The Ethiopian Holiday System in Kenat

The kenat library has a comprehensive system for calculating and categorizing the many holidays observed in Ethiopia. This system understands the nuances between fixed holidays, movable Christian feasts, and movable Islamic holidays, and provides a powerful tagging system for filtering them.

Holiday Types

Kenat processes three distinct types of holidays to ensure accurate date reporting.

1. Fixed Holidays

These are holidays that occur on the same date in the Ethiopian calendar every year.

• Examples:
  • Enkutatash (New Year): Meskerem 1
  • Meskel (Finding of the True Cross): Meskerem 17
  • Gena (Ethiopian Christmas): Tahsas 29
  • Adwa Victory Day: Yekatit 23
• Implementation: These dates are stored in a fixedHolidays map within the library for direct lookup.

2. Movable Christian Holidays

These are holidays whose dates change each year. Their calculation is based on the date of Easter (Tinsaye), which is determined by the ancient Bahire Hasab computational system.

• Examples:
  • Nineveh (Fast of Nineveh)
  • Abiy Tsome (Great Lent)
  • Fasika (Easter)
• Implementation: The library first calculates the date of the Fast of Nineveh for the given year, and all other movable feasts are determined by adding a fixed number of days from that date.

3. Movable Islamic Holidays

These holidays are based on the Islamic Hijri calendar, which is a lunar calendar. Because the lunar year is shorter than the solar Ethiopian year, the dates of these holidays shift annually and can sometimes occur twice within a single Ethiopian year.

• Examples:
  • Eid al-Fitr (End of Ramadan)
  • Eid al-Adha (Feast of the Sacrifice)
  • Moulid (The Prophet’s Birthday)
• Implementation: The library calculates all possible Gregorian occurrences of a Hijri date within the span of an Ethiopian year and converts them to their Ethiopian calendar equivalents.

Filtering with HolidayTags

To make it easy to find specific types of holidays, every holiday in kenat is categorized with one or more tags. These are available in the exported HolidayTags object.

The available tags are:

• PUBLIC: A public national holiday.
• RELIGIOUS: A holiday of religious significance.
• CHRISTIAN: A Christian holiday.
• MUSLIM: A Muslim holiday.
• STATE: A state holiday commemorating a civic event.
• CULTURAL: A holiday of cultural significance.
• OTHER: Any other type of observance.

Example: Using the filter Option

You can pass a tag (string) or an array of tags to the filter option in functions like getHolidaysForYear and getHolidaysInMonth.

When you provide an array of tags, the filter returns holidays that match at least one of the tags provided (an “OR” search).

import { getHolidaysForYear, HolidayTags } from 'kenat';
 
const year = 2017; // E.C.
 
// Example 1: Get only public holidays by passing a single tag.
const publicHolidays = getHolidaysForYear(year, {
filter: HolidayTags.PUBLIC
});
 
console.log(`Found ${publicHolidays.length} public holidays in ${year} E.C.`);
// Expected: Lists all holidays tagged as 'public'.
 
 
// Example 2: Get holidays that are 'MUSLIM' OR 'STATE'.
// Pass an array of tags to the filter option.
const muslimOrStateHolidays = getHolidaysForYear(year, {
    filter: [HolidayTags.MUSLIM, HolidayTags.STATE]
});
 
console.log(`Found ${muslimOrStateHolidays.length} holidays that are either Muslim or State holidays.`);