wip: YJs provider on models

package.json

@@ -59,8 +59,10 @@
   "dependencies": {
     "@types/lodash": "^4.14.195",
     "ably": "^1.2.41",
+    "js-base64": "^3.7.5",
     "lodash": "^4.17.21",
     "pino": "^8.14.1",
-    "rxjs": "^7.8.1"
+    "rxjs": "^7.8.1",
+    "yjs": "^13.6.8"
   }
 }

src/AblyProvider.test.ts

@@ -0,0 +1,151 @@
+import { fromUint8Array, toUint8Array } from 'js-base64';
+import * as Y from 'yjs';
+import { Realtime, Types as AblyTypes } from 'ably/promises';
+import { it, describe, expect, afterEach, vi, beforeEach } from 'vitest';
+import AblyProvider from './AblyProvider';
+import { Subject } from 'rxjs';
+import { customMessage } from './utilities/test/messages';
+
+vi.mock('ably/promises');
+
+interface ProviderTestContext {
+  ably: AblyTypes.RealtimePromise;
+  sendChannel: any;
+  receiveChannel: any;
+}
+
+describe('AblyProvider', () => {
+  beforeEach<ProviderTestContext>((context) => {
+    const ably = new Realtime({});
+    context.ably = ably;
+    const sendChannel = {
+      on: vi.fn<any, any>(),
+      publish: vi.fn<any, any>(),
+      attach: vi.fn<any, any>(),
+      detach: vi.fn<any, any>(),
+    };
+    const receiveChannel = {
+      on: vi.fn<any, any>(),
+      attach: vi.fn<any, any>(),
+      detach: vi.fn<any, any>(),
+      subscribe: vi.fn<any, any>(),
+      history: vi.fn<any, any>(),
+    };
+    receiveChannel.history = vi.fn<any, any>(
+      async (): Promise<Partial<AblyTypes.PaginatedResult<Types.Message>>> => ({
+        items: [],
+        hasNext: () => false,
+      }),
+    );
+
+    context.sendChannel = sendChannel;
+    context.receiveChannel = receiveChannel;
+
+    context.ably.channels.get = vi.fn<any, any>((name: string) => {
+      if (name.startsWith('send')) {
+        return context.sendChannel;
+      }
+
+      return context.receiveChannel;
+    });
+    context.ably.channels.release = vi.fn<any, any>();
+
+    ably.connection.whenState = vi.fn<[AblyTypes.ConnectionState], Promise<AblyTypes.ConnectionStateChange>>(
+      async () => {
+        return {
+          current: 'connected',
+          previous: 'initialized',
+        };
+      },
+    );
+
+    context.sendChannel = sendChannel;
+    context.receiveChannel = receiveChannel;
+  });
+
+  it<ProviderTestContext>('sends updates', (context) => {
+    const clientId = 'abc123';
+    context.ably.clientId = clientId;
+
+    const sendChannel = context.sendChannel;
+
+    const yDoc = new Y.Doc();
+
+    const provider = new AblyProvider(yDoc, {
+      ably: context.ably,
+      sendChannel: 'sendChannel',
+      receiveChannel: 'receiveChannel',
+      bootstrap: exampleBootstrapFunction,
+    });
+
+    yDoc.getMap('mymap').set('field', 'value');
+
+    expect(sendChannel.publish).toHaveBeenCalledTimes(1);
+    const update = sendChannel.publish.mock.calls[0][1].update;
+    expect(sendChannel.publish).toHaveBeenCalledWith('update', { update: update, origin: clientId });
+
+    const yUpdate = toUint8Array(update);
+    const got = new Y.Doc();
+    Y.applyUpdate(got, yUpdate);
+    expect(got.getMap('mymap').get('field')).toEqual('value');
+  });
+
+  it<ProviderTestContext>('applies updates', async (context) => {
+    const clientId = 'foobarbaz';
+    context.ably.clientId = clientId;
+    const yDoc = new Y.Doc();
+    const remoteDoc = new Y.Doc();
+
+    let updates = new Subject<AblyTypes.Message>();
+    context.receiveChannel.subscribe = vi.fn<any, any>(async (callback) => {
+      updates.subscribe((update) => {
+        callback(update);
+      });
+      return {
+        current: 'attached',
+        previous: 'attaching',
+        resumed: false,
+        hasBacklog: false,
+      };
+    });
+
+    // When a change is applied to the 'remoteDoc', that change
+    // becomes a channel message on the 'updates' subject, and applied
+    // to the local YDoc.
+    remoteDoc.on('update', (update, origin) => {
+      updates.next(customMessage('1', 'update', JSON.stringify({ update: fromUint8Array(update), origin: origin })));
+    });
+
+    // Assert the local YDoc does not contain the map field
+    expect(yDoc.getMap('mymap').get('field')).toBeUndefined();
+
+    const provider = new AblyProvider(yDoc, {
+      ably: context.ably,
+      sendChannel: 'sendChannel',
+      receiveChannel: 'receiveChannel',
+      bootstrap: exampleBootstrapFunction,
+    });
+    await new Promise<void>((resolve) => {
+      provider.whenState('ready', '', () => {
+        resolve();
+      });
+    });
+    const localUpdateReceived = new Promise((resolve) => {
+      yDoc.on('update', (update, origin) => {
+        resolve(origin);
+      });
+    });
+
+    // Change the 'remoteDoc', update should be propagated to local YDoc
+    remoteDoc.getMap('mymap').set('field', 'value');
+
+    // Wait for local update to be received
+    const origin = await localUpdateReceived;
+    expect(origin).toEqual('server');
+    expect(yDoc.getMap('mymap').get('field')).toEqual('value');
+  });
+});
+
+const exampleBootstrapFunction = async (doc: Y.Doc) => {
+  return { serverStateVector: Uint8Array.of(), serverUpdate: Uint8Array.of() };
+};