Share server store without Persister?

[waynesbrain]

Can I create a store in a server package and share it to clients over websockets but without creating a perister?

[waynesbrain]

For now I just created MemoryPersistor. I wasn't sure if I should clone my state at any point or call listeners at the end of setPersisted, but it seems to work fine without doing either of those.

import type {
  MergeableStore,
  PersistedContent,
  Persister,
  Persists,
  PersisterListener,
  Store,
  OptionalSchemas,
} from "tinybase/with-schemas";
import { createCustomPersister } from "tinybase/with-schemas";

type PContent<Schemas extends OptionalSchemas> = PersistedContent<
  Schemas,
  Persists.StoreOrMergeableStore
>;
type PListener<Schemas extends OptionalSchemas> = PersisterListener<
  Schemas,
  Persists.StoreOrMergeableStore
>;

export interface MemoryPersister<Schemas extends OptionalSchemas>
  extends Persister<Schemas, Persists.StoreOrMergeableStore> {}

export function createMemoryPersister<Schemas extends OptionalSchemas>(
  store: Store<Schemas> | MergeableStore<Schemas>,
  onIgnoredError?: (error: any) => void,
): MemoryPersister<Schemas> {
  let state: PContent<Schemas> | undefined = undefined;

  async function getPersisted(): Promise<PContent<Schemas> | undefined> {
    console.log("MEM GET");
    return state;
  }

  async function setPersisted(
    getContent: () => PContent<Schemas>,
  ): Promise<void> {
    console.log("MEM SET");
    state = getContent();
  }

  function addPersisterListener(listener: PListener<Schemas>): string {
    console.log("MEM LISTEN");
    return "subscription";
  }

  function delPersisterListener(subscription: string): void {
    console.log("MEM HANGUP");
  }

  return createCustomPersister(
    store,
    getPersisted,
    setPersisted,
    addPersisterListener,
    delPersisterListener,
    onIgnoredError,
    3, // Persists.StoreOrMergeableStore,
  ) as MemoryPersister<Schemas>;
}