egui_web: log panics using console.error

egui_web/CHANGELOG.md

@@ -7,8 +7,9 @@ All notable changes to the `egui_web` integration will be noted in this file.
 * The default painter is now glow instead of WebGL ([#1020](https://github.com/emilk/egui/pull/1020)).
 * Made the WebGL painter opt-in ([#1020](https://github.com/emilk/egui/pull/1020)).
 * Fixed glow failure on Chromium ([#1092](https://github.com/emilk/egui/pull/1092)).
-* Shift-scroll will now result in horizontal scrolling on all platforms ([#1136](https://github.com/emilk/egui/pull/1136)).
+* Shift-scroll will now result in horizontal scrolling ([#1136](https://github.com/emilk/egui/pull/1136)).
 * Updated `epi::IntegrationInfo::web_location_hash` on `hashchange` event ([#1140](https://github.com/emilk/egui/pull/1140)).
+* Panics will now be logged using `console.error`.
 
 
 ## 0.16.0 - 2021-12-29

egui_web/Cargo.toml

@@ -34,6 +34,7 @@ egui_glow = { version = "0.16.0",path = "../egui_glow", default-features = false
 epi = { version = "0.16.0", path = "../epi" }
 
 bytemuck = "1.7"
+console_error_panic_hook = "0.1.6"
 js-sys = "0.3"
 ron = { version = "0.7", optional = true }
 serde = { version = "1", optional = true }

egui_web/src/backend.rs

@@ -281,6 +281,9 @@ impl AppRunner {
 /// Install event listeners to register different input events
 /// and start running the given app.
 pub fn start(canvas_id: &str, app: Box<dyn epi::App>) -> Result<AppRunnerRef, JsValue> {
+    // Make sure panics are logged using `console.error`.
+    console_error_panic_hook::set_once();
+
     let mut runner = AppRunner::new(canvas_id, app)?;
     runner.warm_up()?;
     start_runner(runner)