Function createRegistry

src/state/registry/create-registry.ts:21–167

()

}

export default function createRegistry(): Registry {
  const entries: EntryMap = {
    draggables: {},
    droppables: {},
  };

  const subscribers: Subscriber[] = [];

  function subscribe(cb: Subscriber): Unsubscribe {
    subscribers.push(cb);

    return function unsubscribe(): void {
      const index: number = subscribers.indexOf(cb);

      // might have been removed by a clean
      if (index === -1) {
        return;
      }

      subscribers.splice(index, 1);
    };
  }

  function notify(event: RegistryEvent) {
    if (subscribers.length) {
      subscribers.forEach((cb) => cb(event));
    }
  }

  function findDraggableById(id: DraggableId): DraggableEntry | null {
    return entries.draggables[id] || null;
  }

  function getDraggableById(id: DraggableId): DraggableEntry {
    const entry: DraggableEntry | null = findDraggableById(id);
    invariant(entry, `Cannot find draggable entry with id [${id}]`);
    return entry;
  }

  const draggableAPI: DraggableAPI = {
    register: (entry: DraggableEntry) => {
      entries.draggables[entry.descriptor.id] = entry;
      notify({ type: 'ADDITION', value: entry });
    },
    update: (entry: DraggableEntry, last: DraggableEntry) => {
      const current: DraggableEntry | null =
        entries.draggables[last.descriptor.id];

      // item already removed
      if (!current) {
        return;
      }

      // id already used for another mount
      if (current.uniqueId !== entry.uniqueId) {
        return;
      }