[fix] yjs presence (#1603)

This PR:
- updates the yjs example to include user presence
- tweaks the `createPresenceStateDerivation` API
- fix a "double update" bug caused by re-syncing local changes
- fix connection bugs

### Change Type

- [x] `minor` — New feature

apps/examples/src/yjs/YjsExample.tsx

@@ -1,6 +1,7 @@
-import { Tldraw } from '@tldraw/tldraw'
+import { Tldraw, useEditor } from '@tldraw/tldraw'
 import '@tldraw/tldraw/editor.css'
 import '@tldraw/tldraw/ui.css'
+import { track } from 'signia-react'
 import { useYjsStore } from './useYjsStore'
 
 const HOST_URL =
@@ -8,14 +9,41 @@ const HOST_URL =
 
 export default function YjsExample() {
 	const store = useYjsStore({
-		roomId: 'example',
+		roomId: 'example6',
 		hostUrl: HOST_URL,
-		version: 3,
 	})
 
 	return (
 		<div className="tldraw__editor">
-			<Tldraw autoFocus store={store} />
+			<Tldraw autoFocus store={store} shareZone={<NameEditor />} />
 		</div>
 	)
 }
+
+const NameEditor = track(() => {
+	const editor = useEditor()
+
+	const { color, name } = editor.user
+
+	return (
+		<div style={{ pointerEvents: 'all', display: 'flex' }}>
+			<input
+				type="color"
+				value={color}
+				onChange={(e) => {
+					editor.user.updateUserPreferences({
+						color: e.currentTarget.value,
+					})
+				}}
+			/>
+			<input
+				value={name}
+				onChange={(e) => {
+					editor.user.updateUserPreferences({
+						name: e.currentTarget.value,
+					})
+				}}
+			/>
+		</div>
+	)
+})

apps/examples/src/yjs/useYjsStore.ts

@@ -1,47 +1,74 @@
 import {
 	DocumentRecordType,
+	InstancePresenceRecordType,
 	PageRecordType,
 	TLDocument,
 	TLInstancePresence,
 	TLPageId,
 	TLRecord,
 	TLStoreWithStatus,
-	TLUserPreferences,
 	createPresenceStateDerivation,
 	createTLStore,
 	defaultShapes,
-	getFreshUserPreferences,
+	getUserPreferences,
 } from '@tldraw/tldraw'
-import { debounce } from '@tldraw/utils'
-import { useEffect, useState } from 'react'
-import { atom, react } from 'signia'
+import { useEffect, useMemo, useState } from 'react'
+import { computed, react, transact } from 'signia'
 import { WebsocketProvider } from 'y-websocket'
 import * as Y from 'yjs'
 
-const doc = new Y.Doc({ gc: true })
-
 export function useYjsStore({
 	roomId = 'example',
-	version = 1,
 	hostUrl = process.env.NODE_ENV === 'development' ? 'ws://localhost:1234' : 'wss://demos.yjs.dev',
 }: Partial<{ hostUrl: string; roomId: string; version: number }>) {
+	const [store] = useState(() => createTLStore({ shapes: defaultShapes }))
 	const [storeWithStatus, setStoreWithStatus] = useState<TLStoreWithStatus>({ status: 'loading' })
 
+	const { doc, room, yRecords } = useMemo(() => {
+		const doc = new Y.Doc({ gc: true })
+		return {
+			doc,
+			room: new WebsocketProvider(hostUrl, roomId, doc, { connect: true }),
+			yRecords: doc.getMap<TLRecord>(`tl_${roomId}`),
+		}
+	}, [hostUrl, roomId])
+
 	useEffect(() => {
-		const yRecords = doc.getMap<TLRecord>(`tl_${roomId}_${version}`)
-
-		const room = new WebsocketProvider(hostUrl, roomId, doc, { connect: true })
-		const userId = room.awareness.clientID.toString()
-
 		const unsubs: (() => void)[] = []
-		const store = createTLStore({ shapes: defaultShapes })
 
-		room.on('status', (connected: boolean) => {
-			if (connected) {
-				/* ----------------- Initialization ----------------- */
+		// We'll use this flag to prevent repeating subscriptions if our connection drops and reconnects.
+		let didConnect = false
 
+		room.on('status', ({ status }: { status: 'connecting' | 'disconnected' | 'connected' }) => {
+			// If we're disconnected, set the store status to 'synced-remote' and the connection status to 'offline'
+			if (status === 'connecting' || status === 'disconnected') {
+				setStoreWithStatus({
+					store,
+					status: 'synced-remote',
+					connectionStatus: 'offline',
+				})
+				return
+			}
+
+			if (status !== 'connected') return
+
+			if (didConnect) {
+				setStoreWithStatus({
+					store,
+					status: 'synced-remote',
+					connectionStatus: 'online',
+				})
+				return
+			}
+
+			// Ok, we're connecting for the first time. Let's get started!
+			didConnect = true
+
+			// Initialize the store with the yjs doc records—or, if the yjs doc
+			// is empty, initialize the yjs doc with the default store records.
 			if (yRecords.size === 0) {
-					doc.transact(() => {
+				// Create the initial store records
+				transact(() => {
 					store.clear()
 					store.put([
 						DocumentRecordType.create({
@@ -53,12 +80,20 @@ export function useYjsStore({
 							index: 'a1',
 						}),
 					])
-						store.allRecords().forEach((record) => {
-							yRecords.set(record.id, record)
 				})
+
+				// Sync the store records to the yjs doc
+				doc.transact(() => {
+					for (const record of store.allRecords()) {
+						yRecords.set(record.id, record)
+					}
 				})
 			} else {
-					store.put([...yRecords.values()], 'initialize')
+				// Replace the store records with the yjs doc records
+				transact(() => {
+					store.clear()
+					store.put([...yRecords.values()])
+				})
 			}
 
 			/* -------------------- Document -------------------- */
@@ -66,7 +101,7 @@ export function useYjsStore({
 			// Sync store changes to the yjs doc
 			unsubs.push(
 				store.listen(
-						({ changes }) => {
+					function syncStoreChangesToYjsDoc({ changes }) {
 						doc.transact(() => {
 							Object.values(changes.added).forEach((record) => {
 								yRecords.set(record.id, record)
@@ -81,15 +116,18 @@ export function useYjsStore({
 							})
 						})
 					},
-						{ source: 'user', scope: 'document' }
+					{ source: 'user', scope: 'document' } // only sync user's document changes
 				)
 			)
 
 			// Sync the yjs doc changes to the store
-				const handleChange = ([event]: Y.YEvent<any>[]) => {
-					const toDelete: TLRecord['id'][] = []
+			const handleChange = (events: Y.YEvent<any>[], transaction: Y.Transaction) => {
+				if (transaction.local) return
+
+				const toRemove: TLRecord['id'][] = []
 				const toPut: TLRecord[] = []
 
+				events.forEach((event) => {
 					event.changes.keys.forEach((change, id) => {
 						switch (change.action) {
 							case 'add':
@@ -98,15 +136,17 @@ export function useYjsStore({
 								break
 							}
 							case 'delete': {
-								toDelete.push(id as TLRecord['id'])
+								toRemove.push(id as TLRecord['id'])
 								break
 							}
 						}
 					})
+				})
 
+				// put / remove the records in the store
 				store.mergeRemoteChanges(() => {
-						store.remove(toDelete)
-						store.put(toPut)
+					if (toRemove.length) store.remove(toRemove)
+					if (toPut.length) store.put(toPut)
 				})
 			}
 
@@ -115,92 +155,58 @@ export function useYjsStore({
 
 			/* -------------------- Awareness ------------------- */
 
-				// Get the persisted user preferences or use the defaults
-
-				let userPreferences: TLUserPreferences = {
-					...getFreshUserPreferences(),
-					id: userId,
-				}
-
-				const persistedUserPreferences = localStorage.getItem(`tldraw-presence-${version}`)
-				if (persistedUserPreferences !== null) {
-					try {
-						userPreferences = JSON.parse(persistedUserPreferences) as TLUserPreferences
-					} catch (e: any) {
-						// Something went wrong, persist the defaults instead
-						localStorage.setItem(`tldraw-presence-${version}`, JSON.stringify(userPreferences))
-					}
-				}
-
-				const debouncedPersist = debounce((presence: TLInstancePresence) => {
-					const preferences: TLUserPreferences = {
-						...userPreferences,
-						name: presence.userName,
-						color: presence.color,
-					}
-
-					localStorage.setItem(`tldraw-presence-${version}`, JSON.stringify(preferences))
-				}, 1000)
-
 			// Create the instance presence derivation
-				const userPreferencesSignal = atom<TLUserPreferences>('user preferences', userPreferences)
-				const presenceDerivation = createPresenceStateDerivation(userPreferencesSignal)(store)
+			const yClientId = room.awareness.clientID.toString()
+			const presenceId = InstancePresenceRecordType.createId(yClientId)
+			const userPreferencesComputed = computed('ok', () => getUserPreferences())
+			const presenceDerivation = createPresenceStateDerivation(
+				userPreferencesComputed,
+				presenceId
+			)(store)
+
+			// Set our initial presence from the derivation's current value
 			room.awareness.setLocalStateField('presence', presenceDerivation.value)
 
-				// Sync the instance presence changes to yjs awareness
+			// When the derivation change, sync presence to to yjs awareness
 			unsubs.push(
 				react('when presence changes', () => {
 					const presence = presenceDerivation.value
-						if (presence && presence.userId === userId) {
+					requestAnimationFrame(() => {
 						room.awareness.setLocalStateField('presence', presence)
-							debouncedPersist(presence)
-						}
+					})
 				})
 			)
 
 			// Sync yjs awareness changes to the store
-				const handleUpdate = ({
-					added,
-					updated,
-					removed,
-				}: {
-					added: number[]
-					updated: number[]
-					removed: number[]
-				}) => {
-					const states = room.awareness.getStates()
+			const handleUpdate = (update: { added: number[]; updated: number[]; removed: number[] }) => {
+				const states = room.awareness.getStates() as Map<number, { presence: TLInstancePresence }>
 
+				const toRemove: TLInstancePresence['id'][] = []
+				const toPut: TLInstancePresence[] = []
+
+				// Connect records to put / remove
+				for (const clientId of update.added) {
+					const state = states.get(clientId)
+					if (state?.presence && state.presence.id !== presenceId) {
+						toPut.push(state.presence)
+					}
+				}
+
+				for (const clientId of update.updated) {
+					const state = states.get(clientId)
+					if (state?.presence && state.presence.id !== presenceId) {
+						toPut.push(state.presence)
+					}
+				}
+
+				for (const clientId of update.removed) {
+					toRemove.push(InstancePresenceRecordType.createId(clientId.toString()))
+				}
+
+				// put / remove the records in the store
 				store.mergeRemoteChanges(() => {
-						added.forEach((id) => {
-							const state = states.get(id) as { presence: TLInstancePresence }
-							if (state.presence) {
-								if (state.presence.userId !== userId) {
-									store.put([state.presence])
-								}
-							}
-						})
-
-						updated.forEach((id) => {
-							const state = states.get(id) as { presence: TLInstancePresence }
-							if (state.presence) {
-								if (state.presence.userId !== userId) {
-									store.put([state.presence])
-								}
-							}
-						})
-
-						if (removed.length) {
-							const allRecords = store.allRecords()
-
-							removed.forEach((id) => {
-								const stringId = id.toString()
-								const recordsToRemove = allRecords
-									.filter((record) => 'userId' in record && record.userId === stringId)
-									.map((record) => record.id)
-
-								store.remove(recordsToRemove)
-							})
-						}
+					if (toRemove.length) store.remove(toRemove)
+					if (toPut.length) store.put(toPut)
 				})
 			}
 
@@ -208,26 +214,18 @@ export function useYjsStore({
 			unsubs.push(() => room.awareness.off('update', handleUpdate))
 
 			// And we're done!
-
 			setStoreWithStatus({
 				store,
 				status: 'synced-remote',
 				connectionStatus: 'online',
 			})
-			} else {
-				setStoreWithStatus({
-					store,
-					status: 'synced-remote',
-					connectionStatus: 'offline',
-				})
-			}
 		})
 
 		return () => {
 			unsubs.forEach((fn) => fn())
 			unsubs.length = 0
 		}
-	}, [hostUrl, roomId, version])
+	}, [room, doc, store, yRecords])
 
 	return storeWithStatus
 }

packages/editor/api-report.md

@@ -243,6 +243,13 @@ export function createSessionStateSnapshotSignal(store: TLStore): Signal<null |
 // @public
 export function createTLStore({ initialData, defaultName, ...rest }: TLStoreOptions): TLStore;
 
+// @public (undocumented)
+export function createTLUser(opts?: {
+    derivePresenceState?: ((store: TLStore) => Signal<null | TLInstancePresence>) | undefined;
+    userPreferences?: Signal<TLUserPreferences, unknown> | undefined;
+    setUserPreferences?: ((userPreferences: TLUserPreferences) => void) | undefined;
+}): TLUser;
+
 // @public (undocumented)
 export function dataTransferItemAsString(item: DataTransferItem): Promise<string>;
 

packages/editor/src/index.ts

@@ -45,6 +45,7 @@ export {
 	type TLStoreEventInfo,
 	type TLStoreOptions,
 } from './lib/config/createTLStore'
+export { createTLUser } from './lib/config/createTLUser'
 export { coreShapes, defaultShapes } from './lib/config/defaultShapes'
 export { defaultTools } from './lib/config/defaultTools'
 export { defineShape, type TLShapeInfo } from './lib/config/defineShape'

packages/editor/src/lib/editor/Editor.ts

@@ -1674,7 +1674,10 @@ export class Editor extends EventEmitter<TLEventMap> {
 	 * @public
 	 */
 	get currentPage(): TLPage {
-		return this.getPageById(this.currentPageId)!
+		const page = this.getPageById(this.currentPageId)
+		if (!page)
+			throw Error(`No current page (id ${this.currentPageId}, ${this.pages.length} pages))`)
+		return page
 	}
 
 	/**

packages/editor/src/lib/editor/managers/UserPreferencesManager.ts

@@ -11,6 +11,10 @@ export class UserPreferencesManager {
 		})
 	}
 
+	get userPreferences() {
+		return this.user.userPreferences
+	}
+
 	get isDarkMode() {
 		return this.user.userPreferences.value.isDarkMode
 	}

packages/tlschema/api-report.md

@@ -125,7 +125,7 @@ export const createPresenceStateDerivation: ($user: Signal<{
     id: string;
     color: string;
     name: string;
-}>) => (store: TLStore) => Signal<null | TLInstancePresence>;
+}>, instanceId?: TLInstancePresence['id']) => (store: TLStore) => Signal<null | TLInstancePresence>;
 
 // @public (undocumented)
 export function createShapeId(id?: string): TLShapeId;

packages/tlschema/src/createPresenceStateDerivation.ts

@@ -8,7 +8,10 @@ import { InstancePresenceRecordType, TLInstancePresence } from './records/TLPres
 
 /** @public */
 export const createPresenceStateDerivation =
-	($user: Signal<{ id: string; color: string; name: string }>) =>
+	(
+		$user: Signal<{ id: string; color: string; name: string }>,
+		instanceId?: TLInstancePresence['id']
+	) =>
 	(store: TLStore): Signal<TLInstancePresence | null> => {
 		return computed('instancePresence', () => {
 			const instance = store.get(TLINSTANCE_ID)
@@ -21,7 +24,7 @@ export const createPresenceStateDerivation =
 			}
 
 			return InstancePresenceRecordType.create({
-				id: InstancePresenceRecordType.createId(store.id),
+				id: instanceId ?? InstancePresenceRecordType.createId(store.id),
 				selectedIds: pageState.selectedIds,
 				brush: instance.brush,
 				scribble: instance.scribble,