Visual Composer Link sortcode and vc map / Anchor tag with visual composer

vc_link.php

//vc_link ++ vc_param
  array(
			'type' => 'vc_link',
			'heading' => __( 'Button', 'my-text-domain' ),
			'param_name' => 'url',
		),
//Shortcode
function vc_link_demo( $atts, $content =  null) {
		extract(shortcode_atts(array(
			'url' => ''
		), $atts));

//Link construct 
    $url = ($url=='||') ? '' : $url;
		$url = vc_build_link( $url );
		$a_link = $url['url'];
		$a_title = ($url['title'] == '') ? '' : 'title="'.$url['title'].'"';
		$a_target = ($url['target'] == '') ? '' : 'target="'.$url['target'].'"';
//Anchor Tag
    $button = $a_link ? '<a class="btn btn-md btn-black" href="'.$a_link. '" '.$a_title.' '.$a_target.'>'.$url['title'].'</a>' : '';
$anchorTag = $button;
return $anchorTag;

}
add_shortcode('link_demo', 'vc_link_demo');