PHP

<?php
if ( ! defined( 'ABSPATH' ) ) exit;

add_action('rest_api_init', function () {
    register_rest_route('referenciak', '/v1', [
        'methods'  => 'GET',
        'callback' => 'get_referenciak_all',
        'permission_callback' => '__return_true',
    ]);
});


function get_referenciak_all(WP_REST_Request $request) {
    $query = new WP_Query([
        'post_type'              => 'referenciak',
        'post_status'            => 'publish',
        'posts_per_page'         => -1,
        'orderby'                => 'menu_order',
        'order'                  => 'ASC',
        'no_found_rows'          => true,
        'update_post_meta_cache' => true,
        'update_post_term_cache' => true,
    ]);

    $references = [];

    foreach ($query->posts as $post) {
        $terms = get_the_terms($post->ID, 'referencia-kategoria');

        if (is_wp_error($terms) || empty($terms)) {
            $terms = [];
        }

        $references[] = [
            'title'          => get_the_title($post),
            'featured_image' => get_the_post_thumbnail_url($post, 'full') ?: null,
            'taxonomy'       => array_values(array_map(function ($term) {
                return [
                    'id'   => (int) $term->term_id,
                    'name' => $term->name,
                    'slug' => $term->slug,
                ];
            }, $terms)),
        ];
    }

    return rest_ensure_response($references);
}

Specifies the format of the outputted date string. The following characters can be used:

d – The day of the month (from 01 to 31)
D – A textual representation of a day (three letters)
j – The day of the month without leading zeros (1 to 31)
l (lowercase ‘L’) – A full textual representation of a day
N – The ISO-8601 numeric representation of a day (1 for Monday, 7 for Sunday)
S – The English ordinal suffix for the day of the month (2 characters st, nd, rd or th. Works well with j)
w – A numeric representation of the day (0 for Sunday, 6 for Saturday)
z – The day of the year (from 0 through 365)
W – The ISO-8601 week number of year (weeks starting on Monday)
F – A full textual representation of a month (January through December)
m – A numeric representation of a month (from 01 to 12)
M – A short textual representation of a month (three letters)
n – A numeric representation of a month, without leading zeros (1 to 12)
t – The number of days in the given month
L – Whether it’s a leap year (1 if it is a leap year, 0 otherwise)
o – The ISO-8601 year number
Y – A four digit representation of a year
y – A two digit representation of a year
a – Lowercase am or pm
A – Uppercase AM or PM
B – Swatch Internet time (000 to 999)
g – 12-hour format of an hour (1 to 12)
G – 24-hour format of an hour (0 to 23)
h – 12-hour format of an hour (01 to 12)
H – 24-hour format of an hour (00 to 23)
i – Minutes with leading zeros (00 to 59)
s – Seconds, with leading zeros (00 to 59)
u – Microseconds (added in PHP 5.2.2)
e – The timezone identifier (Examples: UTC, GMT, Atlantic/Azores)
I (capital i) – Whether the date is in daylights savings time (1 if Daylight Savings Time, 0 otherwise)
O – Difference to Greenwich time (GMT) in hours (Example: +0100)
P – Difference to Greenwich time (GMT) in hours:minutes (added in PHP 5.1.3)
T – Timezone abbreviations (Examples: EST, MDT)
Z – Timezone offset in seconds. The offset for timezones west of UTC is negative (-43200 to 50400)
c – The ISO-8601 date (e.g. 2013-05-05T16:34:42+00:00)
r – The RFC 2822 formatted date (e.g. Fri, 12 Apr 2013 12:01:05 +0200)
U – The seconds since the Unix Epoch (January 1 1970 00:00:00 GMT)

Register CPT endpoint

PHP date format