shell: add debug output

Author: jelly

pkg/shell/state.tsx

@@ -192,6 +192,7 @@ export class ShellState extends EventEmitter<ShellStateEvents> {
 
         const old_onerror = window.onerror;
         window.onerror = (msg, url, line) => {
+            console.log("onerror", msg, line);
             // Errors with url == "" are not logged apparently, so let's
             // not show the "Oops" for them either.
             if (url != "") {