fix(event): clear residual js listeners (#8916 ) (#8930)

* fix clear residual listeners tauri-apps#8916

* Comment out `println` on successful removal of `js_listeners`

* follow review changes.

* remvoe uneeded result

* Update fix-clear-residual-listeners.md

.changes/fix-clear-residual-listeners.md

@@ -0,0 +1,5 @@
+---
+"tauri": patch:bug
+---
+
+Clear JS event listeneres on page load, which fixes zombie listeners when the page reloads.

core/tauri/src/event/listener.rs

@@ -271,6 +271,12 @@ impl Listeners {
     }
   }
 
+  pub(crate) fn unlisten_all_js(&self, webview_label: &str) {
+    let inner_listeners = self.inner.as_ref();
+    let mut js_listeners = inner_listeners.js_event_listeners.lock().unwrap();
+    js_listeners.remove(webview_label);
+  }
+
   pub(crate) fn has_js_listener<F: Fn(&EventTarget) -> bool>(
     &self,
     event: &str,

core/tauri/src/webview/mod.rs

@@ -568,17 +568,20 @@ tauri::Builder::default()
       }));
     }
 
-    if let Some(on_page_load_handler) = self.on_page_load_handler.take() {
-      let label = pending.label.clone();
-      let manager = manager.manager_owned();
-      pending
-        .on_page_load_handler
-        .replace(Box::new(move |url, event| {
-          if let Some(w) = manager.get_webview(&label) {
-            on_page_load_handler(w, PageLoadPayload { url: &url, event });
+    let label_ = pending.label.clone();
+    let manager_ = manager.manager_owned();
+    pending
+      .on_page_load_handler
+      .replace(Box::new(move |url, event| {
+        if let Some(w) = manager_.get_webview(&label_) {
+          if let PageLoadEvent::Finished = event {
+            w.unlisten_all_js();
           }
-        }));
-    }
+          if let Some(handler) = self.on_page_load_handler.as_ref() {
+            handler(w, PageLoadPayload { url: &url, event });
+          }
+        }
+      }));
 
     manager.manager().webview.prepare_webview(
       manager,
@@ -1317,6 +1320,12 @@ fn main() {
     Ok(())
   }
 
+  /// Unregister all JS event listeners.
+  pub(crate) fn unlisten_all_js(&self) {
+    let listeners = self.manager().listeners();
+    listeners.unlisten_all_js(self.label());
+  }
+
   pub(crate) fn emit_js(&self, emit_args: &EmitArgs, target: &EventTarget) -> crate::Result<()> {
     self.eval(&crate::event::emit_js_script(
       self.manager().listeners().function_name(),