fix: emit sync state on sync.{start,stop}

src/sync/sync-api.js

@@ -70,8 +70,7 @@ export class SyncApi extends TypedEmitter {
     this[kSyncState] = new SyncState({ coreManager, throttleMs })
     this[kSyncState].setMaxListeners(0)
     this[kSyncState].on('state', (namespaceSyncState) => {
-      const state = reduceSyncState(namespaceSyncState)
-      state.data.syncing = this.#dataSyncEnabled.has('local')
+      const state = this.#getState(namespaceSyncState)
       this.emit('sync-state', state)
     })
 
@@ -112,7 +111,15 @@ export class SyncApi extends TypedEmitter {
    * @returns {State}
    */
   getState() {
-    const state = reduceSyncState(this[kSyncState].getState())
+    return this.#getState(this[kSyncState].getState())
+  }
+
+  /**
+   * @param {import('./sync-state.js').State} namespaceSyncState
+   * @returns {State}
+   */
+  #getState(namespaceSyncState) {
+    const state = reduceSyncState(namespaceSyncState)
     state.data.syncing = this.#dataSyncEnabled.has('local')
     return state
   }
@@ -127,6 +134,7 @@ export class SyncApi extends TypedEmitter {
     for (const peerSyncController of this.#peerSyncControllers.values()) {
       peerSyncController.enableDataSync()
     }
+    this.emit('sync-state', this.getState())
   }
 
   /**
@@ -139,6 +147,7 @@ export class SyncApi extends TypedEmitter {
     for (const peerSyncController of this.#peerSyncControllers.values()) {
       peerSyncController.disableDataSync()
     }
+    this.emit('sync-state', this.getState())
   }
 
   /**

test-e2e/sync.js

@@ -1,5 +1,6 @@
 // @ts-check
 import { test } from 'brittle'
+import { setTimeout as delay } from 'timers/promises'
 import {
   connectPeers,
   createManagers,
@@ -259,3 +260,40 @@ test('no sync capabilities === no namespaces sync apart from auth', async (t) =>
 
   await Promise.all(projects.map((p) => p.close()))
 })
+
+test('Sync state emitted when starting and stopping sync', async function (t) {
+  const COUNT = 2
+  const managers = await createManagers(COUNT, t)
+  const [invitor, ...invitees] = managers
+  const projectId = await invitor.createProject({ name: 'Mapeo' })
+
+  const disconnect = connectPeers(managers, { discovery: false })
+
+  await invite({ invitor, invitees, projectId })
+
+  const projects = await Promise.all(
+    managers.map((m) => m.getProject(projectId))
+  )
+
+  const stateEvents = []
+
+  projects[0].$sync.on('sync-state', (state) => {
+    const timestamp = Date.now()
+    stateEvents.push({ state, timestamp })
+  })
+
+  projects[0].$sync.start()
+  t.ok(stateEvents.length === 1, 'sync-state event emitted after start')
+
+  await delay(500)
+
+  const eventCountBeforeStop = stateEvents.length
+  projects[0].$sync.stop()
+  t.ok(
+    stateEvents.length > eventCountBeforeStop,
+    'sync-state event emitted after stop'
+  )
+
+  await disconnect()
+  await Promise.all(projects.map((p) => p.close()))
+})