FacetWP – translate “On Sale” text

<?php

add_filter( 'gettext', function( $translated_text, $text, $domain ) {
    if ( 'fwp-front' == $domain && 'On Sale' == $text ) {
        $translated_text = 'On Sale (TRANSLATED)';
    }
    return $translated_text;
}, 10, 3 );