Show all markers on Map view

show_all_markers_on_map_view.php

<?php
function show_all_markers( $data ) {
    if ( ! isset( $data['markers'] ) ) return $data;

    $cached_markers = get_transient( 'all_geo_markers_store' );
    if ( $cached_markers ) {
        $data['markers'] = $cached_markers;
        return $data;
    }

    $geo_loc = Tribe__Events__Pro__Geo_Loc::instance();
    $events  = tribe_get_events( array(
        'posts_per_page' => -1,
        'eventDisplay'   => 'map'
    ) );

    $markers = $geo_loc->generate_markers( $events );
    set_transient( 'all_geo_markers_store', $markers, DAY_IN_SECONDS );

    $data['markers'] = $markers;

    return $data;
}

add_filter( 'tribe_events_ajax_response', 'show_all_markers' );