I have read the documentation but i cannot get it to work.

Currently i have this facet (sorry for it being a discord pic, i cannot upload here)
pic

with this config

"th_httpinspireeceuropaeutheme-theme_tree.key": { "terms": { "field": "th_httpinspireeceuropaeutheme-theme_tree.key", "size": 34 }, "meta": { "decorator": { "type": "icon", "prefix": "fa fa-2x pull-left gn-icon iti-tn" }, "orderByTranslation": true } },

and

"th_httpinspireeceuropaeumetadatacodelistPriorityDataset-PriorityDataset_tree.default": { "terms": { "field": "th_httpinspireeceuropaeumetadatacodelistPriorityDataset-PriorityDataset_tree.default", "size": 100, "order": { "_key": "asc" } } }, "th_httpinspireeceuropaeutheme-theme_tree.key": { "terms": { "field": "th_httpinspireeceuropaeutheme-theme_tree.key", "size": 34 }, "meta": { "decorator": { "type": "icon", "prefix": "fa fa-fw gn-icon iti-tn" } } }

but when the page loads, the icon class appends this url: http://rdfdata.eionet.europa.eu/inspirethemes/themes/7, ending like this

class="ng-scope fa fa-2x pull-left gn-icon iti-http://rdfdata.eionet.europa.eu/inspirethemes/themes/7"

which of course, doesnt show any icon, as it is appending that url, but in my config, there is no such expression to append anything, apart that as shown in the image, it doesnt even have a text.