spritesmith hover

https://github.com/twolfson/gulp.spritesmith/issues/18

cssOpts: {
  cssClass: function (item) {
    // If this is a hover sprite, name it as a hover one (e.g. 'home-hover' -> 'home:hover')
    if (item.name.indexOf('-hover') !== -1) {
      return '.sprite-' + item.name.replace('-hover', ':hover');
    // Otherwise, use the name as the selector (e.g. 'home' -> 'home')
    } else {
      return '.sprite-' + item.name;
    }
  }
}

sass로

.icon-email {
  @include sprite($icon-email);

  &:hover {
    @include sprite($icon-email-hover);
  }
}