feat(v1.1.6-client): @picloud/client TypeScript package

First frontend library (v1.0.0), co-shipped with realtime. Hybrid
model — no direct service access from the browser.

- endpoint<Req,Res>(path).get()/.post() — typed HTTP, auth-token
  injection, structured errors, optional zod/valibot validate adapter.
- subscribe(topic, cb, {token, onTokenExpired}) — streaming-fetch SSE
  with exponential-backoff reconnect, 401 token refresh, Last-Event-ID
  resume.
- auth.login/logout/token over dev-defined endpoints.
- React (useTopic/useEndpoint + PicloudProvider) and Svelte
  (topicStore/endpointStore) subpath exports.

Build: tsup (ESM+CJS+.d.ts); tests: vitest (15); lint: tsc --noEmit.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

clients/typescript/tests/auth.test.ts

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+import { describe, expect, it, vi } from 'vitest';
+
+import { PicloudClient } from '../src/index.js';
+import { jsonResponse, lastUrl, type FetchArgs } from './helpers.js';
+
+describe('auth', () => {
+  it('login POSTs credentials and stores the returned token', async () => {
+    const fetchMock = vi.fn(async (_u: FetchArgs[0], _i?: FetchArgs[1]) =>
+      jsonResponse({ token: 'session-abc' })
+    );
+    const client = new PicloudClient({ baseURL: 'https://api.test', fetch: fetchMock });
+
+    const token = await client.auth.login('alice@example.com', 'pw');
+    expect(token).toBe('session-abc');
+    expect(client.auth.token).toBe('session-abc');
+    expect(lastUrl(fetchMock)).toBe('https://api.test/api/auth/login');
+
+    const init = fetchMock.mock.calls[0]?.[1];
+    expect(JSON.parse(String(init?.body))).toEqual({
+      email: 'alice@example.com',
+      password: 'pw'
+    });
+  });
+
+  it('logout clears the stored token', async () => {
+    const fetchMock = vi.fn(async (_u: FetchArgs[0], _i?: FetchArgs[1]) => jsonResponse({}));
+    const client = new PicloudClient({ baseURL: 'https://api.test', fetch: fetchMock });
+    client.auth.setToken('existing');
+    await client.auth.logout();
+    expect(client.auth.token).toBeNull();
+  });
+
+  it('provider returns the current token for getAuthToken wiring', async () => {
+    const fetchMock = vi.fn(async (_u: FetchArgs[0], _i?: FetchArgs[1]) =>
+      jsonResponse({ token: 't' })
+    );
+    const client = new PicloudClient({ baseURL: 'https://api.test', fetch: fetchMock });
+    await client.auth.login('a@b.c', 'pw');
+    expect(client.auth.provider()).toBe('t');
+  });
+});

