What would be the best approach to translate an app?

Would

  return new Promise((resolve,reject) => {
    Puck.write("\x03",(result) => {
      if (result===null) return reject("");
      Puck.eval(`require("locale").lang`, (content,err) => {
        if (content===null) return reject(err || "");
        resolve(content);
      });
    });
  });

work in a custom html?