Make realtime presence functionality tree-shakable

We move it into a tree-shakable RealtimePresence module.

Resolves #1375.

scripts/moduleReport.js

@@ -1,7 +1,7 @@
 const esbuild = require('esbuild');
 
 // List of all modules accepted in ModulesMap
-const moduleNames = ['Rest', 'Crypto', 'MsgPack'];
+const moduleNames = ['Rest', 'Crypto', 'MsgPack', 'RealtimePresence'];
 
 // List of all free-standing functions exported by the library along with the
 // ModulesMap entries that we expect them to transitively import

src/common/lib/client/baserealtime.ts

@@ -10,17 +10,20 @@ import { ChannelOptions } from '../../types/channel';
 import ClientOptions from '../../types/ClientOptions';
 import * as API from '../../../../ably';
 import { ModulesMap } from './modulesmap';
+import RealtimePresence from './realtimepresence';
 
 /**
  `BaseRealtime` is an export of the tree-shakable version of the SDK, and acts as the base class for the `BaseRealtime` class exported by the non tree-shakable version.
  */
 class BaseRealtime extends BaseClient {
+  readonly _RealtimePresence: typeof RealtimePresence | null;
   _channels: any;
   connection: Connection;
 
   constructor(options: ClientOptions, modules: ModulesMap) {
     super(options, modules);
     Logger.logAction(Logger.LOG_MINOR, 'Realtime()', '');
+    this._RealtimePresence = modules.RealtimePresence ?? null;
     this.connection = new Connection(this, this.options);
     this._channels = new Channels(this);
     if (options.autoConnect !== false) this.connect();

src/common/lib/client/channel.ts

@@ -50,7 +50,10 @@ class Channel extends EventEmitter {
   client: BaseClient;
   name: string;
   basePath: string;
-  presence: Presence;
+  private _presence: Presence;
+  get presence(): Presence {
+    return this._presence;
+  }
   channelOptions: ChannelOptions;
 
   constructor(client: BaseClient, name: string, channelOptions?: ChannelOptions) {
@@ -59,7 +62,7 @@ class Channel extends EventEmitter {
     this.client = client;
     this.name = name;
     this.basePath = '/channels/' + encodeURIComponent(name);
-    this.presence = new Presence(this);
+    this._presence = new Presence(this);
     this.channelOptions = normaliseChannelOptions(client._Crypto ?? null, channelOptions);
   }
 

src/common/lib/client/defaultrealtime.ts

@@ -7,6 +7,7 @@ import ProtocolMessage from '../types/protocolmessage';
 import Platform from 'common/platform';
 import { DefaultMessage } from '../types/defaultmessage';
 import { MsgPack } from 'common/types/msgpack';
+import RealtimePresence from './realtimepresence';
 
 /**
  `DefaultRealtime` is the class that the non tree-shakable version of the SDK exports as `Realtime`. It ensures that this version of the SDK includes all of the functionality which is optionally available in the tree-shakable version.
@@ -18,7 +19,7 @@ export class DefaultRealtime extends BaseRealtime {
       throw new Error('Expected DefaultRealtime._MsgPack to have been set');
     }
 
-    super(options, { ...allCommonModules, Crypto: DefaultRealtime.Crypto ?? undefined, MsgPack });
+    super(options, { ...allCommonModules, Crypto: DefaultRealtime.Crypto ?? undefined, MsgPack, RealtimePresence });
   }
 
   static Utils = Utils;

src/common/lib/client/modulesmap.ts

@@ -1,11 +1,13 @@
 import { Rest } from './rest';
 import { IUntypedCryptoStatic } from '../../types/ICryptoStatic';
 import { MsgPack } from 'common/types/msgpack';
+import RealtimePresence from './realtimepresence';
 
 export interface ModulesMap {
   Rest?: typeof Rest;
   Crypto?: IUntypedCryptoStatic;
   MsgPack?: MsgPack;
+  RealtimePresence?: typeof RealtimePresence;
 }
 
 export const allCommonModules: ModulesMap = { Rest };

src/common/lib/client/realtimechannel.ts

@@ -50,7 +50,13 @@ function validateChannelOptions(options?: API.Types.ChannelOptions) {
 
