear();
// Create new Date based on value in date picker
var selectedDate = new Date(this.value + 'T00:00');
var year = selectedDate.getYear();
// Determine if it is a leap year (Feb has 29 days) and update array if so.
if (((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0)) {
daysInMonths[1] = 29;
}
var selectedDateMonth = selectedDate.getMonth();
// Get previous month number (if current month is January, get December)
let prevMonth = selectedDateMonth > 0 ? selectedDateMonth - 1 : 11;
let prevMonthDate = null;
// If selected date is last day of month...
if(selectedDate.getDate() === daysInMonths[selectedDateMonth]){
// Create new date that takes the selected date and subtracts the correct amount of
// days from it based on a lookup in the array.
var newDate1 = new Date(selectedDate.getTime());
prevMonthDate =
new Date(newDate1.setDate(selectedDate.getDate() - daysInMonths[selectedDateMonth]));
} else {
// Create a new date that is last month and one day earlier
var newDate2 = new Date(selectedDate.getTime());
prevMonthDate =
new Date(new Date(newDate2.setDate(selectedDate.getDate() - 1))
.setMonth(selectedDate.getMonth() - 1));
}
// Get next month (if current month is December, get January
let nextMonth = selectedDateMonth < 11 ? selectedDateMonth + 1 : 0;
let nextMonthDate = null;
// Same idea for next month, but add instead of subtract.
// If selected date is last day of month...
if(selectedDate.getDate() === daysInMonths[selectedDateMonth]){
var newDate3 = new Date(selectedDate.getTime());
nextMonthDate =
new Date(newDate3.setDate(selectedDate.getDate() + daysInMonths[selectedDateMonth + 1]));
} else {
var newDate4 = new Date(selectedDate.getTime());
nextMonthDate = new Date(new Date(newDate4.setDate(selectedDate.getDate() + 1)).setMonth(selectedDate.getMonth() + 1));
}
console.log("Last month date: " + prevMonthDate.toLocaleDateString());
console.log("Next month date: " + nextMonthDate.toLocaleDateString());
});
<p>Pick a date: <input type="date" id="date"></p>
Use this approach:
Javascript Date Object – Adding and Subtracting Months
From the Author
There is a slight problem with the Javascript Date() Object when trying to advance to the next month or go back to the previous month.
For example, if your date is set to October 31, 2018 and you add one month, you'd probably expect the new date to be November 30, 2018 because November 31st doesn't exist. This, however, isn't the case.
Javascript automatically advances your Date object to December 1st. This functionality is very useful in most situations(i.e. adding days to a date, determining the number of days in a month or if it's a leap year), but not for adding/subtracting months. I've put together some functions below that extend the Date() object: nextMonth() and prevMonth().
function prevMonth() {
var thisMonth = this.getMonth();
this.setMonth(thisMonth - 1);
if (this.getMonth() != thisMonth - 1 && (this.getMonth() != 11 || (thisMonth == 11 && this.getDate() == 1)))
this.setDate(0);
}
function nextMonth() {
var thisMonth = this.getMonth();
this.setMonth(thisMonth + 1);
if (this.getMonth() != thisMonth + 1 && this.getMonth() != 0)
this.setDate(0);
}
Date.prototype.nextMonth = nextMonth;
Date.prototype.prevMonth = prevMonth;
var today = new Date(2018, 2, 31); //<----- March 31st, 2018
var prevMonth = new Date(today.getTime());
prevMonth.prevMonth();
console.log("Previous month:", prevMonth);
console.log("This month:", today)
var nextMonth = new Date(today.getTime());
nextMonth.nextMonth();
console.log("Next month:", nextMonth);
.as-console-wrapper { max-height: 100% !important; top: 0; }
Dates and time zones are a real pain in JS, so challenge accepted.
