intl/scripts/utils/extract-calendars.js

Polyfill the ECMA-402 Intl API (except collation)

import * as glob from 'glob';
import * as path from 'path';

import {
    getParentLocale,
    hasCalendars,
    normalizeLocale,
} from './locales';

export default function extractCalendars(locales) {
    let cache = {};

    // Loads and caches the date calendars for a given `locale` because loading
    // and transforming the data is expensive.
    function getCalendars(locale) {
        let calendars = cache[locale];
        if (calendars) {
            return calendars;
        }

        if (hasCalendars(locale)) {
            calendars = cache[locale] = loadCalendars(locale);
            return calendars;
        }
    }

    // This will traverse the hierarchy for the
    // given `locale` until it finds an ancestor with date calendars.
    function findLocaleWithCalendar(locale) {
        // The "root" locale is the top level ancestor.
        if (locale === 'root') {
            return 'root';
        }

        if (hasCalendars(locale)) {
            return locale;
        }

        // When the `locale` doesn't have calendars data, we need to traverse up
        // its hierarchy to find suitable date calendars data.
        return findLocaleWithCalendar(getParentLocale(locale));
    }

    return locales.reduce((calendars, locale) => {
        locale = normalizeLocale(locale);

        // Walk the `locale`'s hierarchy to look for suitable ancestor with the
        // date calendars. If no ancestor is found, the given
        // `locale` will be returned.
        let resolvedLocale = findLocaleWithCalendar(locale);

        // Add an entry for the `locale`, which might be an ancestor. If the
        // locale doesn't have relative fields, then we fallback to the "root"
        // locale's fields.
        calendars[locale] = {
            calendars: getCalendars(resolvedLocale),
        };

        return calendars;
    }, {});
}

function loadCalendars(locale) {
    // all NPM packages providing calendars specific data
    let pkgs = [
        "cldr-dates-full",
        "cldr-cal-buddhist-full",
        "cldr-cal-chinese-full",
        "cldr-cal-coptic-full",
        "cldr-cal-dangi-full",
        "cldr-cal-ethiopic-full",
        "cldr-cal-hebrew-full",
        "cldr-cal-indian-full",
        "cldr-cal-islamic-full",
        "cldr-cal-japanese-full",
        "cldr-cal-persian-full",
        "cldr-cal-roc-full",
    ];
    // walking all packages, selecting calendar files, then
    // reading the content of each calendar, and concatenating the set
    return pkgs.reduce((calendars, pkgName) => {
        let dir = path.resolve(path.dirname(require.resolve(pkgName + '/package.json')), 'main', locale);
        let filenames = glob.sync("ca-*.json", {
                cwd: dir,
            });
        return filenames.reduce((calendars, filename) => {
            return Object.assign(calendars, require(path.join(dir, filename)).main[locale].dates.calendars);
        }, calendars);
    }, {});
}