fix(event): let once event return `EventId`, close #8912 (#8914)

* fix(event): let once event return EventId

* Update .changes/core-once-event-return-event-id.md

.changes/core-once-event-return-event-id.md

@@ -0,0 +1,5 @@
+---
+'tauri': 'patch:enhance'
+---
+
+Return an id when using from `Manager::once_any`, `App::once`, `Window::once`, `Webview::once`, `WebviewWindow::once` and `fs::Scope::once`.

core/tauri/src/app.rs

@@ -845,7 +845,7 @@ macro_rules! shared_app_impl {
       /// Listen to an event on this app only once.
       ///
       /// See [`Self::listen`] for more information.
-      pub fn once<F>(&self, event: impl Into<String>, handler: F)
+      pub fn once<F>(&self, event: impl Into<String>, handler: F) -> EventId
       where
         F: FnOnce(Event) + Send + 'static,
       {

core/tauri/src/event/listener.rs

@@ -159,7 +159,7 @@ impl Listeners {
     event: String,
     target: EventTarget,
     handler: F,
-  ) {
+  ) -> EventId {
     let self_ = self.clone();
     let handler = Cell::new(Some(handler));
 
@@ -170,7 +170,7 @@ impl Listeners {
         .expect("attempted to call handler more than once");
       handler(event);
       self_.unlisten(id);
-    });
+    })
   }
 
   /// Removes an event listener.

core/tauri/src/lib.rs

@@ -655,7 +655,7 @@ pub trait Manager<R: Runtime>: sealed::ManagerBase<R> {
   /// Listens once to an emitted event to any [target](EventTarget) .
   ///
   /// See [`Self::listen_any`] for more information.
-  fn once_any<F>(&self, event: impl Into<String>, handler: F)
+  fn once_any<F>(&self, event: impl Into<String>, handler: F) -> EventId
   where
     F: FnOnce(Event) + Send + 'static,
   {

core/tauri/src/manager/mod.rs

@@ -469,7 +469,7 @@ impl<R: Runtime> AppManager<R> {
     event: String,
     target: EventTarget,
     handler: F,
-  ) {
+  ) -> EventId {
     assert_event_name_is_valid(&event);
     self.listeners().once(event, target, handler)
   }

core/tauri/src/scope/fs.rs

@@ -201,7 +201,7 @@ impl Scope {
   }
 
   /// Listen to an event on this scope and immediately unlisten.
-  pub fn once<F: FnOnce(&Event) + Send + 'static>(&self, f: F) {
+  pub fn once<F: FnOnce(&Event) + Send + 'static>(&self, f: F) -> ScopeEventId {
     let listerners = self.event_listeners.clone();
     let handler = std::cell::Cell::new(Some(f));
     let id = self.next_event_id();
@@ -212,6 +212,7 @@ impl Scope {
         .expect("attempted to call handler more than once");
       handler(event)
     });
+    id
   }
 
   /// Removes an event listener on this scope.

core/tauri/src/webview/mod.rs

@@ -1460,7 +1460,7 @@ tauri::Builder::default()
   /// Listen to an event on this webview only once.
   ///
   /// See [`Self::listen`] for more information.
-  pub fn once<F>(&self, event: impl Into<String>, handler: F)
+  pub fn once<F>(&self, event: impl Into<String>, handler: F) -> EventId
   where
     F: FnOnce(Event) + Send + 'static,
   {

core/tauri/src/webview/webview_window.rs

@@ -1766,7 +1766,7 @@ tauri::Builder::default()
   /// Listen to an event on this window webview only once.
   ///
   /// See [`Self::listen`] for more information.
-  pub fn once<F>(&self, event: impl Into<String>, handler: F)
+  pub fn once<F>(&self, event: impl Into<String>, handler: F) -> EventId
   where
     F: FnOnce(Event) + Send + 'static,
   {

core/tauri/src/window/mod.rs

@@ -1992,7 +1992,7 @@ tauri::Builder::default()
   /// Listen to an event on this window only once.
   ///
   /// See [`Self::listen`] for more information.
-  pub fn once<F>(&self, event: impl Into<String>, handler: F)
+  pub fn once<F>(&self, event: impl Into<String>, handler: F) -> EventId
   where
     F: FnOnce(Event) + Send + 'static,
   {