Develop Reference

How to get starting and ending days of each month in a date interval in js

i'm looking for a function which takes as parameters a starting and an ending date that returns an array of each first/ending days for each months in this interval.
Expected :
myFunction(new Date('2021-02-06'), new Date('2021-04-24'))
Expected output :
[
{begin: '2021-02-06', end: '2021-02-28' },
{begin: '2021-03-01', end: '2021-03-31' },
{begin: '2021-04-01', end: '2021-04-24' },
]

You can use next code:
myFunction(new Date('2021-02-06'), new Date('2021-04-24'));
function myFunction(startDateInput, endDateInput) {
var monthDifference = monthDiff(startDateInput, endDateInput)
var dates = [];
for (var i = 0; i <= monthDifference; i++) {
var month = startDateInput.getMonth();
var year = startDateInput.getFullYear();
// this gets first day in month
var startDate = new Date(year, month + i, 1)
// this gets last day in month
var endDate = new Date(year, month + i + 1, 0)
console.log('startDate', startDate);
console.log('endDate', endDate);
dates.push(
{
begin : startDate,
end : endDate
}
)
}
// this is to overwrite first and last date in array, it can be done better
dates[0].begin = startDateInput;
dates[monthDifference].end = endDateInput;
console.log('dates', dates)
}
function monthDiff(d1, d2) {
var months;
months = (d2.getFullYear() - d1.getFullYear()) * 12;
months -= d1.getMonth();
months += d2.getMonth();
return months <= 0 ? 0 : months;
}
Of course you can improve this code further. I made it quickly.

const formatDateString = (date) => {
const leadingZero = (d) => (100 + d + '').substr(1);
const y = date.getFullYear();
const m = leadingZero(date.getMonth() + 1);
const d = leadingZero(date.getDate());
return `${y}-${m}-${d}`;
};
const myFunction = (startIn, endIn) => {
const monthDifference = monthsDist(startIn, endIn);
const res = [];
const startYear = startIn.getFullYear();
const startMonth = startIn.getMonth();
const startDate = startIn.getDate();
for (let deltaM = 0; deltaM <= monthDifference; deltaM++) {
const monthStart = new Date(
startYear,
startMonth + deltaM,
deltaM ? 1 : startDate
);
const monthEnd =
deltaM < monthDifference ?
new Date(startYear, startMonth + deltaM + 1, 0) :
endIn;
res.push({
begin: formatDateString(monthStart),
end: formatDateString(monthEnd),
});
}
return res;
};
const monthsDist = (start, end) => {
const diffM =
(end.getFullYear() - start.getFullYear()) * 12 +
end.getMonth() -
start.getMonth();
return diffM > 0 ? diffM : 0;
};
console.log(myFunction(new Date('2021-02-06'), new Date('2021-04-24')));
console.log(myFunction(new Date('2020-02-06'), new Date('2021-04-24')));
console.log(myFunction(new Date('2021-04-06'), new Date('2021-04-24')));

How to get minutes in between two different dates?

Hi i am using Javascript and i want to get each and every minute between two dates for example:
firstDate: 2019-04-02 02:03:00
secondDate: 2019-04-03 03:04:00
So my final output result should return like this:
2019-04-02 02:03:00
2019-04-02 02:04:00
2019-04-02 02:05:00
.
.
.
2019-04-03 03:04:00
Here is the code which i tried
var boxingDay = new Date("2019-04-02 02:03:00");
var nextWeek = new Date("2019-04-03 03:04:00");
function getDatesRange(startDate, stopDate){
const ONE_DAY = 60*1000;
var days= [];
var currentDate = new Date(startDate);
while (currentDate <= stopDate) {
days.push(new Date (currentDate));
currentDate = currentDate - 1 + 1 + ONE_DAY;
}
return days.join("\n");
}
console.log(getDatesRange(boxingDay,nextWeek))
/* var map = getDates(boxingDay, nextWeek).map((times) => {
console.log(Date.parse(times))
}) */
/* console.log((getDates( boxingDay, nextWeek ))); */
The problem is I am getting correct output but I need in the form of an array, like below and reuse the function if I am reusing, it returns me an empty array.
[[2019-04-02 02:03:00],[2019-04-02 02:04:00].....]
Any solution TIA.

