calendaryjs-plugin-liturgical

The General Roman Calendar: Easter computus, movable feasts, seasons, ranks and colors, plus event generators.

Install

npm i calendaryjs calendaryjs-plugin-liturgical

Easter

import { computeEaster } from "calendaryjs-plugin-liturgical";

computeEaster(2025); // → Date for Easter Sunday 2025

Offset events

Define feasts relative to Easter (Ash Wednesday, Pentecost, …):

import { calendary } from "calendaryjs";
import { liturgical } from "calendaryjs-plugin-liturgical";

const cal = calendary().use(liturgical());

cal.addGroup({
  id: "movable",
  events: [
    {
      type: "offset",
      id: "pentecost",
      baseEvent: "easter",
      offsetDays: 49,
      title: "Pentecost",
    },
  ],
});

An unknown baseEvent throws rather than silently producing nothing.