I broke it down in two steps:
- Count the days of prev and next month
- Compare with selected day and pick the lowest number
Testcases included
function createUTCDate(year, month, day) {
return new Date(Date.UTC(year, month, day));
}
function splitDate(date) {
return {
year: date.getUTCFullYear(),
month: date.getUTCMonth(),
day: date.getUTCDate()
};
}
function numberOfDaysInMonth(year, month) {
return new Date(year, month + 1, 0).getDate();
}
function dateNextMonth(dateObj) {
const daysNextMonth = numberOfDaysInMonth(dateObj.year, dateObj.month + 1);
const day = Math.min(daysNextMonth, dateObj.day);
return createUTCDate(dateObj.year, dateObj.month + 1, day);
}
function datePreviousMonth(dateObj) {
const daysPrevMonth = numberOfDaysInMonth(dateObj.year, dateObj.month - 1);
const day = Math.min(daysPrevMonth, dateObj.day);
return createUTCDate(dateObj.year, dateObj.month - 1, day);
}
const log = console.log;
function print(dateString) {
const date = new Date(dateString);
const dateObj = splitDate(date);
log("Previous: ", datePreviousMonth(dateObj).toISOString());
log("Selected: ", date.toISOString());
log("Next: ", dateNextMonth(dateObj).toISOString());
log("--------------");
}
const testCases = [
"2018-03-01 UTC",
"2018-03-31 UTC",
"2018-01-01 UTC",
"2018-12-31 UTC"
];
testCases.forEach(print);
Please note that the hack with new Date(xxx + " UTC") is not according to spec and is just there for testing purposes. Results may vary per browser.
You should choose an input format and construct your dates accordingly.
I handle it in a foolish way by concatenating string
let daysInMonths = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
let months = ["01", "02", "03", "04", "05", "06", "07", "08", "09", "10", "11", "12"];
var target = nexttarget = lasttarget = "29"; //target day
if (((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0)) {
daysInMonths[1] = 29;
}
function findLastDay(target, month){
if(target > daysInMonths[month]){
target = daysInMonths[month];
}
return target;
}
then
var d = new Date();
var year = d.getFullYear();
var month = d.getMonth();
target = findLastDay(target, month);
var this_month = year+"-"+months[month]+"-"+target;
console.log(this_month);//2018-03-29
// next month
if(month == 11){
nextmonth = 0;
nextyear = year + 1;
}else{
nextmonth = month+1;
nextyear = year;
}
nexttarget = findLastDay(nexttarget, nextmonth);
var next_month = nextyear+"-"+months[nextmonth]+"-"+nexttarget;
console.log(next_month);//2018-04-29
//last month
if(month == 0){
lastmonth = 11;
lastyear = year - 1;
}else{
lastmonth = month - 1;
lastyear = year;
}
lasttarget = findLastDay(lasttarget, lastmonth);
var last_month = lastyear+"-"+months[lastmonth]+"-"+lasttarget;
console.log(last_month);//2018-02-28
Date handling is tricky at the best of times. Don't do this yourself. Use Moment.js.
var target = 31;
var today = moment().date(target).calendar();
// today == '03/31/2018'
var nextMonth = moment().date(target).add(1, 'month').calendar();
// nextMonth == '04/30/2018'
var lastMonth = moment().date(target).subtract(1, 'month').calendar()
// lastMonth == '02/28/2018'

MomentJS check if next day and get days apart

How can I check if it's the next day?
const startDate = moment(item.start_time);
const endDate = moment(item.end_time);
const dateDiff = startDate.diff(endDate, 'days', true)
const nextDay = dateDiff > 1
It works for dates like Aug 14th 2PM to Aug 14th 4PM however it doesn't work for dates like Aug 14th 4PM to Aug 14th 2PM.
How can I fix it?
