ThirteenMonthsDate

Description

ThirteenMonthsDate is a JavaScript class that implements a 13-month calendar system. This calendar system divides the year into 13 months of 28 days each, with an additional "Intercalary Day" added to leap years. The class provides functionality similar to the native JavaScript Date object, but adjusted for the 13-month calendar system (International Fixed Calendar).

Features

• Implements a 13-month calendar system
• Handles leap years with an Intercalary Day
• Provides methods similar to the native JavaScript Date object
• Supports both local and UTC time operations

Installation

Use the package manager npm to install thirteen-months-date.

npm install thirteen-months-date

Usage

Creating a ThirteenMonthsDate Object

You can create a ThirteenMonthsDate object in several ways:

// Current date and time
const date1 = new ThirteenMonthsDate();

// From a timestamp
const date2 = new ThirteenMonthsDate(1632145200000);

// From a (12 months 'Gregorian') date(time) string 
const date3 = new ThirteenMonthsDate("2023-12-31");

// From (12 months 'Gregorian') year, month, day, hour, minute, second, millisecond
const date4 = new ThirteenMonthsDate(2023, 5, 15, 12, 30, 0, 0);

Methods

The ThirteenMonthsDate class provides methods similar to the native Date object, including:

• getDate(), getUTCDate()
• getDay(), getUTCDay()
• getFullYear(), getUTCFullYear()
• getHours(), getUTCHours()
• getMilliseconds(), getUTCMilliseconds()
• getMinutes(), getUTCMinutes()
• getMonth(), getUTCMonth()
• getSeconds(), getUTCSeconds()
• getTime(), getTimezoneOffset(), getYear()
• setDate(), setFullYear(), setHours(), setMilliseconds(), setMinutes(), setMonth(), setSeconds(), setTime(), setYear()

Additionally, it provides some unique methods:

• getMonthName(), getUTCMonthName(): Get the name of the month
• isIntercalaryDay(), isUTCIntercalaryDay(): Check if the date is an Intercalary Day
• getGregorianDateString(), getGregorianUTCDateString(): Get the DateString in the 12 months 'Gregorian' format

Formatting Methods

The class includes various methods for formatting the date:

• toDateString()
• toISOString()
• toLocaleDateString()
• toLocaleString()
• toLocaleTimeString()
• toString()
• toTimeString()
• toUTCString()

Static Methods

• ThirteenMonthsDate.now(): Returns the current timestamp

Examples

import ThirteenMonthsDate from 'thirteen-months-date';

let date = new ThirteenMonthsDate(2023, 5, 16);

console.log('Local Gregorian DateString:', date.getGregorianDateString());
// Output: Local Gregorian DateString: Fri Jun 16 2023 00:00:00 GMT+0200 (Central European Summer Time)

console.log('UTC Gregorian DateString:', date.getGregorianUTCDateString());
// Output: UTC Gregorian DateString: Thu, 15 Jun 2023 22:00:00 GMT

console.log('Local Date:', date.getDate());
// Output: Local Date: 27

console.log('UTC Date:', date.getUTCDate());
// Output: UTC Date: 26

console.log('Local Month:', date.getMonth(), date.getMonthName());
// Output: Local Month: 5 June

console.log('UTC Month:', date.getUTCMonth(), date.monthNames[date.getUTCMonth()]);
// Output: UTC Month: 5 June

console.log('ToString:', date.toString());
// Output: ToString: Fri Jun 27 2023 00:00:00 GMT+0200 (Central European Summer Time)

console.log('ToUTCString:', date.toUTCString());
// Output: ToUTCString: Thu, 26 Jun 2023 22:00:00 GMT


date = new ThirteenMonthsDate("2023-12-31:00:30");

console.log('Local Gregorian DateString:', date.getGregorianDateString());
// Output: Local Gregorian DateString: Sun Dec 31 2023 00:30:00 GMT+0100 (Central European Standard Time)

console.log('UTC Gregorian DateString:', date.getGregorianUTCDateString());
// Output: UTC Gregorian DateString: Sat, 30 Dec 2023 23:30:00 GMT

console.log('Local Date:', date.getDate());
// Output: Local Date: 1

console.log('UTC Date:', date.getUTCDate());
// Output: UTC Date: 28

console.log('Local Month:', date.getMonth(), date.getMonthName());
// Output: Local Month: 13 Intercalary

console.log('UTC Month:', date.getUTCMonth(), date.monthNames[date.getUTCMonth()]);
// Output: UTC Month: 12 Undecember

console.log('ToString:', date.toString());
// Output: ToString: Sun Int 1 2023 00:30:00 GMT+0100 (Central European Standard Time)

console.log('ToUTCString:', date.toUTCString());
// Output: ToUTCString: Sat, 28 Und 2023 23:30:00 GMT

Note

This implementation assumes that the Intercalary Day is added as the 169th day of a leap year (June 18th in the Gregorian calendar). The behavior of this class may differ from standard calendar implementations, especially around leap years and date calculations.

For more information about the theory behind this calendar, see this Wikipedia page