@data-client/core/README.md

Async State Management without the Management. REST, GraphQL, SSE, Websockets, Fetch

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Reducer/flux normalized, framework-agnostic data store. Includes managers/middleware, global referential equality guarantees,
automatic expiry policies, data normalization. Consumes [TypeScript Standard Endpoints](https://www.npmjs.com/package/@data-client/endpoint)

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**[📖Read The Docs](https://dataclient.io/docs)** &nbsp;|&nbsp; [🏁Getting Started](https://dataclient.io/docs/getting-started/installation) &nbsp;|&nbsp;
[🎮Todo Demo](https://stackblitz.com/github/reactive/data-client/tree/master/examples/todo-app?file=src%2Fpages%2FHome%2FTodoList.tsx) &nbsp;|&nbsp;
[🎮Github Demo](https://stackblitz.com/github/reactive/data-client/tree/master/examples/github-app?file=src%2Fpages%2FIssueList.tsx) &nbsp;|&nbsp;
[🎮NextJS SSR Demo](https://stackblitz.com/github/reactive/data-client/tree/master/examples/nextjs?file=components%2Ftodo%2FTodoList.tsx)

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### Framework Implementations

- [React](https://www.npmjs.com/package/@data-client/react)
- [React-Redux](https://dataclient.io/docs/guides/redux)

### Sample React Hook suspense implementation

```typescript
function useSuspense(endpoint, ...args)
  const state = useCacheState();
  const controller = useController();

  const key = args[0] !== null ? endpoint.key(...args) : '';
  const cacheResults = key && state.endpoints[key];
  const meta = state.meta[key];

  // Compute denormalized value
  const { data, expiryStatus, expiresAt } = useMemo(() => {
    return controller.getResponse(endpoint, ...args, state);
  }, [
    cacheResults,
    state.indexes,
    state.entities,
    state.entityMeta,
    meta,
    key,
  ]);

  const error = controller.getError(endpoint, ...args, state);

  // If we are hard invalid we must fetch regardless of triggering or staleness
  const forceFetch = expiryStatus === ExpiryStatus.Invalid;

  const maybePromise = useMemo(() => {
    // null params mean don't do anything
    if ((Date.now() <= expiresAt && !forceFetch) || !key) return;

    return controller.fetch(endpoint, ...args);
    // we need to check against serialized params, since params can change frequently
  }, [expiresAt, controller, key, forceFetch, state.lastReset]);

  // fully "valid" data will not suspend even if it is not fresh
  if (expiryStatus !== ExpiryStatus.Valid && maybePromise) {
    throw maybePromise;
  }

  if (error) throw error;

  return data;
}
```


## API

- [Controller](https://dataclient.io/docs/api/Controller)
  - [ctrl.fetch](https://dataclient.io/docs/api/Controller#fetch)
  - [ctrl.fetchIfStale](https://dataclient.io/docs/api/Controller#fetchIfStale)
  - [ctrl.expireAll](https://dataclient.io/docs/api/Controller#expireAll)
  - [ctrl.invalidate](https://dataclient.io/docs/api/Controller#invalidate)
  - [ctrl.invalidateAll](https://dataclient.io/docs/api/Controller#invalidateAll)
  - [ctrl.resetEntireStore](https://dataclient.io/docs/api/Controller#resetEntireStore)
  - [ctrl.set](https://dataclient.io/docs/api/Controller#set)
  - [ctrl.setResponse](https://dataclient.io/docs/api/Controller#setResponse)
  - [ctrl.setError](https://dataclient.io/docs/api/Controller#setError)
  - [ctrl.resolve](https://dataclient.io/docs/api/Controller#resolve)
  - [ctrl.subscribe](https://dataclient.io/docs/api/Controller#subscribe)
  - [ctrl.unsubscribe](https://dataclient.io/docs/api/Controller#unsubscribe)
  - [ctrl.get](https://dataclient.io/docs/api/Controller#get)
  - [ctrl.getResponse](https://dataclient.io/docs/api/Controller#getResponse)
  - [ctrl.getError](https://dataclient.io/docs/api/Controller#getError)
  - [ctrl.snapshot](https://dataclient.io/docs/api/Controller#snapshot)
  - [ctrl.getState](https://dataclient.io/docs/api/Controller#getState)
- Middleware: [LogoutManager](https://dataclient.io/docs/api/LogoutManager), [NetworkManager](https://dataclient.io/docs/api/NetworkManager), [SubscriptionManager](https://dataclient.io/docs/api/SubscriptionManager), [PollingSubscription](https://dataclient.io/docs/api/PollingSubscription), [DevToolsManager](https://dataclient.io/docs/api/DevToolsManager)
- State: createReducer(), initialState, applyManager