facetwp replace date picker placeholder text

custom-hooks.php

<?php

/** replace the "Date" or "Start Date" or "End Date" text in the datepicker
 ** Other langauges may have different text to replace as well
 **/
add_filter( 'facetwp_facet_html', function( $output, $params ) {
	if ( 'my_date_facet' == $params['facet']['name'] ) { // change 'my_date_facet' to the name of your date picker facet
		$output = str_replace( 'placeholder="Date"', 'placeholder="mm/dd/yyyy"', $output );
	}
	return $output;
}, 10, 2 );