customFilter.js

app.filter('l10n', function() {

  // In the return function, we must pass in a single parameter which will be the data we will work on.
  // We have the ability to support multiple other parameters that can be passed into the filter optionally
  return function(input, key) {

    // imagine that we have some variables with parsed JSONs
    /* var JSONS = {
      'ru': ruJSON, 
      'ua': uaJSON, 
      'en': enJSON, 
      ...
    };
    */
    // p.s. you can use $http.get() - for getting json is you can not get it, but I think that you can
    
    // and global variable with key of language
    // var language = 'ua';
    
    return JSONS[language][key];

  }

});


/*
--USAGE--
{{ 'Design' | l10n : 'aside.header.notifications'}}

//so, the 'Design' is only for developers
*/