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Find next instance of a given weekday (ie. Monday) with moment.js

I want to get the date of the next Monday or Thursday (or today if it is Mon or Thurs). As Moment.js works within the bounds of a Sunday - Saturday, I'm having to work out the current day and calculate the next Monday or Thursday based on that:
if (moment().format("dddd")=="Sunday") { var nextDay = moment().day(1); }
if (moment().format("dddd")=="Monday") { var nextDay = moment().day(1); }
if (moment().format("dddd")=="Tuesday") { var nextDay = moment().day(4); }
if (moment().format("dddd")=="Wednesday") { var nextDay = moment().day(4); }
if (moment().format("dddd")=="Thursday") { var nextDay = moment().day(4); }
if (moment().format("dddd")=="Friday") { var nextDay = moment(.day(8); }
if (moment().format("dddd")=="Saturday") { var nextDay = moment().day(8); }
This works, but surely there's a better way!

The trick here isn't in using Moment to go to a particular day from today. It's generalizing it, so you can use it with any day, regardless of where you are in the week.
First you need to know where you are in the week: moment().day(), or the slightly more predictable (in spite of locale) moment().isoWeekday(). Critically, these methods return an integer, which makes it easy to use comparison operators to determine where you are in the week, relative to your targets.
Use that to know if today's day is smaller or bigger than the day you want. If it's smaller/equal, you can simply use this week's instance of Monday or Thursday...
const dayINeed = 4; // for Thursday
const today = moment().isoWeekday();
if (today <= dayINeed) {
return moment().isoWeekday(dayINeed);
}
But, if today is bigger than the day we want, you want to use the same day of next week: "the monday of next week", regardless of where you are in the current week. In a nutshell, you want to first go into next week, using moment().add(1, 'weeks'). Once you're in next week, you can select the day you want, using moment().day(1).
Together:
const dayINeed = 4; // for Thursday
const today = moment().isoWeekday();
// if we haven't yet passed the day of the week that I need:
if (today <= dayINeed) {
// then just give me this week's instance of that day
return moment().isoWeekday(dayINeed);
} else {
// otherwise, give me *next week's* instance of that same day
return moment().add(1, 'weeks').isoWeekday(dayINeed);
}
See also https://stackoverflow.com/a/27305748/800457
EDIT: other commenters have pointed out that the OP wanted something more specific than this: the next of an array of values ("the next Monday or Thursday"), not merely the next instance of some arbitrary day. OK, cool.
The general solution is the beginning of the total solution. Instead of comparing for a single day, we're comparing to an array of days: [1,4]:
const daysINeed = [1,4]; // Monday, Thursday
// we will assume the days are in order for this demo, but inputs should be sanitized and sorted
function isThisInFuture(targetDayNum) {
// param: positive integer for weekday
// returns: matching moment or false
const todayNum = moment().isoWeekday();
if (todayNum <= targetDayNum) {
return moment().isoWeekday(targetDayNum);
}
return false;
}
function findNextInstanceInDaysArray(daysArray) {
// iterate the array of days and find all possible matches
const tests = daysINeed.map(isThisInFuture);
// select the first matching day of this week, ignoring subsequent ones, by finding the first moment object
const thisWeek = tests.find((sample) => {return sample instanceof moment});
// but if there are none, we'll return the first valid day of next week (again, assuming the days are sorted)
return thisWeek || moment().add(1, 'weeks').isoWeekday(daysINeed[0]);;
}
findNextInstanceInDaysArray(daysINeed);
I'll note that some later posters provided a very lean solution that hard-codes an array of valid numeric values. If you always expect to search the same days, and don't need to generalize for other searches, that'll be the more computationally efficient solution, although not the easiest to read, and impossible to extend.

get the next monday using moment
moment().startOf('isoWeek').add(1, 'week');

moment().day() will give you a number referring to the day_of_week.
What's even better: moment().day(1 + 7) and moment().day(4 + 7) will give you next Monday, next Thursday respectively.
See more: http://momentjs.com/docs/#/get-set/day/

