docs: function findFiles( root, _filters, index = 0 ) {
      if ( !FS.existsSync( root ) ) return [];
      if ( !isDirectory( root ) ) return [];
  
      const filters = Array.isArray( _filters ) ? _filters : [_filters];
      if ( index >= filters.length ) return [];
  
      let files = [];
      if ( filters.length > index + 1 ) {
          // Looking for directories.
          const filter = filters[ index ];
          FS.readdirSync( root ).forEach(function ( filename ) {
              if ( isDirectory( Path.join( root, filename ) ) ) {
                  if ( !filters || !filter || filter.test( filename ) ) {
                      files = files.concat(findFiles( Path.join( root, filename ), filters, index + 1 ));
                  }
              }
          });
      } else {
          // Looking for files.
          const filter = filters[ index ];
          FS.readdirSync( root ).forEach(function ( filename ) {
              if ( isDirectory( Path.join( root, filename ) ) ) return;
              if ( !filters || !filter || filter.test( filename ) ) {
                  files.push(Path.join( root, filename ));
              }
          });
      }
      return files;
  }