Wordpress AJAX load more check end of posts - php

Question

My AJAX load more function doesn't check end of posts properly - it shows preloader one more time if there are no posts. This is caused by removing pleroader's hidden class every time before send ajax request.
How should I check end of posts correct?
AJAX
If response is 0 - just hide the preloader. So preloader is shown one more time when it shouldn't be.
var page = 3;
var emptyQuery = false;
function load_posts() {
page++;
var category = $('.cat-list__item.active').data('category');
$.ajax({
url: flow.ajax_url,
type: 'POST',
beforeSend: function (jqXHR) {
$('body').addClass('loading');
if ($('.preloader').length) {
$('.preloader').removeClass('preloader--hidden');
}
},
data: {
action: 'scroll_post_load',
page: page,
category: category
},
success: function (response) {
if ( response==0 ) {
emptyQuery = true;
if ($('.preloader').length) {
$('.preloader').addClass('preloader--hidden');
}
} else {
if ($('.preloader').length) {
$('.preloader').addClass('preloader--hidden');
}
var html = response;
$(html).hide().appendTo('.posts-list').fadeIn(1000);
}
$('body').removeClass('loading');
}
});
}
// Scripts which runs on scrolling
$( window ).on( 'scroll', function() {
if( $(window).scrollTop() > $('.posts-list').height() && !$('body').hasClass('loading')) {
if(emptyQuery == false) {
load_posts();
}
}
} );
PHP
If it is the last page - returns 0 in response
function scroll_post_load(){
$paged = $_POST['page'];
$category = $_POST['category'];
if( $category=='all' || !$category ) {
$args = array(
'post_type' => 'post',
'post_status' => 'publish',
'posts_per_page' => '3',
'paged' => $paged
);
}
if( $category ) {
$args = array(
'post_type' => 'post',
'post_status' => 'publish',
'posts_per_page' => '3',
'paged' => $paged,
'cat' => $category
);
}
$wp_query = new WP_Query( $args );
if ( $wp_query->max_num_pages == get_query_var('paged')) {
return '0';
}
if ($wp_query->have_posts()) :
while ($wp_query->have_posts()) : $wp_query->the_post();
show_template('loop-post');
endwhile;
endif;
wp_die();
}
add_action('wp_ajax_scroll_post_load', 'scroll_post_load');
add_action('wp_ajax_nopriv_scroll_post_load', 'scroll_post_load');

Answer 1

You can resolve this if you just return in your response what is the total number of pages and then in the script check if next page is last or something.
That's how I do it usually. I always return the max number of pages along with the content so I can check if I need to execute the AJAX call one last time.