rs-date-utils

Date and time utilities — business days, date ranges, holiday calendars, and formatting shortcuts

Installation

[dependencies]
philiprehberger-date-utils = "0.1.3"

Usage

use chrono::NaiveDate;
use philiprehberger_date_utils::{
    add_business_days, business_days_between, is_business_day,
    next_business_day, USFederalCalendar, NoHolidayCalendar,
};

let cal = USFederalCalendar;
let date = NaiveDate::from_ymd_opt(2026, 3, 19).unwrap(); // Thursday

// Add 5 business days (skips weekends and holidays)
let future = add_business_days(date, 5, &cal);

// Count business days between two dates
let count = business_days_between(
    NaiveDate::from_ymd_opt(2026, 3, 16).unwrap(),
    NaiveDate::from_ymd_opt(2026, 3, 23).unwrap(),
    &cal,
);

// Check if a date is a business day
assert!(is_business_day(date, &cal));

// Get the next business day
let next = next_business_day(date, &cal);

Holiday Calendars

use chrono::NaiveDate;
use philiprehberger_date_utils::{HolidayCalendar, USFederalCalendar};

let cal = USFederalCalendar;

// Check if a date is a holiday
let christmas = NaiveDate::from_ymd_opt(2026, 12, 25).unwrap();
assert!(cal.is_holiday(christmas));

// Get all holidays in a year
let holidays = cal.holidays_in_year(2026);
assert_eq!(holidays.len(), 11);

Date Ranges

use chrono::NaiveDate;
use philiprehberger_date_utils::{DateRange, NoHolidayCalendar};

let start = NaiveDate::from_ymd_opt(2026, 3, 1).unwrap();
let end = NaiveDate::from_ymd_opt(2026, 3, 31).unwrap();
let range = DateRange::new(start, end);

// Iterate over days
for date in range.iter_days() {
    // ...
}

// Iterate over weeks
for week_start in range.iter_weeks() {
    // ...
}

// Check containment and overlap
assert!(range.contains(NaiveDate::from_ymd_opt(2026, 3, 15).unwrap()));
assert_eq!(range.days_count(), 31);

let cal = NoHolidayCalendar;
let biz_days = range.business_days_count(&cal);

Formatting

use chrono::NaiveDate;
use philiprehberger_date_utils::{format_long, format_short, format_iso};

let date = NaiveDate::from_ymd_opt(2026, 3, 19).unwrap();

assert_eq!(format_long(date), "March 19, 2026");
assert_eq!(format_short(date), "Mar 19, 2026");
assert_eq!(format_iso(date), "2026-03-19");

Quarter and Fiscal Year

use chrono::NaiveDate;
use philiprehberger_date_utils::{quarter, fiscal_year, years_between};

let date = NaiveDate::from_ymd_opt(2026, 3, 19).unwrap();

assert_eq!(quarter(date), 1);
assert_eq!(fiscal_year(date, 10), 2025); // October fiscal year start

let birth = NaiveDate::from_ymd_opt(2000, 3, 19).unwrap();
assert_eq!(years_between(birth, date), 26);

Month and Quarter Boundaries

use chrono::NaiveDate;
use philiprehberger_date_utils::{
    start_of_month, end_of_month, start_of_quarter, end_of_quarter,
};

let date = NaiveDate::from_ymd_opt(2026, 3, 19).unwrap();

assert_eq!(start_of_month(date), NaiveDate::from_ymd_opt(2026, 3, 1).unwrap());
assert_eq!(end_of_month(date), NaiveDate::from_ymd_opt(2026, 3, 31).unwrap());
assert_eq!(start_of_quarter(date), NaiveDate::from_ymd_opt(2026, 1, 1).unwrap());
assert_eq!(end_of_quarter(date), NaiveDate::from_ymd_opt(2026, 3, 31).unwrap());

API

Function / Type	Description
HolidayCalendar	Trait for holiday calendars with is_holiday() and holidays_in_year()
USFederalCalendar	US federal holidays with weekend adjustment rules
NoHolidayCalendar	Empty calendar — no holidays
add_business_days(date, days, cal)	Add or subtract business days, skipping weekends and holidays
business_days_between(start, end, cal)	Count business days between two dates (end exclusive)
is_business_day(date, cal)	Check if a date is a business day
next_business_day(date, cal)	Get the next business day after a date
DateRange::new(start, end)	Create an inclusive date range
range.iter_days()	Iterate over every day in the range
range.iter_weeks()	Iterate over week-start dates in the range
range.contains(date)	Check if a date is within the range
range.overlaps(other)	Check if two ranges overlap
range.days_count()	Total days in the range (inclusive)
range.business_days_count(cal)	Business days in the range (inclusive)
quarter(date)	Get the quarter (1-4) for a date
fiscal_year(date, start_month)	Get the fiscal year based on a custom start month
years_between(from, to)	Full years between two dates (age calculation)
format_long(date)	Format as "March 19, 2026"
format_short(date)	Format as "Mar 19, 2026"
format_iso(date)	Format as "2026-03-19"
start_of_month(date)	First day of the month
end_of_month(date)	Last day of the month
start_of_quarter(date)	First day of the quarter
end_of_quarter(date)	Last day of the quarter

Development

cargo test
cargo clippy -- -D warnings

Support

If you find this project useful:

⭐ Star the repo

🐛 Report issues

💡 Suggest features

❤️ Sponsor development

🌐 All Open Source Projects

💻 GitHub Profile

🔗 LinkedIn Profile

License

MIT