These are mine favoured functions in a program language.
Therefore I have both the conversion in .js form.
They are written in a function form.
function YMDtoJulian(Year, Month, Day)
In lot of questions I found that working with numbers of day in between dates or every x day further becomes easier to put the Julian-day number on 00:00 as a variable.
Then read it, with adding or subtracting number of days, with a homey-script back to a date when you needed.
Now can I put those to functions here, but I don’t know if that is not against the rules.