The following can be used to get any next weekday date from now (or any date)
var weekDayToFind = moment().day('Monday').weekday(); //change to searched day name
var searchDate = moment(); //now or change to any date
while (searchDate.weekday() !== weekDayToFind){
searchDate.add(1, 'day');
}

Most of these answers do not address the OP's question. Andrejs Kuzmins' is the best, but I would improve on it a little more so the algorithm accounts for locale.
var nextMoOrTh = moment().isoWeekday([1,4,4,4,8,8,8][moment().isoWeekday()-1]);

Here's a solution to find the next Monday, or today if it is Monday:
const dayOfWeek = moment().day('monday').hour(0).minute(0).second(0);
const endOfToday = moment().hour(23).minute(59).second(59);
if(dayOfWeek.isBefore(endOfToday)) {
dayOfWeek.add(1, 'weeks');
}

Next Monday or any other day
moment().startOf('isoWeek').add(1, 'week').day("monday");

IMHO more elegant way:
var setDays = [ 1, 1, 4, 4, 4, 8, 8 ],
nextDay = moment().day( setDays[moment().day()] );

Here's e.g. next Monday:
var chosenWeekday = 1 // Monday
var nextChosenWeekday = chosenWeekday < moment().weekday() ? moment().weekday(chosenWeekday + 7) : moment().weekday(chosenWeekday)

The idea is similar to the one of XML, but avoids the if / else statement by simply adding the missing days to the current day.
const desiredWeekday = 4; // Thursday
const currentWeekday = moment().isoWeekday();
const missingDays = ((desiredWeekday - currentWeekday) + 7) % 7;
const nextThursday = moment().add(missingDays, "days");
We only go "to the future" by ensuring that the days added are between 0 and 6.

Parse arguments and convert it to DateTime in Javascript

The user is able to determine the parameters of a query, such as:
StartTime
EndTime
ProductId
He can set any date to StartTime and EndTime but he also wants to refer the current date something like StartTime=#Today.
He also wants to add or substract days from it such as StartTime=#Today-30 so when the query runs it will always select the last 30 days.
These parameters are processed by javascript code.
How would you parse these placeholders (#Today, #CurrentMonth, #ThisWeek, etc), convert them to DateTime and do calculations on them?

DateJS, has some very powerful functions for parsing/manipulating dates. The following excerpt is from their homepage:
// What date is next thursday?
Date.today().next().thursday();
// Add 3 days to Today
Date.today().add(3).days();
// Is today Friday?
Date.today().is().friday();
// Number fun
(3).days().ago();
// 6 months from now
var n = 6;
n.months().fromNow();
// Set to 8:30 AM on the 15th day of the month
Date.today().set({ day: 15, hour: 8, minute: 30 });
// Convert text into Date
Date.parse('today');
Date.parse('t + 5 d'); // today + 5 days
Date.parse('next thursday');
Date.parse('February 20th 1973');
Date.parse('Thu, 1 July 2004 22:30:00');
By using your own values, you will be able to write a program/function that will accomplish what you need using this library

You could use a simple regex to match them:
var date = input.replace(/#(Today|ThisWeek|CurrentMonth)([+-]\d+)?/, function(_, expr, days) {
var curr = new Date();
if (expr == "Today")
curr.setHours(0, 0, 0, 0); // to Midnight
else if (expr == "ThisWeek")
curr.setDate(curr.getDate() - ((curr.getDay()+6) % 7)); // to Monday
else if (expr == "CurrentMonth")
curr.setDate(1); // to first of month
else
return "unknown keyword";
if (days)
curr.setDate(curr.getDate() + parseInt(days, 10));
return formatDate(curr);
});
function formatDate(d) {
return d.getFullYear()+"-"+("0"+(1+d.getMonth())).slice(-2)+"-"+("0"+d.getDate()).slice(-2);
}

In Moment.js, how do you get the current financial Quarter?