clients/typescript/tests/endpoint.test.ts

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+import { describe, expect, it, vi } from 'vitest';
+
+import { PicloudClient, PicloudHttpError } from '../src/index.js';
+import { headerOf, jsonResponse, lastInit, lastUrl, type FetchArgs } from './helpers.js';
+
+describe('endpoint', () => {
+  it('post round-trips a typed request/response', async () => {
+    const fetchMock = vi.fn(async (_u: FetchArgs[0], _i?: FetchArgs[1]) =>
+      jsonResponse({ id: '1', name: 'alice', created_at: 'now' }, 201)
+    );
+    const client = new PicloudClient({ baseURL: 'https://api.test', fetch: fetchMock });
+
+    interface Req {
+      name: string;
+      role: string;
+    }
+    interface Res {
+      id: string;
+      name: string;
+      created_at: string;
+    }
+    const res = await client.endpoint<Req, Res>('/api/users').post({ name: 'alice', role: 'admin' });
+
+    expect(res).toEqual({ id: '1', name: 'alice', created_at: 'now' });
+    expect(lastUrl(fetchMock)).toBe('https://api.test/api/users');
+    const init = lastInit(fetchMock);
+    expect(init.method).toBe('POST');
+    expect(JSON.parse(String(init.body))).toEqual({ name: 'alice', role: 'admin' });
+    expect(headerOf(init, 'Content-Type')).toBe('application/json');
+  });
+
+  it('get round-trips', async () => {
+    const fetchMock = vi.fn(async (_u: FetchArgs[0], _i?: FetchArgs[1]) =>
+      jsonResponse({ name: 'bob' })
+    );
+    const client = new PicloudClient({ baseURL: 'https://api.test', fetch: fetchMock });
+    const res = await client.endpoint<unknown, { name: string }>('/api/users/1').get();
+    expect(res.name).toBe('bob');
+    expect(lastInit(fetchMock).method).toBe('GET');
+  });
+
+  it('injects the auth token from getAuthToken', async () => {
+    const fetchMock = vi.fn(async (_u: FetchArgs[0], _i?: FetchArgs[1]) => jsonResponse({ ok: true }));
+    const client = new PicloudClient({
+      baseURL: 'https://api.test',
+      fetch: fetchMock,
+      getAuthToken: () => 'tok-123'
+    });
+    await client.endpoint('/api/me').get();
+    expect(headerOf(lastInit(fetchMock), 'Authorization')).toBe('Bearer tok-123');
+  });
+
+  it('throws PicloudHttpError with status + body on non-2xx', async () => {
+    const fetchMock = vi.fn(async (_u: FetchArgs[0], _i?: FetchArgs[1]) =>
+      jsonResponse({ error: 'bad input' }, 422)
+    );
+    const client = new PicloudClient({ baseURL: 'https://api.test', fetch: fetchMock });
+    const err = await client
+      .endpoint('/api/x')
+      .get()
+      .catch((e: unknown) => e);
+    expect(err).toBeInstanceOf(PicloudHttpError);
+    expect((err as PicloudHttpError).status).toBe(422);
+    expect((err as PicloudHttpError).message).toBe('bad input');
+  });
+
+  it('applies an optional validator to the response', async () => {
+    const fetchMock = vi.fn(async (_u: FetchArgs[0], _i?: FetchArgs[1]) =>
+      jsonResponse({ id: 7 })
+    );
+    const client = new PicloudClient({ baseURL: 'https://api.test', fetch: fetchMock });
+    const validator = {
+      parse: (input: unknown) => {
+        const r = input as { id: number };
+        if (typeof r.id !== 'number') throw new Error('bad');
+        return r;
+      }
+    };
+    const res = await client.endpoint<unknown, { id: number }>('/api/x').get({ validate: validator });
+    expect(res.id).toBe(7);
+  });
+});

clients/typescript/tests/helpers.ts

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+// Test helpers: build JSON + SSE Response objects and a typed fetch mock.
+
+export function jsonResponse(body: unknown, status = 200): Response {
+  return new Response(JSON.stringify(body), {
+    status,
+    headers: { 'content-type': 'application/json' }
+  });
+}
+
+export function emptyResponse(status = 200): Response {
+  return new Response(null, { status });
+}
+
+/** Build a text/event-stream Response from raw SSE frame strings. */
+export function sseResponse(frames: string[], status = 200): Response {
+  const encoder = new TextEncoder();
+  const stream = new ReadableStream<Uint8Array>({
+    start(controller) {
+      for (const frame of frames) controller.enqueue(encoder.encode(frame));
+      controller.close();
+    }
+  });
+  return new Response(stream, {
+    status,
+    headers: { 'content-type': 'text/event-stream' }
+  });
+}
+
+/** One SSE `data:` event frame for a realtime payload. */
+export function dataFrame(topic: string, message: unknown, publishedAt = '2026-06-04T00:00:00Z'): string {
+  const payload = JSON.stringify({ topic, message, published_at: publishedAt });
+  return `data: ${payload}\n\n`;
+}
+
+export type FetchArgs = [string | URL | Request, RequestInit?];
+
+type MockLike = { mock: { calls: ReadonlyArray<ReadonlyArray<unknown>> } };
+
+export function lastInit(mock: MockLike, i = 0): RequestInit {
+  const call = mock.mock.calls[i];
+  if (!call) throw new Error(`no fetch call at index ${i}`);
+  return (call[1] as RequestInit | undefined) ?? {};
+}
+
+export function lastUrl(mock: MockLike, i = 0): string {
+  const call = mock.mock.calls[i];
+  if (!call) throw new Error(`no fetch call at index ${i}`);
+  return String(call[0]);
+}
+
+export function headerOf(init: RequestInit, name: string): string | undefined {
+  const h = init.headers as Record<string, string> | undefined;
+  return h?.[name];
+}

