I am trying to calculate number of weeks in a month using moment js. But I am getting wrong results for some months like May 2015 and August 2015.
I am using this code.
var start = moment().startOf('month').format('DD');
var end = moment().endOf('month').format('DD');
var weeks = (end-start+1)/7;
weeks = Math.ceil(weeks);
Is there any prebuilt method in moment JS for getting number of weeks.
I have created this gist that finds all the weeks in a given month and year. By calculated the length of calendar, you will know the number of weeks.
https://gist.github.com/guillaumepiot/095b5e02b4ca22680a50
# year and month are variables
year = 2015
month = 7 # August (0 indexed)
startDate = moment([year, month])
# Get the first and last day of the month
firstDay = moment(startDate).startOf('month')
endDay = moment(startDate).endOf('month')
# Create a range for the month we can iterate through
monthRange = moment.range(firstDay, endDay)
# Get all the weeks during the current month
weeks = []
monthRange.by('days', (moment)->
if moment.week() not in weeks
weeks.push(moment.week())
)
# Create a range for each week
calendar = []
for week in weeks
# Create a range for that week between 1st and 7th day
firstWeekDay = moment().week(week).day(1)
lastWeekDay = moment().week(week).day(7)
weekRange = moment.range(firstWeekDay, lastWeekDay)
# Add to the calendar
calendar.push(weekRange)
console.log calendar
function getWeekNums(momentObj) {
var clonedMoment = moment(momentObj), first, last;
// get week number for first day of month
first = clonedMoment.startOf('month').week();
// get week number for last day of month
last = clonedMoment.endOf('month').week();
// In case last week is in next year
if( first > last) {
last = first + last;
}
return last - first + 1;
}
Can be easily done using raw javascript:
function getNumWeeksForMonth(year,month){
date = new Date(year,month-1,1);
day = date.getDay();
numDaysInMonth = new Date(year, month, 0).getDate();
return Math.ceil((numDaysInMonth + day) / 7);
}
You get the day index of the first day, add it to the number of days to compensate for the number of days lost in the first week, divide by 7 and use ceil to add 1 for the simplest overflow in the next week
calcWeeksInMonth(date) {
const dateFirst = moment(date).date(1)
const dateLast = moment(date).date(date.daysInMonth())
const startWeek = dateFirst.week()
const endWeek = dateLast.week()
if (endWeek < startWeek) {
return dateFirst.weeksInYear() - startWeek + 1 + endWeek
} else {
return endWeek - startWeek + 1
}
}
This seems to output correct results, feedback welcome if there is something I missed!
This is the best way out , works well
moment.relativeTime.dd = function (number) {
// round to the closest number of weeks
var weeks = Math.round(number / 7);
if (number < 7) {
// if less than a week, use days
return number + " days";
} else {
// pluralize weeks
return weeks + " week" + (weeks === 1 ? "" : "s");
}
}
Source:How to get duration in weeks with Moment.js?
It display the list of weeks in a month with 'moment.js'.
It has been written in typescript with angular 6+.
Install moment with 'npm i moment'
Inside the ts file.
weeks_in_month() {
let year = 2019; // change year
let month = 4; // change month here
let startDate = moment([year, month - 1])
let endDate = moment(startDate).endOf('month');
var dates = [];
var weeks = [];
var per_week = [];
var difference = endDate.diff(startDate, 'days');
per_week.push(startDate.toDate())
let index = 0;
let last_week = false;
while (startDate.add(1, 'days').diff(endDate) < 0) {
if (startDate.day() != 0) {
per_week.push(startDate.toDate())
}
else {
if ((startDate.clone().add(7, 'days').month() == (month - 1))) {
weeks.push(per_week)
per_week = []
per_week.push(startDate.toDate())
}
else if (Math.abs(index - difference) > 0) {
if (!last_week) {
weeks.push(per_week);
per_week = [];
}
last_week = true;
per_week.push(startDate.toDate());
}
}
index += 1;
if ((last_week == true && Math.abs(index - difference) == 0) ||
(Math.abs(index - difference) == 0 && per_week.length == 1)) {
weeks.push(per_week)
}
dates.push(startDate.clone().toDate());
}
console.log(weeks);
}
Result:
Array of date moments.
[Array(6), Array(7), Array(7), Array(7), Array(3)]
0: (6) [Mon Apr 01 2019 00:00:00 GMT+0530 (India Standard Time),
Tue Apr 02 2019 00:00:00 GMT+0530 (India Standard Time),
Wed Apr 03 2019 00:00:00 GMT+0530 (India Standard Time),
Thu Apr 04 2019 00:00:00 GMT+0530 (India Standard Time),
Fri Apr 05 2019 00:00:00 GMT+0530 (India Standard Time),
Sat Apr 06 2019 00:00:00 GMT+0530 (India Standard Time)]
1: (7) [Sun Apr 07 2019 00:00:00 GMT+0530 (India Standard Time),
Mon Apr 08 2019 00:00:00 GMT+0530 (India Standard Time),
Tue Apr 09 2019 00:00:00 GMT+0530 (India Standard Time),
Wed Apr 10 2019 00:00:00 GMT+0530 (India Standard Time),
Thu Apr 11 2019 00:00:00 GMT+0530 (India Standard Time),
Fri Apr 12 2019 00:00:00 GMT+0530 (India Standard Time),
Sat Apr 13 2019 00:00:00 GMT+0530 (India Standard Time)]
2: (7) [Sun Apr 14 2019 00:00:00 GMT+0530 (India Standard Time),
Mon Apr 15 2019 00:00:00 GMT+0530 (India Standard Time),
Tue Apr 16 2019 00:00:00 GMT+0530 (India Standard Time),
Wed Apr 17 2019 00:00:00 GMT+0530 (India Standard Time),
Thu Apr 18 2019 00:00:00 GMT+0530 (India Standard Time),
Fri Apr 19 2019 00:00:00 GMT+0530 (India Standard Time),
Sat Apr 20 2019 00:00:00 GMT+0530 (India Standard Time)]
3: (7) [Sun Apr 21 2019 00:00:00 GMT+0530 (India Standard Time),
Mon Apr 22 2019 00:00:00 GMT+0530 (India Standard Time),
Tue Apr 23 2019 00:00:00 GMT+0530 (India Standard Time),
Wed Apr 24 2019 00:00:00 GMT+0530 (India Standard Time),
Thu Apr 25 2019 00:00:00 GMT+0530 (India Standard Time),
Fri Apr 26 2019 00:00:00 GMT+0530 (India Standard Time),
Sat Apr 27 2019 00:00:00 GMT+0530 (India Standard Time)]
4: (3) [Sun Apr 28 2019 00:00:00 GMT+0530 (India Standard Time),
Mon Apr 29 2019 00:00:00 GMT+0530 (India Standard Time),
Tue Apr 30 2019 00:00:00 GMT+0530 (India Standard Time)]