Using your code as a basis, you can do this as follows (note that I'm using .toISOString(), you can change this according to your needs):
const boxingDay = new Date("2019-04-02 02:03:00");
const nextWeek = new Date("2019-04-03 03:04:00");
function getDatesRange(startDate, stopDate){
const ONE_MINUTE = 60*1000;
const days= [];
let currentDate = new Date(startDate);
while (currentDate <= stopDate) {
days.push([currentDate.toISOString()]);
currentDate.setTime(currentDate.getTime() + ONE_MINUTE);
}
return days;
}
console.log(getDatesRange(boxingDay,nextWeek));

There is a way, that you could use while loop with format function, each iteration increate the minute
const firstDate = new Date('2019-04-02 02:03:00')
const secondDate = new Date('2019-04-03 03:04:00')
const formatDate = dateObj => {
const year = String(dateObj.getFullYear()).padStart(4, '0')
const month = String(dateObj.getMonth() + 1).padStart(2, '0')
const date = String(dateObj.getDate()).padStart(2, '0')
const hour = String(dateObj.getHours()).padStart(2, '0')
const minute = String(dateObj.getMinutes()).padStart(2, '0')
const second = String(dateObj.getSeconds()).padStart(2, '0')
return `${year}-${month}-${date} ${hour}:${minute}:${second}`
}
const res = []
const iteratedDate = new Date(firstDate.getTime())
while (iteratedDate <= secondDate) {
res.push(formatDate(iteratedDate))
iteratedDate.setMinutes(iteratedDate.getMinutes() + 1)
}
// res array is large so I sliced the first 10 amd the last 10
console.log(res.slice(0, 10))
console.log(res.slice(res.length - 10))

A slightly different approach using a for loop; it also avoids creating a new Date instance for each minute iterated.
const p = new Date("2019-04-02T23:57:00");
const q = new Date("2019-04-03T00:03:00");
const r = [];
for(const d = new Date(p); d <= q; d.setTime(d.getTime() + 60000))
{
r.push(d.toISOString().substring(0, 19).replace(/T/, " "));
}
const s = r.join("\n");
console.log(s);

How to find between 2 dates whichever comes first

I tried to find someone between 2 dates earlier in the year or month and it didn't work
converteDateToDatePipe(dCheck: Date, d1: Date): boolean {
var d11 = this.pipe.transform(d1, 'shortDate');
var dCc = this.pipe.transform(dCheck, 'shortDate');
var dd11 = new Date(d11);
var ddcc = new Date(dCc);
if (dd11 <= ddcc)
return true;
else
return false;
}

test(){
let first = new Date(new Date().getTime() + 111111);
let second = new Date(new Date().getTime() + 22222);
let nextDate = this.nextDate(first, second);
console.log(second.getTime() === nextDate.getTime())
}
nextDate(first: Date, second: Date): Date {
let currentDay = new Date();
let firstDiff = currentDay.getTime() - first.getTime();
let secondDiff = currentDay.getTime() - second.getTime();
return (firstDiff >= secondDiff) ? first : second;
}

How can I use moment.js to add days, excluding weekends?

I'm setting a default follow-up date two days from current date, which currently works:
const Notify = moment().add(2, 'days').toDate();
However, I would like to exclude weekends. So I installed moment WeekDay, but I can't seem to get it to work with adding days to the current date. The documentation calls for:
moment().weekday(0)
But I can't get that to work with adding in two days forward. Any ideas?

This solution is simple, easy to follow, and works well for me:
function addBusinessDays(originalDate, numDaysToAdd) {
const Sunday = 0;
const Saturday = 6;
let daysRemaining = numDaysToAdd;
const newDate = originalDate.clone();
while (daysRemaining > 0) {
newDate.add(1, 'days');
if (newDate.day() !== Sunday && newDate.day() !== Saturday) {
daysRemaining--;
}
}
return newDate;
}

Try: moment-business-days
It should help you.
Example:
var momentBusinessDays = require("moment-business-days")
momentBusinessDays('20-09-2018', 'DD-MM-YYYY').businessAdd(3)._d
Result:
Tue Sep 25 2018 00:00:00 GMT+0530 (IST)