If possible I would like to get the number of days apart they are.
const startDate = moment(item.start_time);
const endDate = moment(item.end_time);
const dateDiff = startDate.diff(endDate, 'days', true) mod 1
Use getDate & setDate methods to increase the current date object by exactly a day. Afterwards you need just compare the date year, month and date.
var isNextDay = function(next, current) {
var date = new Date(current);
date.setDate(date.getDate() + 1);
return (date.getFullYear() === next.getFullYear()) && (date.getMonth() === next.getMonth()) && (date.getDate() === next.getDate());
};
var currentDay = new Date('2016-05-31 16:00:00');
var nextDay = new Date('2016-06-01 14:00:00');
console.log('It is ' + (isNextDay(nextDay, currentDay) ? '' : 'not ') + 'the next day');
Check this code:
var currentDay =new moment('2016-05-31 16:00:00');
var nextDay = new moment('2016-06-01 14:00:00');
console.log('It is ' + (nextDay.isSame(currentDay.add(1, 'days'), 'd') === true ? '' : 'not ') + 'the next day');
jsfiddle

group by weeks,days and year javascript [duplicate]

I have today = new Date(); object. I need to get first and last day of the current week. I need both variants for Sunday and Monday as a start and end day of the week. I am little bit confuse now with a code. Can your help me?
var curr = new Date; // get current date
var first = curr.getDate() - curr.getDay(); // First day is the day of the month - the day of the week
var last = first + 6; // last day is the first day + 6
var firstday = new Date(curr.setDate(first)).toUTCString();
var lastday = new Date(curr.setDate(last)).toUTCString();
firstday
"Sun, 06 Mar 2011 12:25:40 GMT"
lastday
"Sat, 12 Mar 2011 12:25:40 GMT"
This works for firstday = sunday of this week and last day = saturday for this week. Extending it to run Monday to sunday is trivial.
Making it work with first and last days in different months is left as an exercise for the user
Be careful with the accepted answer, it does not set the time to 00:00:00 and 23:59:59, so you can have problems.
You can use a third party date library to deal with dates. For example:
var startOfWeek = moment().startOf('week').toDate();
var endOfWeek = moment().endOf('week').toDate();
EDIT: As of September 2020, using Moment is discouraged for new projects (blog post)
Another popular alternative is date-fns.
You can also use following lines of code to get first and last date of the week:
var curr = new Date;
var firstday = new Date(curr.setDate(curr.getDate() - curr.getDay()));
var lastday = new Date(curr.setDate(curr.getDate() - curr.getDay()+6));
Hope it will be useful..
The excellent (and immutable) date-fns library handles this most concisely:
const start = startOfWeek(date);
const end = endOfWeek(date);
Default start day of the week is Sunday (0), but it can be changed to Monday (1) like this:
const start = startOfWeek(date, {weekStartsOn: 1});
const end = endOfWeek(date, {weekStartsOn: 1});
Here's a quick way to get first and last day, for any start day.
knowing that:
1 day = 86,400,000 milliseconds.
JS dates values are in milliseconds
Recipe: figure out how many days you need to remove to get the your week's start day (multiply by 1 day's worth of milliseconds). All that is left after that is to add 6 days to get your end day.
var startDay = 1; //0=sunday, 1=monday etc.
var d = now.getDay(); //get the current day
var weekStart = new Date(now.valueOf() - (d<=0 ? 7-startDay:d-startDay)*86400000); //rewind to start day
var weekEnd = new Date(weekStart.valueOf() + 6*86400000); //add 6 days to get last day
Small change to #Chris Lang answer.
if you want Monday as the first day use this.
Date.prototype.GetFirstDayOfWeek = function() {
return (new Date(this.setDate(this.getDate() - this.getDay()+ (this.getDay() == 0 ? -6:1) )));
}
Date.prototype.GetLastDayOfWeek = function() {
return (new Date(this.setDate(this.getDate() - this.getDay() +7)));
}
var today = new Date();
alert(today.GetFirstDayOfWeek());
alert(today.GetLastDayOfWeek());
Thaks #Chris Lang
This works across year and month changes.
Date.prototype.GetFirstDayOfWeek = function() {
return (new Date(this.setDate(this.getDate() - this.getDay())));
}
Date.prototype.GetLastDayOfWeek = function() {
return (new Date(this.setDate(this.getDate() - this.getDay() +6)));
}
var today = new Date();
alert(today.GetFirstDayOfWeek());
alert(today.GetLastDayOfWeek());
You could do something like this
var today = new Date();
var startDay = 0;
var weekStart = new Date(today.getDate() - (7 + today.getDay() - startDay) % 7);
var weekEnd = new Date(today.getDate() + (7 - today.getDay() - startDay) % 7);
Where startDay is a number from 0 to 6 where 0 stands for Sunday (ie 1 = Monday, 2 = Tuesday, etc).
