useChannelEffect

Side-effect counterpart to useChannel. Instead of returning a reactive buffer, it invokes onEvent once per event for as long as the calling scope is alive — the idiomatic place for analytics, logging, and other fire-and-forget side effects.

<script lang="ts">
  useChannelEffect(stream, ["lifecycle", "tools"], {
    replay: false,
    onEvent(event) {
      sendAnalytics(event);
    },
    onError(error) {
      logger.error(error);
    },
  });
</script>

Reactive channels / target / enabled getters re-bind the subscription when they change. The underlying subscription is shared (ref-counted) with any matching useChannel consumer. replay defaults to false (live-only); events buffered before the effect attaches are not re-delivered.

Must be called from a reactive context (a .svelte component script or inside $effect.root).