feat(Index.tsx): implement abort controller for text correction to prevent race conditions

src/pages/Index.tsx

@@ -124,6 +124,7 @@ $current`);
   const [correctedContent, setCorrectedContent] = useState('');
   const [previousNoteCorrectedContent, setPreviousNoteCorrectedContent] = useState('');
   const [correctionTimeout, setCorrectionTimeout] = useState<NodeJS.Timeout>();
+  const [correctionAbortController, setCorrectionAbortController] = useState<AbortController | null>(null);
 
   const { resolvedTheme, setTheme } = useTheme();
 
@@ -338,20 +339,38 @@ $current`);
 
   // Debounced text correction for previous note
   const debouncedCorrectPreviousNote = (content: string) => {
+    // Cancel any pending correction request
+    if (correctionAbortController) {
+      try {
+        correctionAbortController.abort();
+      } catch (error) {
+        // Ignore abort errors - the controller might already be aborted
+      }
+    }
+
     if (correctionTimeout) {
       clearTimeout(correctionTimeout);
     }
 
+    // Create new AbortController for this request
+    const abortController = new AbortController();
+    setCorrectionAbortController(abortController);
+
     const timeout = setTimeout(async () => {
       if (content.trim()) {
         try {
           addDebugInfo('Correcting previous note text...');
-          const corrected = await correctText(content);
+          const corrected = await correctText(content, abortController);
           setPreviousNoteCorrectedContent(corrected);
         } catch (error) {
+          if (error instanceof Error && error.name === 'AbortError') {
+            addDebugInfo('Previous note correction cancelled');
+            return; // Don't set empty content for aborted requests
+          } else {
             console.error('Previous note text correction failed:', error);
             setPreviousNoteCorrectedContent('');
           }
+        }
       } else {
         setPreviousNoteCorrectedContent('');
       }
@@ -361,7 +380,7 @@ $current`);
   };
 
   // Correct text using Ollama
-  const correctText = async (content: string): Promise<string> => {
+  const correctText = async (content: string, abortController?: AbortController): Promise<string> => {
     try {
       const response = await fetchWithTiming(`${ollamaEndpoint}/api/generate`, {
         method: 'POST',
@@ -387,6 +406,7 @@ ${content}`,
           keep_alive: ollamaKeepAlive,
           temperature: 0.1,
         }),
+        signal: abortController?.signal,
       }, 'Correct Text');
 
       if (!response.ok) {
@@ -1169,6 +1189,16 @@ ${content}`,
     const reversedDelta = -delta;
     const newIndex = Math.max(0, Math.min(currentNoteIndex + reversedDelta, noteCache.length - 1));
     if (newIndex !== currentNoteIndex && noteCache[newIndex]) {
+      // Cancel any pending correction request before changing notes
+      if (correctionAbortController) {
+        try {
+          correctionAbortController.abort();
+        } catch (error) {
+          // Ignore abort errors - the controller might already be aborted
+        }
+        setCorrectionAbortController(null);
+      }
+      
       setCurrentNoteIndex(newIndex);
       setPreviousNote(noteCache[newIndex]);
       setIsPreviousNoteModified(false);
@@ -1355,6 +1385,14 @@ ${content}`,
       if (correctionTimeout) {
         clearTimeout(correctionTimeout);
       }
+      // Cancel any pending correction request on cleanup
+      if (correctionAbortController) {
+        try {
+          correctionAbortController.abort();
+        } catch (error) {
+          // Ignore abort errors - the controller might already be aborted
+        }
+      }
     };
   }, [currentNote, previousNote, scratchPad, isPreviousNoteModified, isSearchOpen, isGotoOpen, isCleanupOpen]);