SetDate will sets the day of the month. Using setDate during start and end of the month,will result in wrong week
var curr = new Date("08-Jul-2014"); // get current date
var first = curr.getDate() - curr.getDay(); // First day is the day of the month - the day of the week
var last = first + 6; // last day is the first day + 6
var firstday = new Date(curr.setDate(first)); // 06-Jul-2014
var lastday = new Date(curr.setDate(last)); //12-Jul-2014
If u setting Date is 01-Jul-2014, it will show firstday as 29-Jun-2014 and lastday as 05-Jun-2014 instead of 05-Jul-2014
So overcome this issue i used
var curr = new Date();
day = curr.getDay();
firstday = new Date(curr.getTime() - 60*60*24* day*1000); //will return firstday (ie sunday) of the week
lastday = new Date(firstday.getTime() + 60 * 60 *24 * 6 * 1000); //adding (60*60*6*24*1000) means adding six days to the firstday which results in lastday (saturday) of the week
I recommend to use Moment.js for such cases. I had scenarios where I had to check current date time, this week, this month and this quarters date time. Above an answer helped me so I thought to share rest of the functions as well.
Simply to get current date time in specific format
case 'Today':
moment().format("DD/MM/YYYY h:mm A");
case 'This Week':
moment().endOf('isoweek').format("DD/MM/YYYY h:mm A");
Week starts from Sunday and ends on Saturday if we simply use 'week' as parameter for endOf function but to get Sunday as the end of the week we need to use 'isoweek'.
case 'This Month':
moment().endOf('month').format("DD/MM/YYYY h:mm A");
case 'This Quarter':
moment().endOf('quarter').format("DD/MM/YYYY h:mm A");
I chose this format as per my need. You can change the format according to your requirement.
//get start of week; QT
function _getStartOfWeek (date){
var iDayOfWeek = date.getDay();
var iDifference = date.getDate() - iDayOfWeek + (iDayOfWeek === 0 ? -6:1);
return new Date(date.setDate(iDifference));
},
function _getEndOfWeek(date){
return new Date(date.setDate(date.getDate() + (7 - date.getDay()) === 7 ? 0 : (7 - date.getDay()) ));
},
*current date == 30.06.2016 and monday is the first day in week.
It also works for different months and years.
Tested with qunit suite:
QUnit.module("Planung: Start of week");
QUnit.test("Should return start of week based on current date", function (assert) {
var startOfWeek = Planung._getStartOfWeek(new Date());
assert.ok( startOfWeek , "returned date: "+ startOfWeek);
});
QUnit.test("Should return start of week based on a sunday date", function (assert) {
var startOfWeek = Planung._getStartOfWeek(new Date("2016-07-03"));
assert.ok( startOfWeek , "returned date: "+ startOfWeek);
});
QUnit.test("Should return start of week based on a monday date", function (assert) {
var startOfWeek = Planung._getStartOfWeek(new Date("2016-06-27"));
assert.ok( startOfWeek , "returned date: "+ startOfWeek);
});
QUnit.module("Planung: End of week");
QUnit.test("Should return end of week based on current date", function (assert) {
var endOfWeek = Planung._getEndOfWeek(new Date());
assert.ok( endOfWeek , "returned date: "+ endOfWeek);
});
QUnit.test("Should return end of week based on sunday date with different month", function (assert) {
var endOfWeek = Planung._getEndOfWeek(new Date("2016-07-03"));
assert.ok( endOfWeek , "returned date: "+ endOfWeek);
});
QUnit.test("Should return end of week based on monday date with different month", function (assert) {
var endOfWeek = Planung._getEndOfWeek(new Date("2016-06-27"));
assert.ok( endOfWeek , "returned date: "+ endOfWeek);
});
QUnit.test("Should return end of week based on 01-06-2016 with different month", function (assert) {
var endOfWeek = Planung._getEndOfWeek(new Date("2016-06-01"));
assert.ok( endOfWeek , "returned date: "+ endOfWeek);
});
