habitica/website/client/libs/i18n.js

// Vue plugin to globally expose a '$t' method that calls common/i18n.t.
// Can be anywhere inside vue as 'this.$t' or '$t' in templates.

import i18n from 'common/script/i18n';
import moment from 'moment';

export default {
  install (Vue, {i18nData}) {
    if (i18nData) {
      // Load i18n strings
      i18n.strings = i18nData.strings;

      // Load Moment.js locale
      const language = i18nData.language;

      if (language && i18nData.momentLang && language.momentLangCode) {
        // Make moment available under `window` so that the locale can be set
        window.moment = moment;

        // Execute the script and set the locale
        const head = document.getElementsByTagName('head')[0];
        const script = document.createElement('script');
        script.type = 'text/javascript';
        script.text = i18nData.momentLang;
        head.appendChild(script);
        moment.locale(language.momentLangCode);
      }
    }

    Vue.prototype.$t = function translateString () {
      return i18n.t.apply(null, arguments);
    };
  },
};