Adds Yoast reading time post meta in a shortcode: [yoast-reading-time]

who-yoast-reading-time-shortcode.php

<?php
/**
 * Plugin Name: Yoast Reading Time Shortcode
 * Description: Adds Yoast reading time post meta in a shortcode.
 * Author: Jb Audras @ Whodunit
 * Version: 0.1
 * Author URI: https://whodunit.fr
 */

/**
 * Gets Yoast reading time and add it in a shortcode: [yoast-reading-time]
 */
function jba_yoast_reading_time_shortcode() {
	global $post;
	if ( is_plugin_active( 'wordpress-seo/wp-seo.php' ) || is_plugin_active( 'wordpress-seo-premium/wp-seo-premium.php' ) ) {
		$yoast_estimated_time = YoastSEO()->meta->for_post( $post->ID )->estimated_reading_time_minutes;
		// Because we don't want to show 0 minutes…
		$yoast_estimated_time = $yoast_estimated_time > 0 ? $yoast_estimated_time : 1;

		$content = sprintf(
			__( 'Estimated reading time: %s minutes.', 'who-yoast-reading-time-shortcode' ),
			$yoast_estimated_time
		);
		return $content;
	}
}
add_shortcode( 'yoast-reading-time', 'jba_yoast_reading_time_shortcode' );