code: function(user, size) {
        var email = (user.email || '').trim().toLowerCase();
        var name = user.name || 'default';
  
        var d = 'd=blank';
        if (!size || size < 120) {
          d =
            'd=' +
            encodeURIComponent(
              'https://jsbin-gravatar.herokuapp.com/' + name + '.png'
            );
        }
  
        var hash = crypto
          .createHash('md5')
          .update(email)
          .digest('hex');
        return user.email
          ? 'https://www.gravatar.com/avatar/' +
              hash +
              '?s=' +
              (size || 29) +
              '&' +
              d
          : user.avatar;
      }
docs: Returns a gravatar url for the email address provided. An optional size parameter can be provided to specify the size of the avatar to generate.