Bangla Calendar Integration

banglaPlugin

📦 Import & Usage

tip

To use the Bangla Plugin, import it and register it with Chronos:

import { Chronos, chronos } from 'nhb-toolbox';
import { banglaPlugin } from 'nhb-toolbox/plugins/banglaPlugin';

// Register the plugin globally
Chronos.use(banglaPlugin);
// or
chronos.use(banglaPlugin);
// or
Chronos.register(banglaPlugin);
// or
chronos.register(banglaPlugin);

// Now use Bangla calendar methods
const c = new Chronos('2023-04-14');
const banglaDate = c.toBangla(); // Get complete Bangla date object

---

📋 Overview

The banglaPlugin adds comprehensive Bengali calendar functionality to Chronos, enabling:

• Conversion between Gregorian and Bengali calendar dates
• Bengali date formatting with customizable tokens
• Access to Bengali year, month, day names, and seasons
• Support for two calendar variants: 'revised-2019' (default) and 'revised-1966'
• Multi-locale output (Bangla digits/names or Latin equivalents)

---

🎯 Methods Added by This Plugin

Method	Description	Returns
toBangla()	Converts to complete Bangla date object	BanglaDateObject
formatBangla()	Formats date using Bengali tokens	string
getBanglaYear()	Gets Bengali year	string or number
getBanglaMonth()	Gets Bengali month	string or number
getBanglaDay()	Gets Bengali day of month	string or number
getBanglaDayName()	Gets Bengali weekday name	string
getBanglaMonthName()	Gets Bengali month name	string
getBanglaSeasonName()	Gets Bengali season name	string
configureBanglaCalendar()	Sets default calendar variant globally	void

---

📚 API Reference

toBangla()

Converts the current date to a complete Bangla calendar date object.

Signature

toBangla<Locale extends $BnEn = 'bn'>(
  options?: BanglaDateOptions<Locale>
): BanglaDateObject<Locale>

Parameters

• options: Optional configuration including:
  • locale: 'bn' (default) for Bengali output, 'en' for English/Latin output
  • variant: Calendar variant ('revised-2019' or 'revised-1966')

Return Value

Complete Bangla date object containing:

{
  year: string | number,      // Bengali year
  month: string | number,     // Bengali month (1-12)
  date: string | number,      // Bengali day of month (1-31)
  monthName: string,          // Bengali month name
  dayName: string,            // Bengali weekday name
  seasonName: string,         // Bengali season name
  isLeapYear: boolean         // Whether it's a leap year
}

Examples

const chronos = new Chronos('2023-04-14');
const banglaDate = chronos.toBangla();
// Returns: {
//   year: '১৪৩০',
//   month: '১',
//   date: '১',
//   monthName: 'বৈশাখ',
//   dayName: 'শুক্রবার',
//   seasonName: 'গ্রীষ্ম',
//   isLeapYear: false
// }

const banglaDateEn = chronos.toBangla({ locale: 'en' });
// Returns: {
//   year: 1430,
//   month: 1,
//   date: 1,
//   monthName: 'Boishakh',
//   dayName: 'Shukrobar (Friday)',
//   seasonName: 'Grisma (Summer)',
//   isLeapYear: false
// }

Remarks

• Uses the default calendar variant ('revised-2019') unless specified
• The locale determines output format (Bangla vs Latin)
• Year 0 corresponds to 593 CE in the Gregorian calendar

---

formatBangla()

Formats the current date as a Bangla calendar date string using customizable tokens.

Signature

formatBangla(format?: StrictFormat, options?: BnCalendarConfig): string

Parameters

• format: Format string using tokens (default: 'ddd, DD mmmm (SS), YYYY বঙ্গাব্দ - hh:mm:ss (A)')
• options: Calendar configuration with variant property

Return Value

Formatted Bangla date string according to the specified format.

Format Tokens

Token	Description	Example
YYYY	Full year (Bangla digits)	১৪৩০
YY	Last 2 digits of year	৩০
M or MM	Month (non-padded/padded)	১ or ০১
mmm	Short month name	বৈ
mmmm	Full month name	বৈশাখ
D or DD	Day of month (non-padded/padded)	১ or ০১
Do	Cardinal day (same as D)	১
d	Short weekday	র
dd	Weekday without 'বার'	রবি
ddd	Full weekday	রবিবার
H or HH	24-hour (non-padded/padded)	২ or ০২
h or hh	12-hour (non-padded/padded)	৭ or ০৭
m or mm	Minute (non-padded/padded)	৯ or ০৯
s or ss	Second (non-padded/padded)	৫ or ০৫
ms or mss	Millisecond (non-padded/padded)	২৩ or ০২৩
a or A	AM/PM indicator	পূর্বাহ্ণ/অপরাহ্ণ
Z or ZZ	UTC offset	+০৬:০০
S	Season name	গ্রীষ্ম
SS	Season with 'কাল' suffix	গ্রীষ্মকাল

