libyear/src/date.js

A simple measure of software dependency freshness

// TODO[engine:node@>=24]: drop @js-temporal/polyfill
import { Temporal } from "@js-temporal/polyfill";
const DAYS_IN_YEAR = 365.2425;
const parseISO = (item) => Temporal.Instant.from(item).toZonedDateTimeISO(item).toPlainDateTime();
const differenceInDays = (laterDate, earlierDate) => laterDate.since(earlierDate).days;
/**
 * Time since last version update.
 * Measure of dependency drift.
 */
export const calculateDrift = (currentVersion, latestVersion) => currentVersion && latestVersion
    ? differenceInDays(parseISO(latestVersion), parseISO(currentVersion)) /
        DAYS_IN_YEAR
    : 0;
/**
 * Time since latest version release.
 * Pulse check of dependency activity and maintenance.
 */
export const calculatePulse = (latestVersion) => latestVersion
    ? differenceInDays(Temporal.Now.plainDateTimeISO(), parseISO(latestVersion)) / DAYS_IN_YEAR
    : 0;