getDublicates = tiddler => {

  const id = getId(tiddler);

  if (!id) {

    return [];

  }

  const tiddlers = wikiUtils.getTiddlersWithField('tmap.id', id, {limit: 2});
  delete tiddlers[wikiUtils.getTiddlerRef(tiddler)];

  return Object.keys(tiddlers);

}
Returns all other tiddlers that have the same tmap.id field entry.

Note: typically tiddlers don't have the same id assigned, however,
this can happen when tiddlers are imported or cloned.

@param {Tiddler} tiddler
@return {array<TiddlerReference>} a list of tiddlers with the same id as the
   provided tiddler (excluding the provided tiddler itself).