function wp_localize_jquery_ui_datepicker() {
    global $wp_locale;

    if ( wp_script_is( 'jquery-ui-datepicker', 'enqueued' ) ) {
        return;
    }

    // Convert the PHP date format into jQuery UI's format.
    $datepicker_date_format = str_replace(
        array(
            'd', 'j', 'l', 'z', // Day.
            'F', 'M', 'n', 'm', // Month.
            'Y', 'y'            // Year.
        ),
        array(
            'dd', 'd', 'DD', 'o',
            'MM', 'M', 'm', 'mm',
            'yy', 'y'
        ),
        get_option( 'date_format' )
    );

    $datepicker_defaults = wp_json_encode( array(
        'closeText'       => __( 'Close' ),
        'currentText'     => __( 'Today' ),
        'monthNames'      => array_values( $wp_locale->month ),
        'monthNamesShort' => array_values( $wp_locale->month_abbrev ),
        'nextText'        => __( 'Next' ),
        'prevText'        => __( 'Previous' ),
        'dayNames'        => array_values( $wp_locale->weekday ),
        'dayNamesShort'   => array_values( $wp_locale->weekday_abbrev ),
        'dayNamesMin'     => array_values( $wp_locale->weekday_initial ),
        'dateFormat'      => $datepicker_date_format,
        'firstDay'        => absint( get_option( 'start_of_week' ) ),
        'isRTL'           => $wp_locale->is_rtl(),
    ) );

    wp_enqueue_script( 'jquery-ui-datepicker', '/jquery-ui-datepicker-custom.js', array(), '1.0' );
    wp_add_inline_script( 'jquery-ui-datepicker', "jQuery(document).ready(function(jQuery){jQuery.datepicker.setDefaults({$datepicker_defaults});});" );
}