Fix TypeError in timeline messaging when thread has no participants

When a message thread has no participants with role FROM in the threadParticipantsByThreadId map, the lookup returns undefined which is passed to extractParticipantSummary -> filterActiveParticipants, causing "Cannot read properties of undefined (reading 'filter')". Add nullish coalescing fallback to empty array in formatThreads, and add early return guard in extractParticipantSummary for empty participant arrays. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-02-19 15:51:19 +00:00
2 changed files with 17 additions and 1 deletions
@@ -13,6 +13,22 @@ export const extractParticipantSummary = (
  const activeMessageParticipants =
    filterActiveParticipants(messageParticipants);

+  if (activeMessageParticipants.length === 0) {
+    return {
+      firstParticipant: {
+        personId: null,
+        workspaceMemberId: null,
+        firstName: '',
+        lastName: '',
+        displayName: '',
+        avatarUrl: '',
+        handle: '',
+      },
+      lastTwoParticipants: [],
+      participantCount: 0,
+    };
+  }
+
  const firstParticipant = formatThreadParticipant(
    activeMessageParticipants[0],
  );
@@ -35,7 +35,7 @@ export const formatThreads = (
        visibility === MessageChannelVisibility.SHARE_EVERYTHING
          ? thread.lastMessageBody
          : FIELD_RESTRICTED_ADDITIONAL_PERMISSIONS_REQUIRED,
-      ...extractParticipantSummary(threadParticipantsByThreadId[thread.id]),
+      ...extractParticipantSummary(threadParticipantsByThreadId[thread.id] ?? []),
      visibility,
      read: true,
    };