You could also not use external lib and do a simple function like one of these two:
const WEEKEND = [moment().day("Saturday").weekday(), moment().day("Sunday").weekday()]
const addBusinessDays1 = (date, daysToAdd) => {
var daysAdded = 0,
momentDate = moment(new Date(date));
while (daysAdded < daysToAdd) {
momentDate = momentDate.add(1, 'days');
if (!WEEKEND.includes(momentDate.weekday())) {
daysAdded++
}
}
return momentDate;
}
console.log(addBusinessDays1(new Date(), 7).format('MM/DD/YYYY'))
console.log(addBusinessDays1('09-20-2018', 3).format('MM/DD/YYYY'))
// This is the somewhat faster version
const addBusinessDays2 = (date, days) => {
var d = moment(new Date(date)).add(Math.floor(days / 5) * 7, 'd');
var remaining = days % 5;
while (remaining) {
d.add(1, 'd');
if (d.day() !== 0 && d.day() !== 6)
remaining--;
}
return d;
};
console.log(addBusinessDays2(new Date(), 7).format('MM/DD/YYYY'))
console.log(addBusinessDays2('09-20-2018', 3).format('MM/DD/YYYY'))
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.22.2/moment.min.js"></script>
They are slightly modified from this post and I think are a good alternative to external library you have to carry/deal with (assuming this is the only part you need and not other features of that lib).

This will do it based on any starting date, and without a costly loop. You calculate the number of weekend days you need to skip over, then just offset by the number of weekdays and weekends, together.
function addWeekdays(year, month, day, numberOfWeekdays) {
var originalDate = year + '-' + month + '-' + day;
var futureDate = moment(originalDate);
var currentDayOfWeek = futureDate.day(); // 0 = Sunday, 1 = Monday, ..., 6 = Saturday
var numberOfWeekends = Math.floor((currentDayOfWeek + numberOfWeekdays - 1) / 5); // calculate the number of weekends to skip over
futureDate.add(numberOfWeekdays + numberOfWeekends * 2, 'days'); // account for the 2 days per weekend
return futureDate;
}

const addWorkingDays = (date: Moment, days: number) => {
let newDate = date.clone();
for (let i = 0; i < days; i++) {
if (newDate.isoWeekday() !== 6 && newDate.isoWeekday() !== 7) {
newDate = newDate.add(1, "days");
} else {
newDate = newDate.add(1, "days");
i--;
}
}
return newDate.format("YYYY/MM/DD");
};

var moment = require("moment")
function addWorkingDay(date, days){
let daysToAdd = days
const today = moment(date);
const nextWeekStart = today.clone().add(1, 'week').weekday(1);
const weekEnd = today.clone().weekday(5);
const daysTillWeekEnd = Math.max(0, weekEnd.diff(today, 'days'));
if(daysTillWeekEnd >= daysToAdd) return today.clone().add(daysToAdd, 'days');
daysToAdd = daysToAdd - daysTillWeekEnd - 1;
return nextWeekStart.add(Math.floor(daysToAdd/5), 'week').add(daysToAdd % 5, 'days')
}

I think this code will be faster:
var businessDays = 10;
var days = businessDays + Math.floor((Math.min(moment().day(),5)+businessDays)/6)*2;
moment.add(days, 'days');

// using pure JS
function addBusinessDays(originalDate, numDaysToAdd) {
const Sunday = 0;
const Saturday = 6;
let daysRemaining = numDaysToAdd;
const newDate = originalDate;
while (daysRemaining > 0) {
newDate.setDate(newDate.getDate() + 1);
if (newDate.getDay() !== 0 && newDate.getDay() !== 6) {
// skip sunday & saturday
daysRemaining--;
}
}
return newDate;
}
var dt = new Date(); // get date
var business_days = 8;
newDate = addBusinessDays(dt, business_days);
console.log(newDate.toString());

JavaScript: get all months between two dates?