Is there a simple/built in way of figuring out the current financial quarter?
ex:
Jan-Mar: 1st
Apr-Jul: 2nd
Jul-Sept: 3rd
Oct-Dec: 4th

This is now supported in moment:
moment('2014-12-01').utc().quarter() //outputs 4
moment().quarter(); //outputs current quarter ie. 2
Documentation

Using version 2.14.1+ you can do something like the following:
moment().quarter() returns the current quarter number: 1, 2, 3, 4.
moment().quarter(moment().quarter()).startOf('quarter');
Would return the current quarter with the date set to the quarter starting date.
moment().quarter(moment().quarter()).startOf('quarter');
Would return the current quarter with the date set to quarter ending date.
You could also define a function that takes the corresponding quarter number as argument (1,2,3,4), and returns an object containing the start and end date of the quarter.
function getQuarterRange(quarter) {
const start = moment().quarter(quarter).startOf('quarter');
const end = moment().quarter(quarter).endOf('quarter');
return {start, end};
}

Use this simple code to get all quarter based on january and april
Demo
Code :
// startMonth should be january or april
function setQuarter(startMonth) {
var obj = {};
if(startMonth=='january'){
obj.quarter1 = {start:moment().month(0).startOf('month'),end:moment().month(2).endOf('month')}
obj.quarter2 = {start:moment().month(3).startOf('month'),end:moment().month(5).endOf('month')}
obj.quarter3 = {start:moment().month(6).startOf('month'),end:moment().month(8).endOf('month')}
obj.quarter4 = {start:moment().month(9).startOf('month'),end:moment().month(11).endOf('month')}
console.log(obj);
return obj;
}
else if(startMonth=='april'){
obj.quarter1 = {start:moment().month(3).startOf('month'),end:moment().month(5).endOf('month')}
obj.quarter2 = {start:moment().month(6).startOf('month'),end:moment().month(8).endOf('month')}
obj.quarter3 = {start:moment().month(9).startOf('month'),end:moment().month(11).endOf('month')}
obj.quarter4 = {start:moment().month(0).startOf('month').add('years',1),end:moment().month(2).endOf('month').add('years',1)}
console.log(obj);
return obj;
}
}
setQuarter('april');
Fiddle

START DATE
moment().quarter(moment().quarter()).startOf('quarter');
Would return the current quarter with the date set to the quarter starting date.
moment("2019", "YYYY").quarter(4).startOf('quarter');
Would return the starting date of the 4th quarter of the year "2019".
moment().startOf('quarter');
Would return the starting date of the current quarter of current year.
END DATE
moment().quarter(moment().quarter()).endOf('quarter');
Would return the current quarter with the date set to quarter ending date.
moment("2019", "YYYY").quarter(4).endOf('quarter');
Would return the ending date of the 4th quarter of the year "2019".
moment().endOf('quarter');
Would return the ending date of the current quarter of current year.

I dont think any of these answers explain how to get the financial quarter. They explain how to get the calendar quarter.
I do not have a clean answer as thats what led me here. But the fiscal quarter is what is really wanted. And that is based on the start month of the fiscal year.
For example if my company's fiscal start month is February. Then at the time of writing this January 9th 2017 I'm actually in Q4 2016.
To accomplish this we need a way to get the quarter relative to a supplied integer of the start month.

