hubl/src/scripts/intl.js

/*
  js intl, inspired by danabr/jsI18n
*/
class JsI18n {

  constructor() {
    this.locale = ""; //Current locale
    this.locales = new Array(); //Available locales
  }

  /*
    Method for automatically detecting the language, does not work in every browser.
  */
  detectLanguage() {
    if (localStorage.getItem('language') || (window.navigator.language !== null && window.navigator.language !== undefined)) {
      this.setLocale(localStorage.getItem('language') || window.navigator.language.slice(0, 2));
    } else {
      console.error('Language not found');
      this.setLocale('fr');
    }
  };

  /*
    Translates tag contents and
    attributes depending on the
    value of key.
  */
  translateTag(node, key) {
    if (key.indexOf("=") == -1) { //Simple key
      this.translateNodeContent(node, key);
    } else { //Attribute/key pairs
      var parts = key.split(";");

      for (var i = 0; i < parts.length; i++) {
        var pair = parts[i].split("=");
        var attr = pair[0].toLowerCase().trim();
        var k = pair[1].trim();

        if (attr == "html") {
          this.translateNodeContent(node, k);
        } else {
          if(node.tagName == "SOLID-DELETE") {
            let button = node.querySelector('button');
            if(button != null) {
              this.translateNodeContent(button, k);
            }
          }
          this.translateNodeContent(node.attributes[attr], k);
        }
      }
    }
  }

  /**
    Replace the content of the given node
    if there is a translation for the given key.
  **/
  translateNodeContent(node, key) {
    var translation = this.t(key);
    if (node != null && translation != undefined) {
      if (node.nodeType == 1) { //Element
        try {
          node.innerHTML = translation;
        } catch (e) {
          node.text = translation;
        }
      } else if (node.nodeType == 2) { //Attribute
        node.value = translation;
      }
    }
  }

  /*
    Helper for translating a node
    and all its child nodes.
  */
  processNode(node) {
    if (node != undefined) {
      if (node.nodeType == 1) { //Element node

        var key = node.attributes["data-trans"];
        if (key != null) {
          this.translateTag(node, key.nodeValue);
        }
      }

      //Process child nodes
      var children = node.childNodes;
      for (var i = 0; i < children.length; i++) {
        this.processNode(children[i]);
      }
    }
  }

  /*
    Adds a locale to the list,
    replacing the translations
    if the locale is already defined.
  */
  addLocale(locale, translations) {
    this.locales[locale.toString()] = translations;
  }

  /*
    Sets the locale to use when translating.
  */
  setLocale(locale) {
    try {
      fetch(`/locales/${locale}.json`).then((result) => {
        if (result.ok) {
          result.json().then(e => {
            this.addLocale(locale, e);
            this.processPage();
          }).catch(() => {
            if (locale != "fr") {
              console.warn(`Locale not found: ${locale}, fallback to french`);
              this.setLocale("fr");
            } else {
              console.error("Language not found");
            }
          });
        } else {
            if (locale != "fr") {
              console.warn(`Locale not found: ${locale}, fallback to french`);
              this.setLocale("fr");
            } else {
              console.error("Language not found");
            }
        }
      });
      this.locale = locale;
    } catch {
      if (locale != "fr") {
        console.warn(`Locale not found: ${locale}, fallback to french`);
        this.setLocale("fr");
      } else {
        console.error("Language not found");
      }
    }
  }

  /*
    Fetches the translation associated with the given key.
  */
  t(key) {
    var translations = this.locales[this.locale];
    if (translations != undefined) {
      let translation = key.toString().split('.').reduce((o, i) => (o ? o[i] : undefined), translations);
      if(typeof translation == "string") {
        return translation;
      } else {
        return translations[key.toString()];
      }
    }
    return undefined;
  }

  /*
    Alias for JsI18n.t
  */
  translate(key) {
    this.t(key);
  }

  /**
    Replaces the contents of all tags
    that have the data-trans attribute set.
  **/
  processPage() {
    this.processNode(document.getElementsByTagName("html")[0]);
  }
}

//Global
jsI18n = new JsI18n;

document.addEventListener("DOMContentLoaded", () => {

  // Detect the lang & initialize, based on the browser or "language" item from localstorage
  jsI18n.detectLanguage();
  
  /*
    recursivePopulate(DOMElement)
    Will listen for the populate event of any sib element
    Process the changed node every time it populate
    Recursively add a populate listener for children elements
  */
  function recursivePopulate(element) {
    Array.from(element.querySelectorAll('*')).forEach((e) => {
      if(e.content && e.content instanceof DocumentFragment) {
        recursivePopulate(e.content);
      } else if(e instanceof HTMLElement) {
        e.addEventListener("populate", (el) => {
          recursivePopulate(el.target);
          jsI18n.processNode(el.target);
        });
      }
    });
  }
  // Process every children from document
  recursivePopulate(document);
});