I have two date strings like this:
var startDate = '2012-04-01';
var endDate = '2014-11-01';
And I want to end up with an array of strings like this:
var dates = ['2012-04-01', '2012-05-01', '2012-06-01' .... '2014-11-01',];
So far this is what I've got, but it's pretty ugly:
var startDate = '2012-04-01';
var endDate = '2014-11-01';
var start = new Date(Date.parse(startDate));
var end = new Date(Date.parse(endDate))
var dates = [];
for (var i = start.getFullYear(); i < end.getFullYear() + 1; i++) {
dates.push(i + '-' + '-01');
}
console.log(dates);
Is there a better way? JSFiddle.

This should produce the desired output:
function dateRange(startDate, endDate) {
var start = startDate.split('-');
var end = endDate.split('-');
var startYear = parseInt(start[0]);
var endYear = parseInt(end[0]);
var dates = [];
for(var i = startYear; i <= endYear; i++) {
var endMonth = i != endYear ? 11 : parseInt(end[1]) - 1;
var startMon = i === startYear ? parseInt(start[1])-1 : 0;
for(var j = startMon; j <= endMonth; j = j > 12 ? j % 12 || 11 : j+1) {
var month = j+1;
var displayMonth = month < 10 ? '0'+month : month;
dates.push([i, displayMonth, '01'].join('-'));
}
}
return dates;
}
Just call it with your existing date format:
dateRange('2013-11-01', '2014-06-01')
// ["2013-11-01", "2013-12-01", "2014-01-01", "2014-02-01", "2014-03-01", "2014-04-01", "2014-05-01", "2014-06-01", "2014-07-01", "2014-08-01", "2014-09-01", "2014-10-01", "2014-11-01", "2014-12-01"]

You can also use the excellent moment.js library:
var startDate = moment('2012-04-01');
var endDate = moment('2014-11-01');
var result = [];
if (endDate.isBefore(startDate)) {
throw "End date must be greated than start date."
}
while (startDate.isBefore(endDate)) {
result.push(startDate.format("YYYY-MM-01"));
startDate.add(1, 'month');
}
JSFiddle

If loading an extra library isn't a problem, you could always try the awesome MomentJS.
Gives for very clean and powerful date manipulation.
var startDate = moment('2012-04-01');
var endDate = moment('2014-11-01');
var dates = [];
endDate.subtract(1, "month"); //Substract one month to exclude endDate itself
var month = moment(startDate); //clone the startDate
while( month < endDate ) {
month.add(1, "month");
dates.push(month.format('YYYY-MM-DD'));
}
console.log(dates);
JSFiddle here

const getMonths = (fromDate, toDate) => {
const fromYear = fromDate.getFullYear();
const fromMonth = fromDate.getMonth();
const toYear = toDate.getFullYear();
const toMonth = toDate.getMonth();
const months = [];
for(let year = fromYear; year <= toYear; year++) {
let monthNum = year === fromYear ? fromMonth : 0;
const monthLimit = year === toYear ? toMonth : 11;
for(; monthNum <= monthLimit; monthNum++) {
let month = monthNum + 1;
months.push({ year, month });
}
}
return months;
}
const sample = getMonths(new Date('2022-07-28'), new Date('2023-03-20'));
console.log(sample);
document.write('check the console output');
https://jsfiddle.net/xfayoqvs/

You are handling "logical" jumps, so you doesn't actually need timing arthmetics. So this is a simple counting problem:
var startDate = '2012-04-01';
var endDate = '2014-11-01';
var dates = [];
var d0 = startDate.split('-');
var d1 = endDate.split('-');
for (
var y = d0[0];
y <= d1[0];
y++
) {
for (
var m = d0[1];
m <= 12;
m++
) {
dates.push(y+"-"+m+"-1");
if (y >= d1[0] && m >= d1[1]) break;
};
d0[1] = 1;
};
console.log(dates);

Here is a solution which just uses string manipulation on that specific YYYY-MM-DD format:
function monthsBetween(...args) {
let [a, b] = args.map(arg => arg.split("-").slice(0, 2)
.reduce((y, m) => m - 1 + y * 12));
return Array.from({length: b - a + 1}, _ => a++)
.map(m => ~~(m / 12) + "-" + ("0" + (m % 12 + 1)).slice(-2) + "-01");
}
console.log(monthsBetween('2012-04-01', '2014-11-01'));

Here is another solution, using Date objects:
const enumerateMonths = (from, to) => {
const current = new Date(from)
current.setUTCDate(1)
current.setUTCHours(0, 0, 0, 0)
const toDate = new Date(to)
const months = []
while (current.getTime() <= toDate.getTime()) {
months.push(current.getUTCFullYear() + "-" + `${current.getUTCMonth() + 1}`.padStart(2, "0"))
current.setUTCMonth(current.getUTCMonth() + 1)
}
return months
}
This solution presumes you provide Date objects or ISO 8601 strings. Please mind that an ISO 8601 date does not necessarily have to contain the hours-minutes-seconds part. "2012-01-14" is a valid ISO 8601 date.

