keep memory of the last string in the queue

qjs_wrapper.c

@@ -265,7 +265,7 @@ static JSValue js_drone_init(JSContext *ctx, JSValueConst thisVal,
     return JS_UNDEFINED;
 }
 
-static JSValue readDroneDataStr(JSContext *ctx, StrQueue *pQueue)
+static JSValue readDroneDataStr(JSContext *ctx, StrQueue *pQueue, bool keepAtLeastAnElement)
 {
     JSValue res;
     struct strNode *current;
@@ -273,8 +273,15 @@ static JSValue readDroneDataStr(JSContext *ctx, StrQueue *pQueue)
     current = pQueue->head;
     if (current != NULL) {
         res = JS_NewString(ctx, current->str);
-        pQueue->head = current->next == NULL ? (pQueue->tail = NULL) : current->next;
-        delete_str_node(current);
+        if (current->next != NULL) {
+            pQueue->head = current->next;
+            delete_str_node(current);
+        } else {
+            if (!keepAtLeastAnElement) {
+                pQueue->head = (pQueue->tail = NULL);
+                delete_str_node(current);
+            }
+        }
     } else {
         res = JS_NewString(ctx, "");
     }
@@ -304,9 +311,9 @@ static JSValue js_drone_get(JSContext *ctx, JSValueConst thisVal, int magic)
         case 7:
             return JS_NewFloat64(ctx, s->climbRate);
         case 8:
-            return readDroneDataStr(ctx, &(s->receiveMessageQueue));
+            return readDroneDataStr(ctx, &(s->receiveMessageQueue), true);
         case 9:
-            return readDroneDataStr(ctx, &(s->receiveLogQueue));
+            return readDroneDataStr(ctx, &(s->receiveLogQueue), false);
         case 10:
             return JS_NewInt64(ctx, s->timestamp);
         default: