Replace update functions with a merge function

src/Errors.ts

@@ -1,7 +1,5 @@
 import toString from 'lodash/toString';
 
-import type { UpdateTargets } from './UpdatesRegistry.js';
-
 export function toError(err: any) {
   return err instanceof Error || err instanceof AggregateError ? err : new Error(toString(err));
 }
@@ -19,25 +17,3 @@ export class RegistrationError extends Error {
     this.name = 'RegistrationError';
   }
 }
-
-/**
- * Represents an error that occurs when a given update function specified by
- * the target is not registered on the model.
- *
- * @internal
- * @extends {RegistrationError}
- */
-export class UpdateRegistrationError extends RegistrationError {
-  constructor(targets: Partial<UpdateTargets>) {
-    let message = 'update not registered';
-    if (targets.channel && !targets.event) {
-      message = `update for channel '${targets.channel}' not registered`;
-    } else if (!targets.channel && targets.event) {
-      message = `update for event '${targets.event}' not registered`;
-    } else if (targets.channel && targets.event) {
-      message = `update for event '${targets.event}' on channel '${targets.channel}' not registered`;
-    }
-    super(message);
-    this.name = 'UpdateRegistrationError';
-  }
-}

src/Model.discontinuity.test.ts

@@ -36,8 +36,9 @@ describe('Model', () => {
     const logger = pino({ level: 'silent' });
     context.ably = ably;
     context.logger = logger;
+    context.channelName = 'models:myModel:events';
   });
-  it<ModelTestContext>('handles discontinuity with resync', async ({ ably, logger }) => {
+  it<ModelTestContext>('handles discontinuity with resync', async ({ channelName, ably, logger }) => {
     const channel = ably.channels.get('foo');
     let suspendChannel: (...args: any[]) => void = () => {
       throw new Error('suspended not defined');
@@ -58,11 +59,11 @@ describe('Model', () => {
     let counter = 0;
 
     const sync = vi.fn(async () => `${counter++}`);
-    const model = new Model<string, {}>('test', { ably, logger });
-    const update1 = vi.fn(async (state, event) => {
+    const model = new Model<string, {}>('test', { ably, channelName, logger });
+    const mergeFn = vi.fn(async (state, event) => {
       return event.data;
     });
-    await model.$register({ $sync: sync, $update: { s1: { testEvent: update1 } } });
+    await model.$register({ $sync: sync, $merge: mergeFn });
 
     expect(sync).toHaveBeenCalledOnce();