Class: directives plus utilities — best friends.
Conditional classes#
Component.svelte
<script>
let active = false;
</script>
<button
class:active
class="px-4 py-2 rounded-lg transition"
class:bg-blue-500={active}
>Toggle</button>Patterns that scale#
- class: directives compose perfectly with utilities
- Keep component APIs as variant props mapping to class sets
Gotchas#
- class:{expr} is fine; runtime-built strings are not scanned
Tip. Dynamic class fragments must be visible to the content scanner — full class names in source, or a configuration/safelist|safelist.
