I would appreciate it if we clarify some things so that i understand what you are trying to do.
For this I need some fields of type textarea. The actual Joomla! article field remains empty. Unfortunately, Joomla Core-Smartsearch does not find any content that is in custom fields. My idea was to use Jfilter to get around this limitation.
From my understanding you want to use JFilters to advance the search functionality of the Smart Search.
I.e. Render the Smart Search able to search into your custom fields. Is this right?
As wrote in your other ticket, JFilters and Smart Search are 2 distinct components. They can co-operate in the sense that the results of the Smart Search can be filtered by JFilters.
But in essence they do different things. Smart Search performs search and JFilters performs filtering and the one is not changing the way the other works.
Btw. There is a thought from our side, to develop a plugin that allows the Smart Search to lookup in custom fields but there is not a definite decision yet.
Kind regards,
Sakis Terzis
Founder and Lead Developer