moment-js-datefmt-per-country.js

const moment = require('moment');
const CountryLanguage = require('country-language');
const glob = require('glob-promise');
const path = require('path');
const Promise = require('bluebird');

console.log('resolved=', require.resolve('moment'));

const data = {};


const loadLocale = l => {
    const locale = path.parse(l).name;
    matchData = locale.match(/^([a-z]{2})(?:-([a-z]{2}))?$/);
    if (!matchData) {
        return Promise.resolve();
    }
    const lang = matchData[1];

    return new Promise((resolve, reject) => {
        const withCountry = (country, priority) => {
            // console.log('l=', locale);
            moment.locale(locale);
            const localeData = moment.localeData()
            //console.log('localeData.longDateFormat()=', localeData.longDateFormat());
            if (!data[country] || data[country].priority > priority) {
                data[country] = {
                    dateFormat: localeData.longDateFormat('L'),
                    priority,
                };
            }
        };

        if (matchData[2]) {
            withCountry(matchData[2].toUpperCase(), -1);
            resolve();
        } else {
            CountryLanguage.getLanguageCountries(lang, (err, countries) => {
                if (err) {
                    console.error(err);
                } else {
                    Promise.map(countries, (country, index) => withCountry(country.code_2, index));
                }
                resolve();
            });
        }
    });
};

glob.promise(path.join(path.dirname(require.resolve('moment')), 'locale/*.js'))
    .then(allLocaleFiles => Promise.map(allLocaleFiles, loadLocale))
    .then(() => {
        const allCountries = Object.keys(data);
        allCountries.sort();
        console.log('export default {')
        allCountries.forEach(country => {
            console.log(`  ${country}: ${JSON.stringify(data[country].dateFormat)},`);
        });
        console.log('};');
    })
;