From ba9d1e446c800def83e63844ca5b0c15dd75c0cd Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
Date: Sat, 20 Aug 2022 10:04:12 +0200
Subject: [PATCH] Simplify interface

---
 eframe/src/web/backend.rs |  7 ++++---
 egui_demo_app/src/lib.rs  | 17 ++---------------
 2 files changed, 6 insertions(+), 18 deletions(-)

diff --git a/eframe/src/web/backend.rs b/eframe/src/web/backend.rs
index 7849ea72..f231172a 100644
--- a/eframe/src/web/backend.rs
+++ b/eframe/src/web/backend.rs
@@ -35,7 +35,7 @@ impl WebInput {
 
 // ----------------------------------------------------------------------------
 
-use std::{any::Any, sync::atomic::Ordering::SeqCst};
+use std::sync::atomic::Ordering::SeqCst;
 
 /// Stores when to do the next repaint.
 pub struct NeedRepaint(Mutex<f64>);
@@ -265,8 +265,9 @@ impl AppRunner {
         &self.egui_ctx
     }
 
-    pub fn get_app_mut(&mut self) -> &mut dyn Any {
-        self.app.as_any_mut()
+    /// Get mutable access to the concrete [`App`] we enclose.
+    pub fn app_mut<ConreteApp: 'static + crate::App>(&mut self) -> &mut ConreteApp {
+        self.app.as_any_mut().downcast_mut::<ConreteApp>().unwrap()
     }
 
     pub fn auto_save(&mut self) {
diff --git a/egui_demo_app/src/lib.rs b/egui_demo_app/src/lib.rs
index b00cad8e..aafd53ae 100644
--- a/egui_demo_app/src/lib.rs
+++ b/egui_demo_app/src/lib.rs
@@ -32,7 +32,6 @@ pub struct WebHandle {
 #[wasm_bindgen]
 impl WebHandle {
     #[wasm_bindgen]
-    #[cfg(target_arch = "wasm32")]
     pub fn stop_web(&self) -> Result<(), wasm_bindgen::JsValue> {
         let mut app = self.handle.lock();
         let res = app.destroy();
@@ -44,22 +43,10 @@ impl WebHandle {
         res
     }
 
-    // helper for mutating original app from javascript
-    fn with_app<F>(&mut self, func: F) -> ()
-    where
-        F: Fn(&mut WrapApp) -> (),
-    {
-        let mut runner_ref = self.handle.lock();
-        let app_ref = runner_ref.get_app_mut();
-        let app = app_ref.downcast_mut::<WrapApp>().unwrap();
-        func(app);
-    }
-
     #[wasm_bindgen]
     pub fn set_some_content_from_javasript(&mut self, _some_data: &str) {
-        self.with_app(|_app| {
-            // app.data = some_data;
-        });
+        let _app = self.handle.lock().app_mut::<WrapApp>();
+        // _app.data = some_data;
     }
 }