code: function(dirPath, callback) {
      logger.info('getDelta start', {category: 'sync-local-delta'});
  
      async.series([
        (cb) => {
          logger.debug('findDeletedNodes start', {category: 'sync-local-delta'});
  
          this.findDeletedNodes(cb)
        },
        (cb) => {
          logger.debug('findChanges start', {category: 'sync-local-delta'});
  
          this.findChanges(dirPath, undefined, null, cb);
        },
        (cb) => {
          logger.debug('resolveConflicts start', {category: 'sync-local-delta'});
  
          this.resolveConflicts(cb);
        }
      ], (err, resuls) => {
        logger.info('getDelta end', {category: 'sync-local-delta'});
  
        return callback(null);
      });
    }
docs: Scans the given directory for new, changed and deleted nodes.
  Sets the necessary localActions in the database.
  
  @param {string} dirPath - root directory to get delta for
  @param {Function} callback - callback function
  @returns {void} - no return value