Get WordPress Custom Posts by Custom Taxonomy Slug

index.php

<?php
/**
* Use snippet below to Get WordPress Custom Posts by Custom Taxonomy Slug
* Developed by Amirhosseinhpv ( https://hpv.im/ )
*/

$cpt = "mapify";                      // custom post type
$cpt_taxonamy = "mapify_category";    // custom post type taxonamy
$ctp_taxonomy_slug = "official";      // custom post type taxonamy slug
  
$posts_array = get_posts(
  array(
    'posts_per_page' => -1,
    'post_type' => $cpt,
    'fields' => 'ids',                // to use fn efficiently and only retrive IDs, otherwise you can comment this line!
    'tax_query' => array(
      array(
        'taxonomy' => $cpt_taxonamy,
        'field' => 'slug',
        'terms' => $ctp_taxonomy_slug,
      )
    )
  )
);

$posts_count = count($posts_array);