fix: review fix

Author: lkn

src/ava.ts

@@ -268,6 +268,10 @@ export class AVA extends EventEmitter {
   async visualize(analysisResult: AnalysisResponse): Promise<VisualizeResponse | null> {
     const { data, query } = analysisResult;
 
+    if (!hasData(data)) {
+      return null;
+    }
+
     try {
       // Format analysis data info from the analysis result data
       const analysisDataInfoStr = Array.isArray(data)
@@ -282,7 +286,7 @@ export class AVA extends EventEmitter {
         detail: chartType ?? 'No visualization needed',
       });
 
-      if (!chartType || !hasData(data)) {
+      if (!chartType) {
         return null;
       }
 

src/events.ts

@@ -12,7 +12,13 @@ export class EventEmitter {
   }
 
   off(event: string, handler: Handler): this {
-    this._events.get(event)?.delete(handler);
+    const handlers = this._events.get(event);
+    if (handlers) {
+      handlers.delete(handler);
+      if (handlers.size === 0) {
+        this._events.delete(event);
+      }
+    }
     return this;
   }