clients/typescript/tests/react.test.tsx

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+import { act, renderHook } from '@testing-library/react';
+import type { ReactNode } from 'react';
+import { describe, expect, it, vi } from 'vitest';
+
+import type { PicloudClient, RealtimeEvent, Unsubscribe } from '../src/index.js';
+import { PicloudProvider, useTopic } from '../src/react/index.js';
+
+type Cb = (e: RealtimeEvent<unknown>) => void;
+
+function fakeClient() {
+  const unsubscribe = vi.fn();
+  let captured: Cb | null = null;
+  const subscribe = vi.fn(
+    (_topic: string, cb: Cb): Unsubscribe => {
+      captured = cb;
+      return unsubscribe as unknown as Unsubscribe;
+    }
+  );
+  const client = { subscribe } as unknown as PicloudClient;
+  return { client, subscribe, unsubscribe, emit: (e: RealtimeEvent<unknown>) => captured?.(e) };
+}
+
+describe('react useTopic', () => {
+  it('subscribes on mount, accumulates messages, unsubscribes on unmount', () => {
+    const { client, subscribe, unsubscribe, emit } = fakeClient();
+    const wrapper = ({ children }: { children: ReactNode }) =>
+      PicloudProvider({ client, children });
+
+    const { result, unmount } = renderHook(() => useTopic<{ n: number }>('chat'), { wrapper });
+
+    expect(subscribe).toHaveBeenCalledTimes(1);
+    expect(result.current).toEqual([]);
+
+    act(() => emit({ topic: 'chat', message: { n: 1 }, published_at: 't' }));
+    act(() => emit({ topic: 'chat', message: { n: 2 }, published_at: 't' }));
+    expect(result.current).toEqual([{ n: 1 }, { n: 2 }]);
+
+    unmount();
+    expect(unsubscribe).toHaveBeenCalledTimes(1);
+  });
+});