Escaping Text

To output raw text (not interpreted as a token), wrap it in square brackets:

• [আজ] ddd → আজ রবিবার
• [year ]YYYY → year ২০২৫

Examples

const chronos = new Chronos('2023-04-14 14:30:00');

chronos.formatBangla();
// Returns: 'শুক্রবার, বৈশাখ ০১ (গ্রীষ্মকাল), ১৪৩০ বঙ্গাব্দ - ০২:৩০:০০ (অপরাহ্ণ)'

chronos.formatBangla('YYYY-MM-DD');
// Returns: '১৪৩০-০১-০১'

chronos.formatBangla('mmmm DD, YYYY');
// Returns: 'বৈশাখ ০১, ১৪৩০'

chronos.formatBangla('hh:mm:ss A');
// Returns: '০২:৩০:০০ অপরাহ্ণ'

chronos.formatBangla('[আজ] ddd, DD mmmm');
// Returns: 'আজ শুক্রবার, ০১ বৈশাখ'

---

getBanglaYear()

Gets the Bangla calendar year for the current date.

Signature

getBanglaYear<Locale extends $BnEn = 'bn'>(locale?: Locale): $BanglaYear<Locale>

Parameters

• locale: 'bn' (default) for Bangla digits, 'en' for Latin digits

Return Value

Bangla year in the specified locale format.

Examples

const chronos = new Chronos('2023-04-14');
chronos.getBanglaYear(); // Returns: '১৪৩০'
chronos.getBanglaYear('en'); // Returns: 1430

Remarks

• The Bangla year starts on April 14th in the Gregorian calendar
• Year 0 corresponds to 593 CE

---

getBanglaMonth()

Gets the Bangla calendar month for the current date.

Signature

getBanglaMonth<Locale extends $BnEn = 'bn'>(
  options?: BanglaDateOptions<Locale>
): $BanglaMonth<Locale>

Parameters

• options: Optional configuration with locale and variant

Return Value

Bangla month (1-12) in the specified locale format.

Examples

const chronos = new Chronos('2023-04-14');
chronos.getBanglaMonth(); // Returns: '১' (বৈশাখ)
chronos.getBanglaMonth({ locale: 'en' }); // Returns: 1
chronos.getBanglaMonth({ variant: 'revised-1966' }); // Uses 1966 variant

Remarks

• Month 1 corresponds to বৈশাখ (mid-April to mid-May)
• Results may vary between calendar variants near month boundaries

---

getBanglaDay()

Gets the Bangla calendar day of the month for the current date.

Signature

getBanglaDay<Locale extends $BnEn = 'bn'>(
  options?: BanglaDateOptions<Locale>
): $BanglaMonthDate<Locale>

Parameters

• options: Optional configuration with locale and variant

Return Value

Bangla day of month (1-31) in the specified locale format.

Examples

const chronos = new Chronos('2023-04-14');
chronos.getBanglaDay(); // Returns: '১'
chronos.getBanglaDay({ locale: 'en' }); // Returns: 1
chronos.getBanglaDay({ variant: 'revised-1966' }); // Uses 1966 variant

Remarks

• The day number is 1-based (১ = first day of the month)
• Different variants may have different month lengths for leap years

---

getBanglaDayName()

Gets the Bangla name of the weekday for the current date.

Signature

getBanglaDayName<Locale extends $BnEn = 'bn'>(locale?: Locale): BanglaDayName<Locale>

Parameters

• locale: 'bn' (default) for Bengali, 'en' for English

Return Value

Name of the weekday in the specified locale.

Examples

const chronos = new Chronos('2023-04-14'); // Friday
chronos.getBanglaDayName(); // Returns: 'শুক্রবার'
chronos.getBanglaDayName('en'); // Returns: 'Shukrobar (Friday)'

Remarks

• Weekday names follow standard Bengali naming convention ending with 'বার'
• English names include transliteration and standard English name

---

getBanglaMonthName()

Gets the Bangla name of the month for the current date.

Signature

getBanglaMonthName<Locale extends $BnEn = 'bn'>(
  options?: BanglaDateOptions<Locale>
): BanglaMonthName<Locale>

Parameters

• options: Optional configuration with locale and variant

Return Value

Name of the month in the specified locale.

Examples

const chronos = new Chronos('2023-04-14');
chronos.getBanglaMonthName(); // Returns: 'বৈশাখ'
chronos.getBanglaMonthName({ locale: 'en' }); // Returns: 'Boishakh'
chronos.getBanglaMonthName({ variant: 'revised-1966' }); // Uses 1966 variant

Remarks

• Month names follow traditional Bengali naming conventions
• English names are transliterations of Bengali names

---

getBanglaSeasonName()

Gets the Bangla season name for the current date.