There is nothing built in right now, but there is conversation to add formatting tokens for quarters. https://github.com/timrwood/moment/pull/540
In the meantime, you could use something like the following.
Math.floor(moment().month() / 3) + 1;
Or, if you want it on the moment prototype, do this.
moment.fn.quarter = function () {
return Math.floor(this.month() / 3) + 1;
}

The formula that seems to work for me is:
Math.ceil((moment().month() + 1) / 3);
moment().month() gives back the 0-11 month format so we have to add one
THE ACTUAL MONTH = (moment().month() + 1)
then we have to divide by 3 since there are 3 months in a quarter.
HOW MANY QUARTERS PASSED = (THE ACTUAL MONTH) / 3
and then we have to get the ceiling of that (round to the nearest quarter end)
CEILING(HOW MANY QUARTERS PASSED)
EDIT:
The Official formula (not commited yet) is:
~~((this.month()) / 3) + 1;
which means Math.floor((this.month()) / 3) + 1;

The simplist way to do this is
Math.floor(moment.month() / 3)
That will give you the zero based quarter index. ie 0, 1, 2, or 3.
Then, if you want the quarter's literal number, just add one.

Answer given by Nishchit Dhanani, is correct but has one issue in 'April' scenario.
Issue: If your financial year is April than, For first 3 months i.e. JAN, FEB & MAR
obj.quarter1.start date returns, 1-April-CurrentYear [incorrect Value]
obj.quarter4.end date retunrs, 31-March-NextYear [incorrect Value]
Correct values should be,
Start = 1-April-PreviuosYear
End = 31-March-CurrentYear
So, Taking consideration for first 3 month it can be written something like,
const obj = {};
/* 0-Jan, 1-Feb, 2-Mar */
if (moment().month() <= 2) {
obj.quarter1 = { start: moment().month(3).startOf('month').add('years', -1), end: moment().month(5).endOf('month').add('years', -1) };
obj.quarter2 = { start: moment().month(6).startOf('month').add('years', -1), end: moment().month(8).endOf('month').add('years', -1) };
obj.quarter3 = { start: moment().month(9).startOf('month').add('years', -1), end: moment().month(11).endOf('month').add('years', -1) };
obj.quarter4 = { start: moment().month(0).startOf('month'), end: moment().month(2).endOf('month') };
} else {
obj.quarter1 = { start: moment().month(3).startOf('month'), end: moment().month(5).endOf('month') };
obj.quarter2 = { start: moment().month(6).startOf('month'), end: moment().month(8).endOf('month') };
obj.quarter3 = { start: moment().month(9).startOf('month'), end: moment().month(11).endOf('month') };
obj.quarter4 = { start: moment().month(0).startOf('month').add('years', 1), end: moment().month(2).endOf('month').add('years', 1) };
}
console.log(obj);

Datejs calculate next and prev days in week

i use datejs and i want to get programme three buttons,
Today : generate two dates limites of this week, the monday and the sunday of thise week
Next : generate two dates limites of the next week
Prev : generate two dates limites of the prev week
here my code
var currentDay = 0;
(currentDay).days().fromNow().next().saturday().toString("yyyy-M-d");
(currentDay).days().fromNow().prev().monday().toString("yyyy-M-d");
the three buttons do
currentDay + 7; currentDay - 7; currentDay = 0;
the probléme is
we are monday 22, and this function return me the monday 15;

The following sample .getWeekRange() function accepts a Date object (or defaults to 'today'), will figure out the Monday of that week, then returns an object with a start and end property for the week.
Example
var getWeekRange = function (date) {
var date = date || Date.today(),
start = date.is().monday() ? date : date.last().monday(),
end = start.clone().next().sunday();
return {
start : start,
end : end
};
};
You can then use the function to acquire the week range for any given Date:
Example
var range = getWeekRange();
console.log("Start", range.start);
console.log("End", range.end);
To get the previous week, just pass in a Date object from the previous week:
Example
var prev = getWeekRange(Date.today().last().week());
To get the next week, just pass in a Date object from the next week:
Example
var next = getWeekRange(Date.today().next().week());
Hope this helps.

I've written some code for this sometime ago:
Date.prototype.getMonday=function(){return this.getDay()==1 ? this.clone().clearTime() : this.clone().prev().monday().clearTime();};
// This function returns the Monday of current week
var today=new Date();
today.getMonday().toString();
today.getMonday().next().sunday().toString();
// start and end of this week
today.getMonday().prev().monday().toString();
today.getMonday().prev().day().toString();
// previous week
today.getMonday().next().monday().toString();
today().getMonday().next().sunday().sunday().toString();
// next week
May these help.

