How to let a facet display only child terms of the current term on a taxonomy archive page?

If you have a category/tag/taxonomy term archive page with a facet on it that uses the same hierarchical category/tag/taxonomy as its data source, the facet will display all choices (terms) for which posts on that page have been indexed. And as posts can have multiple terms selected, this can include terms anywhere in the taxonomy’s term hierarchy, not only children of the archive’s current term.

To let the facet display only child terms of the archive’s current term (with or without the current term itself), you can use the facetwp_facet_render_args hook to remove all terms from the facet that are not a child term of the current term of the archive template.

If you choose to keep the current term, it is available to automatically pre-select it in the facet on page load, and again after a reset.

See also

• The facetwp_facet_render_args hook
• How to pre-select facet choices
• The facetwp_template_use_archive hook