FORQY — Custom Settings of the jQuery UI Datepicker

functions.php

<?php

if ( ! function_exists( 'prefix_scripts_datepicker' ) ) {

	/**
	 * Custom Settings of the jQuery UI Datepicker
	 * @url https://api.jqueryui.com/datepicker/
	 */
	function prefix_scripts_datepicker() {

		$datepicker = '
			(function ($) {
				"use strict";
				
				$(".js-datepicker").datepicker(
					// YOUR SETTINGS
				);
			}(jQuery));
		';

		wp_add_inline_script( 'jquery-ui-datepicker', $datepicker );

	}

	add_action( 'wp_enqueue_scripts', 'prefix_scripts_datepicker', 90 );

}