Exclude some terms form the ElasticPress Facets Widget Filter

elasticpress-remove-terms-from-facet-widget.php

<?php
// Exclude some terms form the ElasticPress Facets Widget Filter
add_action(
    'pre_get_terms',
    function ( $wp_term_query ) {
        global $wp_query;

        if ( ! $wp_query->get( 'ep_facet', false ) ) {
            return false;
        }

        $feature = \ElasticPress\Features::factory()->get_registered_feature( 'facets' );

        if ( ! $feature->is_active() || ! $feature->is_facetable( $wp_query ) ) {
            return false;
        }

        if ( in_array( 'category', $wp_term_query->query_vars['taxonomy'], true ) ) {
            $wp_term_query->query_vars['exclude_tree'] = [ 1 ]; // Term IDs to exclude.
        }
    }
);