common: implement jdnTzolkin

This commit is contained in:
Quantum 2025-06-17 22:04:14 -04:00
parent 273e8b1d6a
commit d0d2ebcac5

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@ -58,3 +58,10 @@ export function tzolkinName(name: TzolkinName): string {
export function formatTzolkin(tzolkin: Tzolkin): string { export function formatTzolkin(tzolkin: Tzolkin): string {
return `${tzolkin.number} ${tzolkinName(tzolkin.name)}`; return `${tzolkin.number} ${tzolkinName(tzolkin.name)}`;
} }
export function jdnTzolkin(jdn: number): Tzolkin {
return {
number: ((jdn % 13 + 18) % 13 + 1) as TzolkinNumber,
name: (jdn % 20 + 36) % 20,
};
}