Convert directory path to css class names for images using nodeJS

gistfile1.txt

var path = '/dir1/dir2/img_folder/dir3/dir5/imagename.png';
var path_arr = path.split('/');
var img_dir = 'img_folder';
var img_ext = '.png';

var img_index = path_arr.indexOf(img_dir);
var img_dirs = path_arr.splice( (img_index + 1 ) );
var image = img_dirs.pop().replace('.png', '');

var css_class = '.image-' + img_dirs.concat(image).join('-');

console.log(css_class);