QUnit.test("Should return end of week based on 21-06-2016 with different month", function (assert) {
var endOfWeek = Planung._getEndOfWeek(new Date("2016-06-21"));
assert.ok( endOfWeek , "returned date: "+ endOfWeek);
});
QUnit.test("Should return end of week based on 28-12-2016 with different month and year", function (assert) {
var endOfWeek = Planung._getEndOfWeek(new Date("2016-12-28"));
assert.ok( endOfWeek , "returned date: "+ endOfWeek);
});
QUnit.test("Should return end of week based on 01-01-2016 with different month and year", function (assert) {
var endOfWeek = Planung._getEndOfWeek(new Date("2016-01-01"));
assert.ok( endOfWeek , "returned date: "+ endOfWeek);
});
var dt = new Date() //current date of week
var currentWeekDay = dt.getDay();
var lessDays = currentWeekDay == 0 ? 6 : currentWeekDay-1
var wkStart = new Date(new Date(dt).setDate(dt.getDate()- lessDays));
var wkEnd = new Date(new Date(wkStart).setDate(wkStart.getDate()+6));
This will be useful for any date scenario.
Just using pure javascript, you can use the function below to get first day and last day of a week with freely setting day for start of week.
var weekday = [];
weekday[0] = "Sunday";
weekday[1] = "Monday";
weekday[2] = "Tuesday";
weekday[3] = "Wednesday";
weekday[4] = "Thursday";
weekday[5] = "Friday";
weekday[6] = "Saturday";
function getFirstDayOfWeek(date, from) {
//Default start week from 'Sunday'. You can change it yourself.
from = from || 'Sunday';
var index = weekday.indexOf(from);
var start = index >= 0 ? index : 0;
var d = new Date(date);
var day = d.getDay();
var diff = d.getDate() - day + (start > day ? start - 7 : start);
d.setDate(diff);
return d;
};
Last day of week is just 6 days after first day of week
function getLastDayOfWeek(date, from) {
from = from || 'Sunday';
var index = weekday.indexOf(from);
var start = index >= 0 ? index : 0;
var d = new Date(date);
var day = d.getDay();
var diff = d.getDate() - day + (start > day ? start - 1 : 6 + start);
d.setDate(diff);
return d;
};
Test:
getFirstDayOfWeek('2017-10-16'); //--> Sun Oct 15 2017
getFirstDayOfWeek('2017-10-16', 'Monday'); //--> Mon Oct 16 2017
getFirstDayOfWeek('2017-10-16', 'Tuesday'); //--> Tue Oct 10 2017
The biggest issue when the given date's week is in-between two months. (Like 2022-07-01, it's the 5th day of the week.)
Using getDay function we check if the week is in-between months.
Note: getDay() function identifies week start day as sunday, so it'll return 0 for sunday.
var curr = new Date(); // get current date
var weekdaynum = curr.getDay();
if(weekdaynum == 0){ //to change sunday to the last day of the week
weekdaynum = 6;
} else{
weekdaynum = weekdaynum-1;
}
var firstweek = curr.getDate() - weekdaynum;
var lastweek = firstweek + 6; // last day is the first day + 6
if((curr.getDate()-weekdaynum) <= 0){
var firstweek_lasmonth_lastdate = new Date(currweek.getFullYear(),currweek.getMonth(), 0);
var firstweek_diff = firstweek_lasmonth_lastdate.getDate()-Math.abs(firstweek);
var firstweekday = new Date(currweek.getFullYear(),currweek.getMonth()-1,firstweek_lasmonth_lastdate.getDate()+firstweek_diff);
var lastweekday = new Date(currweek.getFullYear(),currweek.getMonth()-1,firstweek_lasmonth_lastdate.getDate()+firstweek_diff+7);
} else{
var firstweekday = new Date(curr.setDate(firstweek));
var lastweekday = new Date(curr.setDate(lastweek));
}
So this will return (given date is: 2022/07/01):
firstweekday = Mon Jun 27 2022 00:00:00
lastweekday = Sun Jul 03 2022 00:00:00
Hope this helps.
krtek's method has some wrong,I tested this
var startDay = 0;
var weekStart = new Date(today.getDate() - (7 + today.getDay() - startDay) % 7);
var weekEnd = new Date(today.getDate() + (6 - today.getDay() - startDay) % 7);
it works
Although the question is seeming as obsolete I have to point out a problem.
