isSame()

Checks if this date is the same as another date, optionally at a specific granularity.

Syntax

.isSame(other: FduInstance, unit?: UnitType): boolean

Parameters

other: FduInstance - Date to compare with
unit?: UnitType - Optional unit for granularity comparison

Returns

boolean - True if dates are the same (at the specified granularity)

Examples

Exact Comparison

Without a unit, compares exact timestamps:

import { fdu } from '@pyyupsk/fdu';

const date1 = fdu('2024-01-15T10:30:00');
const date2 = fdu('2024-01-15T10:30:00');
const date3 = fdu('2024-01-15T14:45:00');

date1.isSame(date2);  // true (exact same time)
date1.isSame(date3);  // false (different times)

Granular Comparison

Compare at specific units of time:

const date1 = fdu('2024-01-15T10:30:00');
const date2 = fdu('2024-01-15T14:45:00');

// Same day, different times
date1.isSame(date2, 'day');     // true
date1.isSame(date2, 'month');   // true
date1.isSame(date2, 'year');    // true
date1.isSame(date2, 'hour');    // false
date1.isSame(date2, 'minute');  // false

Different Days

const date1 = fdu('2024-01-15T10:30:00');
const date2 = fdu('2024-01-16T10:30:00');

date1.isSame(date2, 'day');     // false
date1.isSame(date2, 'month');   // true
date1.isSame(date2, 'year');    // true

Different Months

const date1 = fdu('2024-01-15');
const date2 = fdu('2024-02-15');

date1.isSame(date2, 'month');   // false
date1.isSame(date2, 'year');    // true

Different Years

const date1 = fdu('2024-01-15');
const date2 = fdu('2025-01-15');

date1.isSame(date2, 'year');    // false

Supported Units

year / y - Same calendar year
month / M - Same calendar month and year
day / d - Same calendar day
hour / h - Same hour
minute / m - Same minute
second / s - Same second

Common Patterns

Check if dates are on the same day

const date1 = fdu('2024-01-15T09:00:00');
const date2 = fdu('2024-01-15T17:00:00');

if (date1.isSame(date2, 'day')) {
  console.log('These events are on the same day');
}

Check if today

function isToday(date: FduInstance): boolean {
  return date.isSame(fdu(), 'day');
}

const someDate = fdu('2024-01-15');
isToday(someDate);  // true if today is Jan 15, 2024

Group by month

const dates = [
  fdu('2024-01-05'),
  fdu('2024-01-15'),
  fdu('2024-02-10'),
  fdu('2024-02-20')
];

const januaryDates = dates.filter(d =>
  d.isSame(fdu('2024-01-01'), 'month')
);
// [2024-01-05, 2024-01-15]

Check if same week

const date1 = fdu('2024-01-15');  // Monday
const date2 = fdu('2024-01-18');  // Thursday

// Note: isSame doesn't have 'week' unit, use alternative:
const startOfWeek1 = date1.subtract(date1.day(), 'day');
const startOfWeek2 = date2.subtract(date2.day(), 'day');

startOfWeek1.isSame(startOfWeek2, 'day');  // true

Birthday check

function isBirthday(birthdate: FduInstance): boolean {
  const today = fdu();
  return birthdate.month() === today.month() &&
         birthdate.date() === today.date();
}

const birthday = fdu('1990-05-15');
isBirthday(birthday);  // true if today is May 15

Same time of day check

const time1 = fdu('2024-01-15T14:30:00');
const time2 = fdu('2024-02-20T14:30:00');

const sameHour = time1.isSame(time2, 'hour') &&
                 time1.minute() === time2.minute();
// true (both at 14:30)

Filter events by year

const events = [
  { date: fdu('2023-05-15'), name: 'Event A' },
  { date: fdu('2024-01-20'), name: 'Event B' },
  { date: fdu('2024-06-10'), name: 'Event C' }
];

const year2024 = fdu('2024-01-01');
const events2024 = events.filter(e =>
  e.date.isSame(year2024, 'year')
);
// [Event B, Event C]

@pyyupsk/fdu