time_plus 1.1.5

Extensions for DateTime and Duration to easily add, convert, and work with time in Dart.

Make every microsecond count.

Stop wrestling with DateTime and Duration. time_plus gives you the tools you wish Dart had built in—add time units, break durations down, convert across scales, and do it all with a clear, predictable API. No dependencies. Just useful extensions that make working with time easier.

Table of Contents

📅 DateTime

• add – Add time units to DateTime from milliseconds to centuries with .addX() or .addX getters.
• isSame – Compare two dates by year, month, day, hour, to microseconds using isSameX().
• startOf / endOf – Get start or end of time units: minute, hour, day, week, month, year.
• leap – Check if DateTime is in a leap year, leap month, or on leap day (Feb 29).
• yesterday / tomorrow – Get yesterday or tomorrow with .yesterday or .tomorrow getters.

⏱️ Duration

• add – Chain any time unit, from microseconds to centuries, with .addX() or .addX getters.
• in – Convert durations into whole units like inWeeks, inYears, or inCenturies.
• only – Extract the remainder after subtracting larger units (e.g. onlyMinutes, onlySeconds).
• without – Strip full units to isolate what’s left (e.g. time since midnight).
• Factories – Create durations from any unit or use built-in constants like DurationFrom.year.

Why Use time_plus?

✅ Zero dependencies – Pure Dart. No setup, no third-party overhead.
✅ Lightweight & efficient – Minimal footprint with production-safe performance.
✅ Powerful time utilities – Add, compare, normalize, and decompose time with confidence.
✅ Production-grade & tested – Built for reliability with thorough test coverage.

• Ideal for:
  • 🗓 Calendar logic – Scheduling, planning, date math, and recurring events
  • 🧮 Data handling – Grouping, filtering, and comparing DateTime objects with precision
  • ⏱️ UI & analytics – Formatting durations, tracking activity, and displaying time intuitively

time_plus closes the gaps in Dart’s native DateTime and Duration APIs — making your code easier to write, easier to read, and easier to trust.

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➕ add — Add Time to a DateTime

Extend DateTime just like you wish it worked. These extensions let you safely add milliseconds, hours, days, months, and even centuries — with proper handling for leap years and end-of-month overflows.

• addMilliseconds(int) / addMillisecond
• addSeconds(int) / addSecond
• addMinutes(int) / addMinute
• addHours(int) / addHour
• addDays(int) / addDay
• addWeeks(int) / addWeek
• addMonths(int) / addMonth
• addYears(int) / addYear
• addDecades(int) / addDecade (10-year spans)
• addCenturies(int) / addCentury (100-year spans)

All methods return a new DateTime instance. Month and year-based methods clamp invalid dates (e.g. Feb 30 → Feb 28/29), ensuring always-valid results.

🧪 Example

final now = DateTime(2024, 2, 29);
final nextYear = now.addYear;                 // → 2025-02-28
final chained = now.addYear.addYear.addMonth; // → 2026-03-29
final future = now.addDecades(2);             // → 2044-02-29
final long = now.addCenturies(1);             // → 2124-02-29

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🧩 isSame — Compare Temporal Precision

Quickly compare two DateTime instances with precision — from year-level down to microseconds. Each method checks only the relevant granularity, making it ideal for scheduling, display logic, or grouping events.

• isSameMicrosecond(DateTime)
• isSameMillisecond(DateTime)
• isSameSecond(DateTime)
• isSameMinute(DateTime)
• isSameHour(DateTime)
• isSameDay(DateTime)
• isSameMonth(DateTime)
• isSameYear(DateTime)
• isSameDecade(DateTime) (10-year spans)
• isSameCentury(DateTime) (100-year spans)

Each method returns true if the current DateTime matches the given one at that specific resolution.

🧪 Example

final a = DateTime(2024, 4, 20, 10, 15);
final b = DateTime(2024, 4, 20, 10, 45);

a.isSameDay(b);     // → true
a.isSameHour(b);    // → true
a.isSameMinute(b);  // → false

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🧱 startOf / endOf — DateTime Boundaries

Get the exact start or end of any time unit — minute, hour, day, week, month, or year. These helpers return a new DateTime aligned to the boundary, ideal for filtering, grouping, or time range logic.

