Get post meta shortcode in WordPress

grab-post-meta.php

<?php
/**
 * Returns post meta
 *
 * Usage:
 * [grab_post_meta id="15" key="meta_key"]
 * [grab_post_meta key="meta_key"]
 *
 * For more information on how to use this shortcode view: https://hunterwebdev.io/blog/create-a-custom-shortcode-to-grab-post-meta
 */
function grab_post_meta_shortcode_fn( $atts ) {
	$atts = extract( shortcode_atts( array(
		'post_id' => false,
		'key'     => ''
	), $atts ) );
	if ( ! $key ) {
		return;
	}
	$post_id = (int)($post_id === false ? get_the_ID() : $post_id);
	$data 	 = get_post_meta( $post_id, $key, true );
	
	if ( $data ) {
		return '<span class="grab-post-meta-value ' . sanitize_html_class('id-' . $post_id) . ' ' . sanitize_html_class('key-' . $key) . '">'. $data .'</span>';
	}
}
add_shortcode( 'grab_post_meta', 'grab_post_meta_shortcode_fn' );