Simple javascript date math... not really

I am trying to create a simple script that gives me the next recycling date based on a biweekly schedule starting on Wed Jul 6, 2011. So I've created this simple function...
function getNextDate(startDate) {
if (today <= startDate) {
return startDate;
}
// calculate the day since the start date.
var totalDays = Math.ceil((today.getTime()-startDate.getTime())/(one_day));
// check to see if this day falls on a recycle day
var bumpDays = totalDays%14; // mod 14 -- pickup up every 14 days...
// pickup is today
if (bumpDays == 0) {
return today;
}
// return the closest day which is in 14 days, less the # of days since the last
// pick up..
var ms = today.getTime() + ((14- bumpDays) * one_day);
return new Date(ms);
}
and can call it like...
var today=new Date();
var one_day=1000*60*60*24; // one day in milliseconds
var nextDate = getNextDate(new Date(2011,06,06));
so far so good... but when I project "today" to 10/27/2011, I get Tuesday 11/8/2011 as the next date instead of Wednesday 11/9/2011... In fact every day from now thru 10/26/2011 projects the correct pick-up... and every date from 10/27/2011 thru 2/28/2012 projects the Tuesday and not the Wednesday. And then every date from 2/29/2012 (leap year) thru 10/24/2012 (hmmm October again) projects the Wednesday correctly. What am I missing? Any help would be greatly appreciated..
V

The easiest way to do this is update the Date object using setDate. As the comments for this answer indicate this isn't officially part of the spec, but it is supported on all major browsers.
You should NEVER update a different Date object than the one you did the original getDate call on.
Sample implementation:
var incrementDate = function (date, amount) {
var tmpDate = new Date(date);
tmpDate.setDate(tmpDate.getDate() + amount)
return tmpDate;
};
If you're trying to increment a date, please use this function. It will accept both positive and negative values. It also guarantees that the used date objects isn't changed. This should prevent any error which can occur if you don't expect the update to change the value of the object.
Incorrect usage:
var startDate = new Date('2013-11-01T11:00:00');
var a = new Date();
a.setDate(startDate.getDate() + 14)
This will update the "date" value for startDate with 14 days based on the value of a. Because the value of a is not the same is the previously defined startDate it's possible to get a wrong value.

Expanding on Exellian's answer, if you want to calculate any period in the future (in my case, for the next pay date), you can do a simple loop:
var today = new Date();
var basePayDate = new Date(2012, 9, 23, 0, 0, 0, 0);
while (basePayDate < today) {
basePayDate.setDate(basePayDate.getDate()+14);
}
var nextPayDate = new Date(basePayDate.getTime());
basePayDate.setDate(nextPayDate.getDate()-14);
document.writeln("<p>Previous pay Date: " + basePayDate.toString());
document.writeln("<p>Current Date: " + today.toString());
document.writeln("<p>Next pay Date: " + nextPayDate.toString());
This won't hit odd problems, assuming the core date services work as expected. I have to admit, I didn't test it out to many years into the future...

Note: I had a similar issue; I wanted to create an array of dates on a weekly basis, ie., start date 10/23/2011 and go for 12 weeks. My code was more or less this:
var myDate = new Date(Date.parse(document.eventForm.startDate.value));
var toDate = new Date(myDate);
var week = 60 * 60 * 24 * 7 * 1000;
var milliseconds = toDate.getTime();
dateArray[0] = myDate.format('m/d/Y');
for (var count = 1; count < numberOccurrences; count++) {
milliseconds += week;
toDate.setTime(milliseconds);
dateArray[count] = toDate.format('m/d/Y');
}
Because I didn't specify the time and I live in the US, my default time was midnight, so when I crossed the daylight savings time border, I moved into the previous day. Yuck. I resolved it by setting my time of day to noon before I did my week calculation.