svelte/test/runtime/samples/component-slot-fallback-2/store.svelte

<script context="module">
  let value = 'Blub';
  let count = 0;
  const subscribers = new Set();
  export const model = {
    subscribe(fn) {
      subscribers.add(fn);
      count ++;
      fn(value);
      return () => {
        count--;
        subscribers.delete(fn);
      };
    },
    set(v) {
      value = v;
      subscribers.forEach(fn => fn(v));
    },
    getCount() {
      return count;
    }
  };
</script>