Question: What will happen at 1st January 2016?
I think most of the above solutions calculate start of week as 27.12.2016.
For this reason I think, the correct calculation should be like the below simply;
var d = new Date(),
dayInMs = 1000 * 60 * 60 * 24,
weekInMs = dayInMs * 7,
startOfToday = new Date(d.getFullYear(), d.getMonth(), d.getDate()).valueOf(),
todayElapsedTime = d.valueOf() - startOfToday,
dayDiff = d.getDay() * dayInMs,
dateDiff = dayDiff + todayElapsedTime,
// finally
startOfWeek = d.valueOf() - dateDiff,
endOfWeek = startOfWeek + weekInMs - 1;
JavaScript
function getWeekDays(curr, firstDay = 1 /* 0=Sun, 1=Mon, ... */) {
var cd = curr.getDate() - curr.getDay();
var from = new Date(curr.setDate(cd + firstDay));
var to = new Date(curr.setDate(cd + 6 + firstDay));
return {
from,
to,
};
};
TypeScript
export enum WEEK_DAYS {
Sunday = 0,
Monday = 1,
Tuesday = 2,
Wednesday = 3,
Thursday = 4,
Friday = 5,
Saturday = 6,
}
export const getWeekDays = (
curr: Date,
firstDay: WEEK_DAYS = WEEK_DAYS.Monday
): { from: Date; to: Date } => {
const cd = curr.getDate() - curr.getDay();
const from = new Date(curr.setDate(cd + firstDay));
const to = new Date(curr.setDate(cd + 6 + firstDay));
return {
from,
to,
};
};
function getMonday(d) {
d = new Date(d);
var day = d.getDay(),
diff = d.getDate() - day + (day == 0 ? -6:1); // adjust when day is sunday
return new Date(d.setDate(diff));
}
console.log( getMonday(new Date(new Date().getFullYear(), new Date().getMonth(), new Date().getDate())) ) // Mon Nov 08 2010
Pure vanilla JS. no third party libraries.
const now = new Date()
const startOfWeek = new Date(now.getFullYear(), now.getMonth(), now.getDate() - now.getDay())
const endOfWeek = new Date(now.getFullYear(), now.getMonth(), startOfWeek.getDate() + 7)
^ this returns Sunday 00am to Sunday 00am. Adjust the "7" to get what you want.
var currentDate = new Date();
var firstday = new Date(currentDate.setDate(currentDate.getDate() - currentDate.getDay())).toUTCString();
var lastday = new Date(currentDate.setDate(currentDate.getDate() - currentDate.getDay() + 6)).toUTCString();
console.log("firstday", firstday);
console.log("lastday", lastday);
Works with different months and years.
let wDate = new Date();
let dDay = wDate.getDay() > 0 ? wDate.getDay() : 7;
let first = wDate.getDate() - dDay + 1;
let firstDayWeek = new Date(wDate.setDate(first));
let lastDayWeek = new Date(wDate.setDate(firstDayWeek.getDate()+6));
console.log(firstDayWeek.toLocaleDateString());
console.log(lastDayWeek.toLocaleDateString());
Nice suggestion but you got a small problem in lastday.
