Gravity Forms + Wordpress — retrieve a Gravity form by its class (set in each form settings)

functions.php

<?php
// Retrieve a Gravity form by class (set in each form settings) 'js-overlay-form'
if ( class_exists( 'GFAPI' ) ) {
	$forms = GFAPI::get_forms();
	$class_key = 'cssClass';
	$contactform_class = 'js-overlay-form';
	foreach ($forms as $form) {
	  if (array_key_exists($class_key, $form) && $form[$class_key] == $contactform_class) {
	    $contactform_id = $form['id'];
	    break;
	  }
	}
}