EDTFSeason

Represents a season within a year (Levels 1 and 2).

Interface

interface EDTFSeason extends EDTFBase {
  type: 'Season';
  year: number;
  season: number;
  qualification?: Qualification;
}

Properties

Property	Type	Description
type	'Season'	Type discriminator
year	number	Year
season	number	Season code (21-41)
qualification	Qualification?	Uncertainty/approximation flags

Inherited from EDTFBase

Property	Type	Description
level	1 | 2	Level 1 or 2
edtf	string	Original EDTF string
precision	'month'	Always 'month' precision
min	Date	First day of the season
max	Date	Last day of the season

Season Codes

Seasons (Independent of Location) (Level 1)

Code	Season	Months
21	Spring	March - May
22	Summer	June - August
23	Autumn	September - November
24	Winter	December - February

Northern Hemisphere Seasons (Level 2)

Code	Season	Months
25	Spring (Northern Hemisphere)	March - May
26	Summer (Northern Hemisphere)	June - August
27	Autumn (Northern Hemisphere)	September - November
28	Winter (Northern Hemisphere)	December - February

Southern Hemisphere Seasons (Level 2)

Code	Season	Months
29	Spring (Southern Hemisphere)	September - November
30	Summer (Southern Hemisphere)	December - February
31	Autumn (Southern Hemisphere)	March - May
32	Winter (Southern Hemisphere)	June - August

Quarters (Level 2)

Code	Quarter	Months
33	Quarter 1	January - March
34	Quarter 2	April - June
35	Quarter 3	July - September
36	Quarter 4	October - December

Quadrimesters (Level 2)

Code	Quadrimester	Months
37	Quadrimester 1	January - April
38	Quadrimester 2	May - August
39	Quadrimester 3	September - December

Semestrals (Level 2)

Code	Semestral	Months
40	Semestral 1	January - June
41	Semestral 2	July - December

Usage

import { parse, isEDTFSeason } from '@edtf-ts/core';

const result = parse('2001-21');

if (result.success && isEDTFSeason(result.value)) {
  const season = result.value;

  console.log(season.year);    // 2001
  console.log(season.season);  // 21 (Spring)
  console.log(season.min);     // Date: 2001-03-01
  console.log(season.max);     // Date: 2001-05-31
}

Examples

// Seasons (independent of location)
parse('2001-21');  // Spring 2001
parse('2001-22');  // Summer 2001
parse('2001-23');  // Autumn 2001
parse('2001-24');  // Winter 2001

// Northern Hemisphere seasons
parse('2001-25');  // Spring (Northern Hemisphere) 2001
parse('2001-26');  // Summer (Northern Hemisphere) 2001
parse('2001-27');  // Autumn (Northern Hemisphere) 2001
parse('2001-28');  // Winter (Northern Hemisphere) 2001

// Southern Hemisphere seasons
parse('2001-29');  // Spring (Southern Hemisphere) 2001
parse('2001-30');  // Summer (Southern Hemisphere) 2001
parse('2001-31');  // Autumn (Southern Hemisphere) 2001
parse('2001-32');  // Winter (Southern Hemisphere) 2001

// Quarters
parse('2001-33');  // Quarter 1 2001
parse('2001-34');  // Quarter 2 2001
parse('2001-35');  // Quarter 3 2001
parse('2001-36');  // Quarter 4 2001

// Quadrimesters
parse('2001-37');  // Quadrimester 1 2001
parse('2001-38');  // Quadrimester 2 2001
parse('2001-39');  // Quadrimester 3 2001

// Semestrals
parse('2001-40');  // Semestral 1 2001
parse('2001-41');  // Semestral 2 2001

Qualified Seasons

Seasons can have qualifications (Level 1):

parse('2001-21?');  // Uncertain spring
parse('2001-21~');  // Approximate spring
parse('2001-21%');  // Uncertain and approximate

const result = parse('2001-21?');
if (result.success && isEDTFSeason(result.value)) {
  console.log(result.value.qualification?.uncertain);  // true
}

Type Guard

import { isEDTFSeason } from '@edtf-ts/core';

const result = parse(input);
if (result.success && isEDTFSeason(result.value)) {
  // TypeScript knows result.value is EDTFSeason
  console.log(result.value.season);
}

Formatting

import { parse, formatHuman } from '@edtf-ts/core';

const result = parse('2001-21');
if (result.success) {
  formatHuman(result.value);  // 'Spring 2001'
}