learnGitBranching-mirror/scripts/generateIntlStrings.js

/**
 * Generates src/js/intl/generated/<locale>.js + loaders.js.
 *
 * src/js/intl/strings.js holds every locale in one object (~270 KB). The app
 * only needs the active locale, plus en_US as a synchronous fallback, so we
 * split it per-locale here and let intl/ dynamically import the rest.
 *
 * Source of truth remains src/js/intl/strings.js (also used by checkStrings
 * and the translation tooling).
 */
const { writeFileSync, mkdirSync } = require('fs');
const { join } = require('path');

const { strings } = require('../src/js/intl/strings');

const OUT_DIR = join(__dirname, '..', 'src', 'js', 'intl', 'generated');

// key -> { locale: value }  ==>  locale -> { key: value }
const byLocale = {};
Object.keys(strings).forEach((key) => {
  const translations = strings[key];
  Object.keys(translations).forEach((locale) => {
    if (locale === '__desc__') { return; }
    if (!byLocale[locale]) { byLocale[locale] = {}; }
    byLocale[locale][key] = translations[locale];
  });
});

mkdirSync(OUT_DIR, { recursive: true });

const locales = Object.keys(byLocale).sort();
let totalBytes = 0;

locales.forEach((locale) => {
  const out = "'use strict';\n\n" +
    '// AUTO-GENERATED by scripts/generateIntlStrings.js -- do not edit.\n' +
    'exports.strings = ' + JSON.stringify(byLocale[locale]) + ';\n';
  writeFileSync(join(OUT_DIR, locale + '.js'), out);
  totalBytes += out.length;
});

// en_US is loaded synchronously by intl/ as the fallback; the rest stream in
// on demand. Loader keys must be static string literals for the bundler.
let loaders = "'use strict';\n\n" +
  '// AUTO-GENERATED by scripts/generateIntlStrings.js -- do not edit.\n' +
  'exports.loaders = {\n';
locales.forEach((locale) => {
  loaders += '  ' + JSON.stringify(locale) +
    ': function () { return import(' + JSON.stringify('./' + locale + '.js') + '); },\n';
});
loaders += '};\n';
writeFileSync(join(OUT_DIR, 'loaders.js'), loaders);

console.log('Generated ' + locales.length + ' locale string modules (' +
  Math.round(totalBytes / 1024) + ' KB total) in ' + OUT_DIR);