@liha-labs/holiday

日本の祝日を扱う ESM ライブラリです。

• 祝日判定は公式データベース準拠（計算ロジックなし）
• holidayName() は string | null
• getHoliday() / list*() は weekday 付きの詳細を返却

Install

pnpm add @liha-labs/holiday

Exports

• @liha-labs/holiday
• @liha-labs/holiday/full

default export はありません。

Main Types

export type Holiday = { date: "YYYY-MM-DD"; name: string };
export type Weekday = 0 | 1 | 2 | 3 | 4 | 5 | 6; // 0=Sun ... 6=Sat
export type HolidayDetail = Holiday & { weekday: Weekday };

export type ClientOptions = {
  remoteBaseUrl?: string;
  fetch?: typeof globalThis.fetch;
  cache?: "memory" | "none";
};

API

holidayName(input: Date | string): Promise<string | null>
isHoliday(input: Date | string): Promise<boolean>
getHoliday(input: Date | string): Promise<HolidayDetail | null>

listYear(year: number): Promise<HolidayDetail[]>
listMonth(ym: `${number}-${string}`): Promise<HolidayDetail[]>
listRange(start: Date | string, end: Date | string): Promise<HolidayDetail[]>
listAll(): Promise<HolidayDetail[]>

createClient(options?: ClientOptions): HolidayClient
info(): Info

Basic Usage

import {
  createClient,
  getHoliday,
  holidayName,
  isHoliday,
  listMonth,
  listRange,
  listYear,
  info
} from "@liha-labs/holiday";

await holidayName("2026-01-01");
// => "元日"

await isHoliday("2026-01-02");
// => false

await getHoliday("2026-01-01");
// => { date: "2026-01-01", name: "元日", weekday: 4 }

await listYear(2026);
await listMonth("2026-01");
await listRange("2026-01-01", "2026-12-31");

const meta = info();

const client = createClient({ cache: "memory" });
await client.listYear(2035);

Full Entry Usage

import { createClient, listAll, listYear } from "@liha-labs/holiday/full";

await listYear(2026);
await listAll();

const fullClient = createClient();
await fullClient.getHoliday("2026-01-01");

Input Rules

• Date はローカル日付として getFullYear()/getMonth()/getDate() で正規化
• 文字列は YYYY-MM-DD のみ許可
• listMonth は YYYY-MM のみ許可
• 不正日付はエラー
• weekday はランタイムで new Date(y, m - 1, d).getDay() から算出