• startOfMillisecond / endOfMillisecond
• startOfSecond / endOfSecond
• startOfMinute / endOfMinute
• startOfHour / endOfHour
• startOfDay / endOfDay
• startOfWeek / endOfWeek (Monday → Sunday)
• startOfMonth / endOfMonth
• startOfYear / endOfYear
• startOfDecade / endOfDecade (10-year spans)
• startOfCentury / endOfCentury (100-year spans)

Each result is a fresh DateTime at the zero point of the boundary (or start of the next one, for endOf...).

🧪 Example

final now = DateTime(2024, 4, 20, 15, 45, 12);

now.startOfDay;   // → 2024-04-20 00:00:00
now.endOfDay;     // → 2024-04-21 00:00:00
now.startOfWeek;  // → 2024-04-15 00:00:00 (Monday)
now.endOfMonth;   // → 2024-05-01 00:00:00

These methods respect the original timezone (local or UTC).

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🐸 leap — Leap Year, Month, and Day Detection

Easily check if a DateTime falls in a leap year, on a leap month (February in a leap year), or on the rarest of all — leap day itself (Feb 29).

• isLeapYear — true if the year has 366 days
• isLeapMonth — true if it’s February in a leap year
• isLeapDay — true if it’s exactly February 29

🧪 Example

final date = DateTime(2024, 2, 29);
final dateNotDay = DateTime(2024, 2, 28);

date.isLeapYear;      // → true
date.isLeapMonth;     // → true
date.isLeapDay;       // → true
dateNotDay.isLeapDay; // → false

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📅 yesterday / tomorrow — Relative Day Helpers

Convenient shortcuts to get yesterday, tomorrow, and their weekday numbers — always aligned to the start of the day.

• yesterday — Start of the previous day
• tomorrow — Start of the next day
• previousWeekday — Weekday number of yesterday (1 = Monday, 7 = Sunday)
• nextWeekday — Weekday number of tomorrow

Perfect for logic around schedules, shifts, events, or time-based UI highlights.

🧪 Example

final now = DateTime(2024, 4, 20, 13, 45); // Saturday

now.yesterday;         // → 2024-04-19 00:00:00
now.tomorrow;          // → 2024-04-21 00:00:00
now.previousWeekday;   // → 5 (Friday)
now.nextWeekday;       // → 7 (Sunday)

All results respect the original time zone (local or UTC).

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➕ add — Add Time Units to a Duration

Easily extend a Duration by any time unit — from microseconds to centuries — using intuitive, chainable methods. Supports both numeric arguments and single-unit getters for clear, readable code.

• addMicroseconds(int) / addMicrosecond
• addMilliseconds(int) / addMillisecond
• addSeconds(int) / addSecond
• addMinutes(int) / addMinute
• addHours(int) / addHour
• addDays(int) / addDay
• addWeeks(int) / addWeek (7-day spans)
• addMonths(int) / addMonth (Approximation of 30-day months)
• addYears(int) / addYear (Approximation of 365-day years)
• addDecades(int) / addDecade (3650-day spans)
• addCenturies(int) / addCentury (36500-day spans)

All methods return a new Duration without modifying the original instance.

🧪 Example

final duration = Duration(hours: 1);
final extended = duration.addMinutes(30);     // → 1h 30m
final chained = duration.addDay.addHour;      // → 1d 2h
final future = duration.addDecades(1);        // → 3650d + 1h

⚠️ Note on accuracy:
The addMonths, addYears, addDecades, and addCenturies methods on Duration use fixed approximations
(30 days per month, 365 days per year, etc.). These are suitable for rough estimates, timers, or analytics —
but not for calendar-accurate date math.

✅ For precise handling of leap years, month lengths, and date rollovers, use the equivalent methods on DateTime instead.

