c-3po-runtime.js

import { t,  addLocale, useLocale } from 'c-3po';
import gettextParser from 'gettext-parser';
import fs from 'fs';

const locale = process.env.LOCALE; // let's desice that locale is passed through ENV

if (locale) {
    // parsing po file with gettext-parser and applying translations
    const translationObj = gettextParser.po.parse(
        fs.readFileSync(`${locale}.po`).toString()
    );
    addLocale(locale, translationObj);
    useLocale(locale);
}

const name = 'c-3po';
t`Hello ${ name }`