You should change it to:
lastday = new Date(firstday.getTime() + 60 * 60 *24 * 6 * 1000);
The moment approach worked for me for all the cases ( although i have not test the boundaries like year end , leap years ). Only Correction in the above code is the parameter is "isoWeek" , if you want to start the week from Monday.
let startOfWeek = moment().startOf("isoWeek").toDate();
let endOfWeek = moment().endOf("isoWeek").toDate();
We have added jquery code that shows the current week of days from monday to sunday.
var d = new Date();
var week = [];
var _days = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'];
var _months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
for (let i = 1; i <= 7; i++) {
let first = d.getDate() - d.getDay() + i;
let dt = new Date(d.setDate(first));
var _day = _days[dt.getDay()];
var _month = _months[dt.getMonth()];
var _date = dt.getDate();
if(_date < 10 ){
_date = '0' +_date;
}
var _year = dt.getFullYear();
var fulldate = _day+' '+_month+' '+_date+' '+_year+' ';
week.push(fulldate);
}
console.log(week);
An old question with lots of answers, so another one won't be an issue. Some general functions to get the start and end of all sorts of time units.
For startOf and endOf week, the start day of the week defaults to Sunday (0) but any day can be passed (Monday - 1, Tuesday - 2, etc.). Only uses Gregorian calendar though.
The functions don't mutate the source date, so to see if a date is in the same week as some other date (week starting on Monday):
if (d >= startOf('week', d1, 1) && d <= endOf('week', d1, 1)) {
// d is in same week as d1
}
or in the current week starting on Sunday:
if (d >= startOf('week') && d <= endOf('week')) {
// d is in the current week
}
// Returns a new Date object set to start of given unit
// For start of week, accepts any day as start
function startOf(unit, date = new Date(), weekStartDay = 0) {
// Copy original so don't modify it
let d = new Date(date);
let e = new Date(d);
e.setHours(23,59,59,999);
// Define methods
let start = {
second: d => d.setMilliseconds(0),
minute: d => d.setSeconds(0,0),
hour : d => d.setMinutes(0,0,0),
day : d => d.setHours(0,0,0,0),
week : d => {
start.day(d);
d.setDate(d.getDate() - d.getDay() + weekStartDay);
if (d > e) d.setDate(d.getDate() - 7);
},
month : d => {
start.day(d);
d.setDate(1);
},
year : d => {
start.day(d);
d.setMonth(0, 1);
},
decade: d => {
start.year(d);
let year = d.getFullYear();
d.setFullYear(year - year % 10);
},
century: d => {
start.year(d);
let year = d.getFullYear();
d.setFullYear(year - year % 100);
},
millenium: d => {
start.year(d);
let year = d.getFullYear();
d.setFullYear(year - year % 1000);
}
}
start[unit](d);
return d;
}
// Returns a new Date object set to end of given unit
// For end of week, accepts any day as start day
// Requires startOf
function endOf(unit, date = new Date(), weekStartDay = 0) {
// Copy original so don't modify it
let d = new Date(date);
let e = new Date(date);
e.setHours(23,59,59,999);
// Define methods
let end = {
second: d => d.setMilliseconds(999),
minute: d => d.setSeconds(59,999),
hour : d => d.setMinutes(59,59,999),
day : d => d.setHours(23,59,59,999),
week : w => {
w = startOf('week', w, weekStartDay);
w.setDate(w.getDate() + 6);
end.day(w);
d = w;
},
month : d => {
d.setMonth(d.getMonth() + 1, 0);
end.day(d);
},
year : d => {
d.setMonth(11, 31);
end.day(d);
},
decade: d => {
end.year(d);
let y = d.getFullYear();
d.setFullYear(y - y % 10 + 9);
},
century: d => {
end.year(d);
let y = d.getFullYear();
d.setFullYear(y - y % 100 + 99);
},
millenium: d => {
end.year(d);
let y = d.getFullYear();
d.setFullYear(y - y % 1000 + 999);
}
}
end[unit](d);
return d;
}
// Examples
let d = new Date();
['second','minute','hour','day','week','month','year',
'decade','century','millenium'].forEach(unit => {
console.log(('Start of ' + unit).padEnd(18) + ': ' +
startOf(unit, d).toString());
console.log(('End of ' + unit).padEnd(18) + ': ' +
endOf(unit, d).toString());
});
var currentDate = new Date();
var firstday = new Date(currentDate.setDate(currentDate.getDate() - currentDate.getDay())).toUTCString();
var lastday = new Date(currentDate.setDate(currentDate.getDate() - currentDate.getDay() + 7)).toUTCString();
console.log(firstday, lastday)
I'm using the following code in but because of .toUTCString() i'm receiving the following error as show in image.
if i remove .toUTCString(). output which i receive is not as expected
Small change to #SHIVA's answer which is a changed #Chris Lang answer.