⤴️ Back -> Table of Contents

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🧮 in — Convert Duration to Whole Units

Convert a Duration into whole, integer-based time units — perfect for calculations, comparisons, or formatting where only full units matter. These getters are safe, clear, and consistent with calendar approximations.

• inWeeks — Full 7-day weeks
• inMonths — Full 30-day months
• inYears — Full 365-day years
• inDecades — Full 10-year spans
• inCenturies — Full 100-year spans

All values are calculated using integer division and return only whole units.

final d = Duration(days: 750);
d.inYears;      // → 2
d.inMonths;     // → 25

⚠️ Note on accuracy:
The addMonths, addYears, addDecades, and addCenturies methods on Duration use fixed approximations
(30 days per month, 365 days per year, etc.). These are suitable for rough estimates, timers, or analytics —
but not for calendar-accurate date math.

✅ For precise handling of leap years, month lengths, and date rollovers, use the equivalent methods on DateTime instead.

⤴️ Back -> Table of Contents

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🧩 only — Break Down Duration by Remaining Units

Decompose a Duration into its leftover parts, excluding higher units. Ideal for time formatting (e.g. 1h 23m 45s) or visual breakdowns.

• onlyMicroseconds — Microseconds (excluding full milliseconds)
• onlyMilliseconds — Milliseconds (excluding full seconds)
• onlySeconds — Seconds (excluding full minutes)
• onlyMinutes — Minutes (excluding full hours)
• onlyHours — Hours (excluding full days)
• onlyDays — Total full days

These getters let you reconstruct any Duration piece by piece.

final duration = Duration(days: 1, hours: 2, minutes: 45, seconds: 30);

final days = duration.onlyDays;
final hours = duration.onlyHours;
final minutes = duration.onlyMinutes;
final seconds = duration.onlySeconds;

print('$days days, $hours hours, $minutes minutes, $seconds seconds');
// → 1 days, 2 hours, 45 minutes, 30 seconds

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🧼 without — Remove Full Units from a Duration

Strip away full units from a Duration, leaving only the remainder. Useful when you want the leftover time within a day, hour, minute, or second — like isolating time of day or breaking durations into parts.

• withoutDays — Removes full days, keeps hours/minutes/etc.
• withoutHours — Removes full hours, keeps minutes/seconds/etc.
• withoutMinutes — Removes full minutes, keeps seconds/milliseconds/etc.
• withoutSeconds — Removes full seconds, keeps milliseconds/microseconds
• withoutMilliseconds — Removes full milliseconds, keeps microseconds

Each method returns a new Duration with the higher units removed.

🧪 Example

final d = Duration(hours: 2, minutes: 45, seconds: 30);
final remainder = d.withoutHours; // → 0:45:30.000000

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🏗️ factories — Create Durations from Any Unit

A unified way to construct Duration instances from any time unit — including long spans like months, years, decades, and centuries. Provides both numeric constructors and ready-to-use constants.

• microseconds(int), milliseconds(int), seconds(int)
• minutes(int), hours(int), days(int)
• weeks(int), months(int), years(int)
• decades(int), centuries(int)
• Predefined constants: microsecond, millisecond, second, minute, hour, day, week, month, year, decade, century

These are calendar-aligned approximations:

• 1 week = 7 days
• 1 month = 30 days
• 1 year = 365 days
• 1 decade = 3650 days
• 1 century = 36500 days

🧪 Example

final workout = DurationFrom.minutes(45);
final breakTime = DurationFrom.week; // constant: 7 days
final future = workout + DurationFrom.years(2);

⚠️ Note on accuracy:
The addMonths, addYears, addDecades, and addCenturies methods on Duration use fixed approximations
(30 days per month, 365 days per year, etc.). These are suitable for rough estimates, timers, or analytics —
but not for calendar-accurate date math.

✅ For precise handling of leap years, month lengths, and date rollovers, use the equivalent methods on DateTime instead.

⤴️ Back -> Table of Contents

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🔗 License MIT © Jozz

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