fix: do not re-highlight when already processing highlights

src/content/ContentScript.ts

@@ -68,7 +68,7 @@ export class ContentScript {
   }
 
   private setupScrollHandler(): void {
-    const debouncedProcess = DOMUtils.debounce(() => this.processHighlights(), 300);
+    const debouncedProcess = DOMUtils.debounce(() => this.processHighlights(), CONSTANTS.DEBOUNCE_DELAY);
     window.addEventListener('scroll', debouncedProcess);
   }
 

src/content/HighlightEngine.ts

@@ -5,25 +5,31 @@ export class HighlightEngine {
   private styleSheet: CSSStyleSheet | null = null;
   private wordStyleMap = new Map<string, string>();
   private observer: MutationObserver;
+  private isHighlighting = false;
 
   constructor(private onUpdate: () => void) {
     this.observer = new MutationObserver(DOMUtils.debounce((mutations: MutationRecord[]) => {
-      const hasRelevantChanges = mutations.some((mutation: MutationRecord) => {
+      if (this.isHighlighting) return;
+
+      const hasContentChanges = mutations.some((mutation: MutationRecord) => {
+        if (mutation.type !== 'childList') return false;
+
         if (mutation.target instanceof Element && mutation.target.hasAttribute('data-gh')) {
           return false;
         }
-        const addedNodes = Array.from(mutation.addedNodes);
-        const removedNodes = Array.from(mutation.removedNodes);
-        const isOurChange = [...addedNodes, ...removedNodes].some(node => 
-          node instanceof Element && (node.hasAttribute('data-gh') || node.querySelector('[data-gh]'))
-        );
-        return !isOurChange;
+
+        const allNodes = [...Array.from(mutation.addedNodes), ...Array.from(mutation.removedNodes)];
+        return allNodes.some(node => {
+          if (node.nodeType === Node.TEXT_NODE) return true;
+          if (node instanceof Element && !node.hasAttribute('data-gh')) return true;
+          return false;
+        });
       });
 
-      if (hasRelevantChanges) {
-        onUpdate();
+      if (hasContentChanges) {
+        this.onUpdate();
       }
-    }, 300));
+    }, CONSTANTS.DEBOUNCE_DELAY));
   }
 
   private initializeStyleSheet(): void {
@@ -109,6 +115,9 @@ export class HighlightEngine {
   }
 
   highlight(lists: HighlightList[], matchCase: boolean, matchWhole: boolean): void {
+    if (this.isHighlighting) return;
+    this.isHighlighting = true;
+
     this.observer.disconnect();
 
     this.clearHighlightsInternal();
@@ -116,6 +125,7 @@ export class HighlightEngine {
     const activeWords = this.extractActiveWords(lists);
     if (activeWords.length === 0) {
       this.startObserving();
+      this.isHighlighting = false;
       return;
     }
 
@@ -155,6 +165,7 @@ export class HighlightEngine {
     }
 
     this.startObserving();
+    this.isHighlighting = false;
   }
 
   private clearHighlightsInternal(): void {
@@ -182,8 +193,6 @@ export class HighlightEngine {
     this.observer.observe(document.body, {
       childList: true,
       subtree: true,
-      characterData: true,
-      // Don't observe attribute changes to avoid triggering on our own style changes
       attributes: false
     });
   }