Add an SMS button to Scriptless Social Sharing

functions.php

<?php

add_filter( 'kses_allowed_protocols', 'prefix_allow_sms' );
/**
 * Add sms to the list of allowed URL protocols in WordPress.
 * @param $protocols
 *
 * @return array
 */
function prefix_allow_sms( $protocols ) {
	$protocols[] = 'sms';
	return $protocols;
}

add_filter( 'scriptlesssocialsharing_sms_url', 'prefix_add_sms', 10, 3 );
/**
 * Create the URL for the SMS sharing button.
 * @param $url
 * @param $button
 * @param $attributes
 *
 * @return string
 */
function prefix_add_sms( $url, $button, $attributes ) {
	return sprintf( 'sms:?&body=%s %s %s', $attributes['email_subject'], $attributes['title'], $attributes['permalink'] );
}

add_filter( 'scriptlesssocialsharing_networks', 'prefix_scriptless_networks' );
/**
 * Add SMS to settings/allowed sharing buttons
 * @param $networks
 *
 * @return mixed
 */
function prefix_scriptless_networks( $networks ) {
	$networks['sms']      = array(
		'name'  => 'sms',
		'label' => __( 'SMS', 'scriptless-social-sharing' ),
		'icon'  => 'f27b',
		'color' => '#009933',
	);
	return $networks;
}