Signature

getBanglaSeasonName<Locale extends $BnEn = 'bn'>(
  options?: BanglaDateOptions<Locale>
): BanglaSeasonName<Locale>

Parameters

• options: Optional configuration with locale and variant

Return Value

Name of the season in the specified locale.

Examples

const chronos = new Chronos('2023-04-14');
chronos.getBanglaSeasonName(); // Returns: 'গ্রীষ্ম'
chronos.getBanglaSeasonName({ locale: 'en' }); // Returns: 'Grisma (Summer)'

Bengali Seasons (ঋতু)

Season (Bangla)	English	Period
গ্রীষ্ম	Grisma (Summer)	Mid-April to Mid-June
বর্ষা	Barsa (Monsoon)	Mid-June to Mid-August
শরৎ	Sarat (Autumn)	Mid-August to Mid-October
হেমন্ত	Hemanta (Late Autumn)	Mid-October to Mid-December
শীত	Shhit (Winter)	Mid-December to Mid-February
বসন্ত	Basanta (Spring)	Mid-February to Mid-April

---

configureBanglaCalendar()

Sets the default Bangla calendar variant globally for all Chronos instances.

Signature

configureBanglaCalendar(options: BnCalendarConfig): void

Parameters

• options: Configuration with variant property ('revised-2019' or 'revised-1966')

Behavior

• Sets the global default variant for all Bangla-related methods
• Affects all existing and future Chronos instances
• Can be overridden per-call using the variant option in individual methods

Examples

const c1 = new Chronos();
const c2 = new Chronos();

// Default is 'revised-2019'
c1.getBanglaMonth(); // uses 'revised-2019'

// Set global default to 1966 variant
c1.configureBanglaCalendar({ variant: 'revised-1966' });

c1.getBanglaMonth(); // now uses 'revised-1966'
c2.getBanglaMonth(); // also uses 'revised-1966'

// Per-call override still works
c1.getBanglaMonth({ variant: 'revised-2019' }); // uses 'revised-2019' for this call only

Important Notes

• This method does not modify the instance, only sets global configuration
• If never called, default is 'revised-2019'
• Valid variants: 'revised-1966' and 'revised-2019'

---

🗂️ Type Definitions

BanglaDateObject

type BanglaDateObject<Locale extends $BnEn = 'bn'> = {
  year: $BanglaYear<Locale>;          // Bengali year
  month: $BanglaMonth<Locale>;        // Bengali month (1-12)
  date: $BanglaMonthDate<Locale>;     // Bengali day of month (1-31)
  dayName: BanglaDayName<Locale>;     // Bengali weekday name
  monthName: BanglaMonthName<Locale>; // Bengali month name
  seasonName: BanglaSeasonName<Locale>; // Bengali season name
  isLeapYear: boolean;                // Leap year status
};

BanglaDateOptions

interface BanglaDateOptions<Locale extends $BnEn> extends BnCalendarConfig {
  locale?: Locale | $BnEn;  // 'bn' or 'en'
}

interface BnCalendarConfig {
  variant?: BnCalendarVariant;  // 'revised-2019' or 'revised-1966'
}

Calendar Variants

type BnCalendarVariant = 'revised-2019' | 'revised-1966';

---

💡 Complete Example

import { Chronos } from 'nhb-toolbox';
import { banglaPlugin } from 'nhb-toolbox/plugins/banglaPlugin';

// Register plugin
Chronos.use(banglaPlugin);

// Create a date (April 14, 2023 = 1st Boishakh, 1430)
const chronos = new Chronos('2023-04-14 14:30:00');

// Get complete Bangla date object
const banglaDate = chronos.toBangla();
console.log(banglaDate);
// {
//   year: '১৪৩০',
//   month: '১',
//   date: '১',
//   monthName: 'বৈশাখ',
//   dayName: 'শুক্রবার',
//   seasonName: 'গ্রীষ্ম',
//   isLeapYear: false
// }

// Format in Bengali
console.log(chronos.formatBangla());
// শুক্রবার, বৈশাখ ০১ (গ্রীষ্মকাল), ১৪৩০ বঙ্গাব্দ - ০২:৩০:০০ (অপরাহ্ণ)

// Format with custom pattern
console.log(chronos.formatBangla('DD mmmm, YYYY'));
// ০১ বৈশাখ, ১৪৩০

// Get individual components
console.log(chronos.getBanglaYear()); // '১৪৩০'
console.log(chronos.getBanglaMonthName()); // 'বৈশাখ'
console.log(chronos.getBanglaSeasonName()); // 'গ্রীষ্ম'
console.log(chronos.getBanglaDayName('en')); // 'Shukrobar (Friday)'

// Switch to 1966 variant
chronos.configureBanglaCalendar({ variant: 'revised-1966' });
console.log(chronos.getBanglaMonth({ variant: 'revised-1966' })); // '১' (using 1966 variant)

---

See Also

• Dedicated class: BanglaCalendar for Bangla date manipulation without using Chronos