# Ordinal day of Year needed
**URL:** https://discourse.nodered.org/t/ordinal-day-of-year-needed/96886
**Category:** General
**Created:** [4 May 2025 20:09 UTC](https://discourse.nodered.org/t/ordinal-day-of-year-needed/96886 "2025-05-04T20:09:52Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@larkingabout](https://discourse.nodered.org/u/larkingabout)
#### Post date: [4 May 2025 20:09 UTC](https://discourse.nodered.org/t/ordinal-day-of-year-needed/96886/1 "2025-05-04T20:09:52Z")
Im running an older V0.19.5 Node Red instance on a PI-0-W with the Stretch version of the pi-os,
I know i should have been updating, but its been running flawlessly mostly handling mqtt for basic automation.
Its been decades since i approached the code-face for anything but a lil fun and distraction,
and re-flashing a new up to date system sd card and reconfiguring my basic set up with a later version of node red which will enable pallate updates is on the cards, but meanwhile i would like to solve this.
I needed to make a slight modification to the watering schedule for the patio tomatoes as to not drown them while growing, and i decided to water on alternative days so
Mod(ordinalDayofyear/2) is my key condition.
I was expecting to find a date object with ordinal day of year as a basic property, its not??
Im currently working with mod(day of month/2) but with a 29 or 31 day month I will get numerous double watering days per anum, now granted not too crucial when it comes to tomatoes but still, its not good enough.
I can see how to sum the current day of month with the day count of earlier months in the current year, but that seems a bit naff too
IM using the inject node timestamp as my date source. this starts the flow at a regular interval,
my function node returns the odd even day evaluation of mod(dayofmonth/2) to a switch node that passes onto a mqtt-create change node to start watering for X minutes..
Thanks in advance if you can advise..
---
### Author:  [@larkingabout](https://discourse.nodered.org/u/larkingabout)
#### Post date: [4 May 2025 21:03 UTC](https://discourse.nodered.org/t/ordinal-day-of-year-needed/96886/2 "2025-05-04T21:03:28Z")
and sorted..
```auto
const aDay = 1000 * 60 * 60 * 24;
var dt = new Date(msg.payload);
var st = new Date();
var DayOfYear = 0;
st.setDate(1);
st.setMonth(0);
st.setHours(0);
st.setMinutes(0);
st.setSeconds(0);
st.setMilliseconds(0);
DayOfYear = Math.trunc((dt.getTime() - st.getTime())/ aDay) + 1;
msg.payload = DayOfYear;
return msg;
```
Cheers..
---
### Author:  [@bakman2](https://discourse.nodered.org/u/bakman2)
#### Post date: [4 May 2025 21:15 UTC](https://discourse.nodered.org/t/ordinal-day-of-year-needed/96886/3 "2025-05-04T21:15:47Z")
I think you should be able to use this short version
```auto
const dayOfYear = (date) =>
Math.floor((date - new Date(date.getFullYear(), 0, 0)) / 1000 / 60 / 60 / 24);
const result = dayOfYear(msg.payload);
```
---
### Author:  [@E1cid](https://discourse.nodered.org/u/E1cid)
#### Post date: [4 May 2025 21:36 UTC](https://discourse.nodered.org/t/ordinal-day-of-year-needed/96886/4 "2025-05-04T21:36:54Z")
Or alternate days output 0 or 1, from an input of epoch timestamp.
```auto
msg.payload = Math.floor(msg.payload / 86400000) % 2;
```
---
### Author:  [@larkingabout](https://discourse.nodered.org/u/larkingabout)
#### Post date: [4 May 2025 23:07 UTC](https://discourse.nodered.org/t/ordinal-day-of-year-needed/96886/5 "2025-05-04T23:07:03Z")
Thanks ,both are much more elegant than my plod though. Easy when your shown 😉
- It seems the install on the pi-0-w isnt the headache it was either..
arm6 and 7 core differences iirc no longer an issue phew!.
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [2 August 2025 23:07 UTC](https://discourse.nodered.org/t/ordinal-day-of-year-needed/96886/6 "2025-08-02T23:07:08Z")
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