Convert EPOCH timestamp to Wordpress post_date

epoch-to-wordpress-post-date.php

<?php

$timestamp = '1517341140000';

$post_arr = [
  'post_title' => 'Meh title',
  'post_type' => 'post', //could be any custom post type
  'post_content' => 'Meh body',
  'post_category' => ['meh category'],
  'post_status' => 'publish'
];

$post_arr['post_date'] = date("Y-m-d H:i:s", substr($timestamp, 0, 10));

// $post_id = wp_insert_post($post_arr);