In my case, using AngularJS, i have a json with some configurations that can be used in controllers. The problem happens when i minify the application and the controller variables name does not match with the json.
Is there a way to not minify a single variabe?
My code: setting.json
{
   "settings": {
      "adIndex": 3
    }
}
controller:
function settingsService($q, $http, $log) {
  var settings = {
    adIndex: 0
  };
  var service = {
    init: init,
    getAdIndex: getAdIndex
  };
  return service;
  function init() {
    var deferred = $q.defer();
    $http.get('assets/settings/settings.json').then(function(response) {
      var loaded = response.data.settings;
      if (loaded) {
        settings = angular.extend(settings, loaded);
      }
      deferred.resolve(settings);
    }, function(error) {
      $log.info('Error loading settings', error);
      deferred.reject(error);
    });
    return deferred.promise;
  }
  function getAdIndex() {
    return settings.adIndex;
  }
}
UPDATE
After your suggestions i made some changes on code, but the problem not yet resolved. The code in controller is now:
function settingsService($q, $http, $log) {
  var settings = {
    'adIndex': 0
  };
  var service = {
    init: init,
    getAdIndex: getAdIndex
  };
  return service;
  function init() {
    var deferred = $q.defer();
    $http.get('assets/settings/settings.json').then(function(response) {
      var loaded = response.data['settings'];
      if (loaded) {
        settings = angular.extend(settings, loaded);
      }
      deferred.resolve(settings);
    }, function(error) {
      $log.info('Error loading settings', error);
      deferred.reject(error);
    });
    return deferred.promise;
  }
  function getAdIndex() {
    $log.debug('Object: ', settings); // result: settings { adIndex: 3 }
    $log.debug('Value: ', settings['adIndex']); // result: 0 
    return settings['adIndex'];
  }
}
How can 'adIndex' have 2 different values in logs?
 
    