 class RealtimeChannel extends Channel {
   realtime: BaseRealtime;
-  presence: RealtimePresence;
+  private _realtimePresence: RealtimePresence | null;
+  get presence(): RealtimePresence {
+    if (!this._realtimePresence) {
+      Utils.throwMissingModuleError('RealtimePresence');
+    }
+    return this._realtimePresence;
+  }
   connectionManager: ConnectionManager;
   state: API.Types.ChannelState;
   subscriptions: EventEmitter;
@@ -84,7 +90,7 @@ class RealtimeChannel extends Channel {
     super(realtime, name, options);
     Logger.logAction(Logger.LOG_MINOR, 'RealtimeChannel()', 'started; name = ' + name);
     this.realtime = realtime;
-    this.presence = new RealtimePresence(this);
+    this._realtimePresence = realtime._RealtimePresence ? new realtime._RealtimePresence(this) : null;
     this.connectionManager = realtime.connection.connectionManager;
     this.state = 'initialized';
     this.subscriptions = new EventEmitter();
@@ -591,7 +597,9 @@ class RealtimeChannel extends Channel {
         if (this.state === 'attached') {
           if (!resumed) {
             /* On a loss of continuity, the presence set needs to be re-synced */
-            this.presence.onAttached(hasPresence);
+            if (this._realtimePresence) {
+              this._realtimePresence.onAttached(hasPresence);
+            }
           }
           const change = new ChannelStateChange(this.state, this.state, resumed, message.error);
           this._allChannelChanges.emit('update', change);
@@ -649,7 +657,9 @@ class RealtimeChannel extends Channel {
             Logger.logAction(Logger.LOG_ERROR, 'RealtimeChannel.processMessage()', (e as Error).toString());
           }
         }
-        this.presence.setPresence(presence, isSync, syncChannelSerial as any);
+        if (this._realtimePresence) {
+          this._realtimePresence.setPresence(presence, isSync, syncChannelSerial as any);
+        }
         break;
       }
       case actions.MESSAGE: {
@@ -784,7 +794,9 @@ class RealtimeChannel extends Channel {
     if (state === this.state) {
       return;
     }
-    this.presence.actOnChannelState(state, hasPresence, reason);
+    if (this._realtimePresence) {
+      this._realtimePresence.actOnChannelState(state, hasPresence, reason);
+    }
     if (state === 'suspended' && this.connectionManager.state.sendEvents) {
       this.startRetryTimer();
     } else {

src/platform/web/modules.ts

@@ -41,5 +41,6 @@ if (Platform.Config.noUpgrade) {
 export * from './modules/crypto';
 export * from './modules/message';
 export * from './modules/msgpack';
+export * from './modules/realtimepresence';
 export { Rest } from '../../common/lib/client/rest';
 export { BaseRest, BaseRealtime };

src/platform/web/modules/realtimepresence.ts

@@ -0,0 +1 @@
+export { default as RealtimePresence } from '../../../common/lib/client/realtimepresence';

test/browser/modules.test.js

@@ -10,6 +10,7 @@ import {
   decodeEncryptedMessages,
   Crypto,
   MsgPack,
+  RealtimePresence,
 } from '../../build/modules/index.js';
 
 describe('browser/modules', function () {
@@ -20,11 +21,13 @@ describe('browser/modules', function () {
   let testResourcesPath;
   let loadTestData;
   let testMessageEquality;
+  let randomString;
 
   before((done) => {
     ablyClientOptions = window.ablyHelpers.ablyClientOptions;
     testResourcesPath = window.ablyHelpers.testResourcesPath;
     testMessageEquality = window.ablyHelpers.testMessageEquality;
+    randomString = window.ablyHelpers.randomString;
 
     loadTestData = async (dataPath) => {
       return new Promise((resolve, reject) => {
@@ -315,4 +318,35 @@ describe('browser/modules', function () {
       });
     });
   });
+
+  describe('RealtimePresence', () => {
+    describe('BaseRealtime without RealtimePresence', () => {
+      it('throws an error when attempting to access the `presence` property', () => {
+        const client = new BaseRealtime(ablyClientOptions(), {});
+        const channel = client.channels.get('channel');
+
+        expect(() => channel.presence).to.throw();
+      });
+    });
+
+    describe('BaseRealtime with RealtimePresence', () => {
+      it('offers realtime presence functionality', async () => {
+        const rxChannel = new BaseRealtime(ablyClientOptions(), { RealtimePresence }).channels.get('channel');
+        const txClientId = randomString();
+        const txChannel = new BaseRealtime(ablyClientOptions({ clientId: txClientId }), {
+          RealtimePresence,
+        }).channels.get('channel');
+
+        let resolveRxPresenceMessagePromise;
+        const rxPresenceMessagePromise = new Promise((resolve, reject) => {
+          resolveRxPresenceMessagePromise = resolve;
+        });
+        await rxChannel.presence.subscribe('enter', resolveRxPresenceMessagePromise);
+        await txChannel.presence.enter();
+
+        const rxPresenceMessage = await rxPresenceMessagePromise;
+        expect(rxPresenceMessage.clientId).to.equal(txClientId);
+      });
+    });
+  });
 });

test/common/modules/shared_helper.js

@@ -245,6 +245,10 @@ define([
     expect(json1 === json2, 'JSON data contents mismatch.').to.be.ok;
   }
 
+  function randomString() {
+    return Math.random().toString().slice(2);
+  }
+
   var exports = {
     setupApp: testAppModule.setup,
     tearDownApp: testAppModule.tearDown,
@@ -278,6 +282,7 @@ define([
     arrFilter: arrFilter,
     whenPromiseSettles: whenPromiseSettles,
     testMessageEquality: testMessageEquality,
+    randomString: randomString,
   };
 
   if (typeof window !== 'undefined') {

test/realtime/channel.test.js

@@ -10,11 +10,7 @@ define(['ably', 'shared_helper', 'async', 'chai'], function (Ably, helper, async
   var createPM = Ably.Realtime.ProtocolMessage.fromDeserialized;
   var testOnAllTransports = helper.testOnAllTransports;
   var whenPromiseSettles = helper.whenPromiseSettles;
-
-  /* Helpers */
-  function randomString() {
-    return Math.random().toString().slice(2);
-  }
+  var randomString = helper.randomString;
 
   function checkCanSubscribe(channel, testChannel) {
     return function (callback) {