For monday first usage with fix when today is sunday.
Date.prototype.GetFirstDayOfWeek = function() {
return (new Date(this.setDate(this.getDate() - this.getDay()+ (this.getDay() == 0 ? -6:1) )));
}
Date.prototype.GetLastDayOfWeek = function() {
return new Date(this.setDate(this.getDate() - (this.getDay() == 0 ? 7 : this.getDay()) + 7));
}
var today = new Date();
alert(today.GetFirstDayOfWeek());
alert(today.GetLastDayOfWeek());
You can try the below one too
let weekBgnDt = new Date();
let weekEndDt = new Date();
let wBeginDateLng, wEndDateLng, diffDays,dateCols=[];
if (weekBgnDt.getDay() > 0) {
diffDays = 0 - weekBgnDt.getDay();
weekBgnDt.setDate(weekBgnDt.getDate() + diffDays)
}
weekEndDt = weekEndDt.setDate(weekBgnDt.getDate() + 6)
wBeginDate = new Intl.DateTimeFormat('en-GB', { day: 'numeric', year: 'numeric',
month: '2-digit' }).format(weekBgnDt);
wEndDate = new Intl.DateTimeFormat('en-GB', { day: 'numeric', year: 'numeric', month:
'2-digit' }).format(weekEndDt);
wBeginDateLng = new Intl.DateTimeFormat('en-GB', { day: 'numeric', year: 'numeric',
month: 'long' }).format(weekBgnDt);
wEndDateLng = new Intl.DateTimeFormat('en-GB', { day: 'numeric', year: 'numeric',
month: 'long' }).format(weekEndDt);
console.log(wBeginDate, "-", wBeginDateLng)
console.log(wEndDate, "-", wEndDateLng)
for(let i=weekBgnDt;i<=weekEndDt;){
dateCols.push(new Intl.DateTimeFormat('en-GB', { day: 'numeric', year: 'numeric',
month: '2-digit' }).format(i));
i=weekBgnDt.setDate(weekBgnDt.getDate()+1)
}
console.log({wBeginDate,wBeginDateLng,wEndDate,wEndDateLng,dateCols})
The result will be printed as
{ wBeginDate: "16/05/2021", wBeginDateLng: "16 May 2021", wEndDate: "22/05/2021", wEndDateLng: "22 May 2021", dateCols: Array ["16/05/2021", "17/05/2021", "18/05/2021", "19/05/2021", "20/05/2021", "21/05/2021", "22/05/2021"] }
The right way to get the first and last date of the current week with appropriate month & year is as below
const curr = new Date();
const first = curr.getDate() - curr.getDay() + 1; // Start from Monday
const firstDate = new Date(curr.setDate(first));
const lastDate = new Date(curr.setDate(firstDate.getDate() + 6));
console.log(firstDate.toLocaleDateString(), lastDate.toLocaleDateString());
You can use this function, it works with first and last day of the week in different months or years
const getFirstAndLastDayOfTheWeek = () => {
// The starting time is the same current
let a = new Date();
let b = new Date();
const weekDay = a.getDay();
if (weekDay === 0) {
a.setDate(a.getDate() - 6);
} else if (weekDay === 1) {
b.setDate(b.getDate() + 7 - b.getDay());
} else if (weekDay >= 1) {
a.setDate(a.getDate() - a.getDay() + 1);
b.setDate(b.getDate() + 7 - b.getDay());
}
return { firstWeekDate: a, lastWeekDate: b };
}
console.log(getFirstAndLastDayOfTheWeek());

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