function filterByBlockLevelMode(isBlockLevelMode) {
    return function (plugin) {
      return (isBlockLevelMode ? blockModePlugins : inlineModePlugins).indexOf(plugin) !== -1;
    }
  }
Filters a list of plugins by block level / inline level mode.

@param  {Boolean} isBlockLevelMode Whether block level mode is enabled
@return {Function}                 Filtering function based upon the given mode