comply with strict and strictNullChecks (#11161)

src/Searching.ts

@@ -29,6 +29,7 @@ import { MatrixClient } from "matrix-js-sdk/src/matrix";
 
 import { ISearchArgs } from "./indexing/BaseEventIndexManager";
 import EventIndexPeg from "./indexing/EventIndexPeg";
+import { isNotUndefined } from "./Typeguards";
 
 const SEARCH_LIMIT = 10;
 
@@ -468,8 +469,8 @@ function combineEvents(
  */
 function combineResponses(
     previousSearchResult: ISeshatSearchResults,
-    localEvents: IResultRoomEvents,
-    serverEvents: IResultRoomEvents,
+    localEvents?: IResultRoomEvents,
+    serverEvents?: IResultRoomEvents,
 ): IResultRoomEvents {
     // Combine our events first.
     const response = combineEvents(previousSearchResult, localEvents, serverEvents);
@@ -480,11 +481,14 @@ function combineResponses(
     if (previousSearchResult.count) {
         response.count = previousSearchResult.count;
     } else {
-        response.count = localEvents.count + serverEvents.count;
+        const localEventCount = localEvents?.count ?? 0;
+        const serverEventCount = serverEvents?.count ?? 0;
+
+        response.count = localEventCount + serverEventCount;
     }
 
     // Update our next batch tokens for the given search sources.
-    if (localEvents) {
+    if (localEvents && isNotUndefined(previousSearchResult.seshatQuery)) {
         previousSearchResult.seshatQuery.next_batch = localEvents.next_batch;
     }
     if (serverEvents) {
@@ -505,7 +509,11 @@ function combineResponses(
     // pagination request.
     //
     // Provide a fake next batch token for that case.
-    if (!response.next_batch && previousSearchResult.cachedEvents.length > 0) {
+    if (
+        !response.next_batch &&
+        isNotUndefined(previousSearchResult.cachedEvents) &&
+        previousSearchResult.cachedEvents.length > 0
+    ) {
         response.next_batch = "cached";
     }
 
@@ -565,16 +573,12 @@ async function combinedPagination(
 
     // Fetch events from the server if we have a token for it and if it's the
     // local indexes turn or the local index has exhausted its results.
-    if (searchResult.serverSideNextBatch && (oldestEventFrom === "local" || !searchArgs.next_batch)) {
+    if (searchResult.serverSideNextBatch && (oldestEventFrom === "local" || !searchArgs?.next_batch)) {
         const body = { body: searchResult._query!, next_batch: searchResult.serverSideNextBatch };
         serverSideResult = await client.search(body);
     }
 
-    let serverEvents: IResultRoomEvents | undefined;
-
-    if (serverSideResult) {
-        serverEvents = serverSideResult.search_categories.room_events;
-    }
+    const serverEvents: IResultRoomEvents | undefined = serverSideResult?.search_categories.room_events;
 
     // Combine our events.
     const combinedResult = combineResponses(searchResult, localResult, serverEvents);