clients/typescript/tests/subscribe.test.ts

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+import { describe, expect, it, vi } from 'vitest';
+
+import { PicloudClient, type RealtimeEvent } from '../src/index.js';
+import { dataFrame, emptyResponse, lastUrl, sseResponse, type FetchArgs } from './helpers.js';
+
+/** A fetch mock that plays through a queue of response factories. */
+function queuedFetch(responders: Array<() => Promise<Response>>) {
+  let i = 0;
+  return vi.fn(async (_u: FetchArgs[0], _i?: FetchArgs[1]) => {
+    const idx = Math.min(i, responders.length - 1);
+    i += 1;
+    const r = responders[idx];
+    if (!r) throw new Error('no responder');
+    return r();
+  });
+}
+
+describe('subscribe', () => {
+  it('connects to the SSE endpoint and delivers events', async () => {
+    const fetchMock = queuedFetch([async () => sseResponse([dataFrame('chat', { hi: 1 })])]);
+    const client = new PicloudClient({ baseURL: 'https://api.test', fetch: fetchMock });
+
+    const received: Array<RealtimeEvent<{ hi: number }>> = [];
+    const unsubscribe = client.subscribe<{ hi: number }>('chat', (e) => received.push(e));
+
+    await vi.waitFor(() => expect(received.length).toBe(1));
+    unsubscribe();
+
+    expect(received[0]?.topic).toBe('chat');
+    expect(received[0]?.message).toEqual({ hi: 1 });
+    expect(lastUrl(fetchMock)).toBe('https://api.test/realtime/topics/chat');
+  });
+
+  it('passes a token via the query string', async () => {
+    const fetchMock = queuedFetch([async () => sseResponse([dataFrame('chat', 1)])]);
+    const client = new PicloudClient({ baseURL: 'https://api.test', fetch: fetchMock });
+    const unsubscribe = client.subscribe('chat', () => {}, { token: 'abc.def' });
+    await vi.waitFor(() => expect(fetchMock).toHaveBeenCalled());
+    unsubscribe();
+    expect(lastUrl(fetchMock)).toBe('https://api.test/realtime/topics/chat?token=abc.def');
+  });
+
+  it('reconnects with backoff after an initial connection failure', async () => {
+    const fetchMock = queuedFetch([
+      async () => {
+        throw new Error('network down');
+      },
+      async () => sseResponse([dataFrame('chat', { ok: true })])
+    ]);
+    const client = new PicloudClient({ baseURL: 'https://api.test', fetch: fetchMock });
+
+    const received: unknown[] = [];
+    const unsubscribe = client.subscribe('chat', (e) => received.push(e.message), {
+      baseBackoffMs: 5,
+      maxBackoffMs: 20
+    });
+
+    await vi.waitFor(() => expect(received.length).toBeGreaterThanOrEqual(1), { timeout: 1000 });
+    unsubscribe();
+    expect(fetchMock.mock.calls.length).toBeGreaterThanOrEqual(2);
+    expect(received[0]).toEqual({ ok: true });
+  });
+
+  it('refreshes the token after a 401 and reconnects', async () => {
+    const fetchMock = queuedFetch([
+      async () => emptyResponse(401),
+      async () => sseResponse([dataFrame('chat', { v: 2 })])
+    ]);
+    const client = new PicloudClient({ baseURL: 'https://api.test', fetch: fetchMock });
+
+    const onTokenExpired = vi.fn(() => 'fresh-token');
+    const received: unknown[] = [];
+    const unsubscribe = client.subscribe('chat', (e) => received.push(e.message), {
+      token: 'stale',
+      onTokenExpired,
+      baseBackoffMs: 5
+    });
+
+    await vi.waitFor(() => expect(received.length).toBeGreaterThanOrEqual(1), { timeout: 1000 });
+    unsubscribe();
+
+    expect(onTokenExpired).toHaveBeenCalled();
+    // Second connect carries the refreshed token.
+    expect(lastUrl(fetchMock, 1)).toContain('token=fresh-token');
+    expect(received[0]).toEqual({ v: 2 });
+  });
+
+  it('stops and reports when a 401 cannot be refreshed', async () => {
+    const fetchMock = queuedFetch([async () => emptyResponse(401)]);
+    const client = new PicloudClient({ baseURL: 'https://api.test', fetch: fetchMock });
+    const onError = vi.fn();
+    const unsubscribe = client.subscribe('chat', () => {}, {
+      onTokenExpired: () => null,
+      onError
+    });
+    await vi.waitFor(() => expect(onError).toHaveBeenCalled());
+    unsubscribe();
+  });
+});

clients/typescript/tests/svelte.test.ts

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+import { get } from 'svelte/store';
+import { describe, expect, it, vi } from 'vitest';
+
+import type { PicloudClient, RealtimeEvent, Unsubscribe } from '../src/index.js';
+import { topicStore } from '../src/svelte/index.js';
+
+type Cb = (e: RealtimeEvent<unknown>) => void;
+
+describe('svelte topicStore', () => {
+  it('subscribes on first subscriber and unsubscribes on last', () => {
+    const unsubscribe = vi.fn();
+    const holder: { cb: Cb | null } = { cb: null };
+    const subscribe = vi.fn((_topic: string, cb: Cb): Unsubscribe => {
+      holder.cb = cb;
+      return unsubscribe as unknown as Unsubscribe;
+    });
+    const client = { subscribe } as unknown as PicloudClient;
+
+    const store = topicStore<{ x: number }>(client, 'chat');
+    // No SSE connection until someone subscribes (readable lifecycle).
+    expect(subscribe).not.toHaveBeenCalled();
+
+    let value: { x: number }[] = [];
+    const stop = store.subscribe((v) => (value = v));
+    expect(subscribe).toHaveBeenCalledTimes(1);
+
+    holder.cb?.({ topic: 'chat', message: { x: 1 }, published_at: 't' });
+    expect(value).toEqual([{ x: 1 }]);
+    expect(get(store)).toEqual([{ x: 1 }]);
+
+    stop();
+    expect(unsubscribe).toHaveBeenCalledTimes(1);
+  });
+});