An example to get all first days of months between a given date and now using moment.js.
var getMonths = function (startDate) {
var dates = [];
for (var year = startDate.year(); year <= moment().year(); year++) {
var endMonth = year != moment().year() ? 11 : moment().month();
var startMonth = year === startDate.year() ? startDate.month() : 0;
for (var currentMonth = startMonth; currentMonth <= endMonth; currentMonth = currentMonth > 12 ? currentMonth % 12 || 11 : currentMonth + 1) {
var month = currentMonth + 1;
var displayMonth = month < 10 ? '0' + month : month;
dates.push([year, displayMonth, '01'].join('-'));
}
}
return dates;
};

All solutions above run in O(n^2) time complexity, which is not very efficient.
See below solution in O(n) time complexity:
function getAllMonths(start, end){
let startDate = new Date(start);
let startYear = startDate.getFullYear();
let startMonth = startDate.getMonth()+1;
let endDate = new Date(end);
let endYear = endDate.getFullYear();
let endMonth = endDate.getMonth()+1;
let countMonth = 0;
let countYear = 0;
let finalResult = [];
for(let a=startYear; a<=endYear; a++){
if(startYear<endYear){
if(countYear==0){
countMonth += 12-startMonth;
}else
if(countYear>0){
countMonth += 12;
}
countYear+=1;
startYear++;
}else
if(startYear==endYear){
countMonth+=endMonth;
}
}
for(let i=startMonth; i<=countMonth+startMonth; i++){
finalResult.push(startDate.getFullYear()+(Math.floor(i/12)) + "-" + Math.round(i%13) + "-" + "01");
}
return finalResult;
}
getAllMonths('2016-04-01', '2018-01-01');
Might share a much more simpler code

Still not a very elegant answer, but arrives at the array of strings you want:
var startDate = '2012-04-01';
var endDate = '2014-11-01';
var start = new Date(startDate);
var end = new Date(endDate);
var dates = [];
for (var i = start.getFullYear(); i < end.getFullYear() + 1; i++) {
for (var j = 1; j <= 12; j++) {
if (i === end.getFullYear() && j === end.getMonth() + 3) {
break;
}
else if (i === 2012 && j < 4){
continue;
}
else if (j < 10) {
var dateString = [i, '-', '0' + j, '-','01'].join('');
dates.push(dateString)
}
else {
var dateString = [i, '-', j, '-','01'].join('');
dates.push(dateString);
}
}
}
console.log(dates);
jsfiddle link here: http://jsfiddle.net/8kut035a/

This is my solution, with help of math and O(n)
determineMonthInInterval(startDate, endDate) {
let startYear = startDate.getFullYear();
let endYear = endDate.getFullYear();
let startMonth = startDate.getMonth() + 1;
let endMonth = endDate.getMonth() + 1;
let monthAmount = (endMonth - startMonth) + 1 + (12 * (endYear - startYear));
let dates = [];
let currMonth = startMonth;
let currYear = startYear;
for( let i=0; i<monthAmount; i++){
let date = new Date(currYear + "/"+currMonth+"/1");
dates.push(date);
currYear = startYear + Math.floor((startMonth+i) / 12);
currMonth = (currMonth) % 12 +1;
}
return dates;
}

Here is another option:
getRangeOfMonths(startDate: Date, endDate: Date) {
const dates = new Array<string>();
const dateCounter = new Date(startDate);
// avoids edge case where last month is skipped
dateCounter.setDate(1);
while (dateCounter < endDate) {
dates.push(`${dateCounter.getFullYear()}-${dateCounter.getMonth() + 1}`);
dateCounter.setMonth(dateCounter.getMonth() + 1);
}
return dates;
}