README.md

April 28, 2026 · View on GitHub

The scalable way to build applications with dynamic data.

Declarative resouce definitons for REST, GraphQL, Websockets+SSE and more
Performant rendering in React, NextJS, React Native, Expo, Vue

Schema driven. Zero updater functions.

Installation

npm install --save @data-client/react @data-client/rest @data-client/test

For more details, see the Getting Started docs page.

Skills

npx skills add reactive/data-client

Then run skill "data-client-setup"

Usage

Simple TypeScript definition

class User extends Entity {
  id = '';
  username = '';
}

class Article extends Entity {
  id = '';
  title = '';
  body = '';
  author = User.fromJS();
  createdAt = Temporal.Instant.fromEpochMilliseconds(0);

  static schema = {
    author: User,
    createdAt: Temporal.Instant.from,
  };
}

Create collection of API Endpoints

const UserResource = resource({
  path: '/users/:id',
  schema: User,
  optimistic: true,
});

const ArticleResource = resource({
  path: '/articles/:id',
  schema: Article,
  searchParams: {} as { author?: string },
  optimistic: true,
  paginationField: 'cursor',
});

One line data binding

const article = useSuspense(ArticleResource.get, { id });
return (
  <article>
    <h2>
      {article.title} by {article.author.username}
    </h2>
    <p>{article.body}</p>
  </article>
);

Reactive Mutations

const ctrl = useController();
return (
  <>
    <CreateArticleForm
      onSubmit={article =>
        ctrl.fetch(ArticleResource.getList.push, { id }, article)
      }
    />
    <ProfileForm
      onSubmit={user =>
        ctrl.fetch(UserResource.update, { id: article.author.id }, user)
      }
    />
    <button onClick={() => ctrl.fetch(ArticleResource.delete, { id })}>
      Delete
    </button>
  </>
);

Subscriptions

const price = useLive(PriceResource.get, { symbol });
return price.value;

Type-safe Imperative Actions

const ctrl = useController();
await ctrl.fetch(ArticleResource.update, { id }, articleData);
await ctrl.fetchIfStale(ArticleResource.get, { id });
ctrl.expireAll(ArticleResource.getList);
ctrl.invalidate(ArticleResource.get, { id });
ctrl.invalidateAll(ArticleResource.getList);
ctrl.setResponse(ArticleResource.get, { id }, articleData);
ctrl.set(Article, { id }, articleData);

Programmatic queries

const queryTotalVotes = new Query(
  new Collection([BlogPost]),
  posts => posts.reduce((total, post) => total + post.votes, 0),
);

const totalVotes = useQuery(queryTotalVotes);
const totalVotesForUser = useQuery(queryTotalVotes, { userId });

const groupTodoByUser = new Query(
  TodoResource.getList.schema,
  todos => Object.groupBy(todos, todo => todo.userId),
);
const todosByUser = useQuery(groupTodoByUser);

Powerful Middlewares

class LoggingManager implements Manager {
  middleware: Middleware = controller => next => async action => {
    console.log('before', action, controller.getState());
    await next(action);
    console.log('after', action, controller.getState());
  };

  cleanup() {}
}

class TickerStream implements Manager {
  middleware: Middleware = controller => {
    this.handleMsg = msg => {
      controller.set(Ticker, { id: msg.id }, msg);
    };
    return next => action => next(action);
  };

  init() {
    this.websocket = new WebSocket('wss://ws-feed.myexchange.com');
    this.websocket.onmessage = event => {
      const msg = JSON.parse(event.data);
      this.handleMsg(msg);
    };
  }
  cleanup() {
    this.websocket.close();
  }
}

Integrated data mocking

const fixtures = [
  {
    endpoint: ArticleResource.getList,
    args: [{ maxResults: 10 }] as const,
    response: [
      {
        id: '5',
        title: 'first post',
        body: 'have a merry christmas',
        author: { id: '10', username: 'bob' },
        createdAt: new Date(0).toISOString(),
      },
      {
        id: '532',
        title: 'second post',
        body: 'never again',
        author: { id: '10', username: 'bob' },
        createdAt: new Date(0).toISOString(),
      },
    ],
  },
  {
    endpoint: ArticleResource.update,
    response: ({ id }, body) => ({
      ...body,
      id,
    }),
  },
];

const Story = () => (
  <MockResolver fixtures={options[result]}>
    <ArticleList maxResults={10} />
  </MockResolver>
);

...all typed ...fast ...and consistent

For the small price of 9kb gziped. 🏁Get started now

Features

Examples

Todo: | |
Github: |
NextJS: | |
Websockets: | |

API

Reactive Applications

Rendering: useSuspense(), useLive(), useCache(), useDLE(), useQuery(), useLoading(), useDebounce(), useCancelling()

Event handling: useController() returns Controller

Method	Subject
Fetch
ctrl.fetch	Endpoint + Args
ctrl.fetchIfStale	Endpoint + Args
Expiry
ctrl.expireAll	Endpoint
ctrl.invalidate	Endpoint + Args
ctrl.invalidateAll	Endpoint
ctrl.resetEntireStore	Everything
Set
ctrl.set	Schema + Args
ctrl.setResponse	Endpoint + Args
ctrl.setError	Endpoint + Args
ctrl.resolve	Endpoint + Args
Subscription
ctrl.subscribe	Endpoint + Args
ctrl.unsubscribe	Endpoint + Args

Components: <DataProvider/>, <AsyncBoundary/>, <ErrorBoundary/>, <MockResolver/>
Data Mocking: Fixture, Interceptor, renderDataHook()
Middleware: LogoutManager, NetworkManager, SubscriptionManager, PollingSubscription, DevToolsManager

Define Data

Networking definition

Data model
Data Type	Mutable	Schema	Description	Queryable
Object	✅	Entity, EntityMixin	single unique object	✅
	✅	Union(Entity)	polymorphic objects (`A \| B`)	✅
	🛑	Object	statically known keys	🛑
		Invalidate(Entity)	delete an entity	🛑
List	✅	Collection(Array)	growable lists	✅
	🛑	Array	immutable lists	🛑
		All	list of all entities of a kind	✅
Map	✅	Collection(Values)	growable maps	✅
Map	🛑	Values	immutable maps	🛑
Scalar	✅	Scalar	lens-dependent entity fields	✅
any		Query(Queryable)	memoized custom transforms	✅
any		Lazy(Schema)	deferred denormalization	✅