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<?php

/**
 * attaches a click even to a div that selects all of a checkbox facets available options and triggers a refresh
 * change "product_categories" to the name of your facet
 * <div class="facetwp-checkbox select-all">Select all</div> creates a div that looks like facet checkboxes
 *
 */
add_action( 'wp_head', function() { ?>
	<script>
        (function($) {
            $(document).ready(function() {
                $(".select-all").click(function () {
                    var available = [];
                    $( '.facetwp-facet-product_categories .facetwp-checkbox' ).each( function (index, item) {
                        available.push( $(item).attr( 'data-value' ) );
                    });
                    FWP.facets['product_categories'] = available;
                    FWP.is_reset = true; // don't parse facets
                    FWP.refresh();
                });
            });
        })(jQuery);
	</script>
<?php });