Bug Report

Ionic version: [x] 4.x

Current behavior: When I swipe to open my side menu immediately after the app loaded, the app freezes. When I first tap the menu toggle button and then swipe, everything is fine.

Expected behavior: App doesn’t freeze.

Steps to reproduce: I was able to reproduce this in Chrome and sometimes I got to see an error (see stacktrace below). I’m even able to get the preview to freeze on the Ionic docs when I swipe just before the app’s first view is loaded: https://ionicframework.com/docs/api/menu

Related code: The stacktrace below led me to this file: core/src/components/menu/menu.tsx of this repo. The error comes from the loadAnimation function where this.menuInnerEl is undefined at that time:

const width = this.menuInnerEl!.offsetWidth;

Other information: Stacktrace:

zone.js:682 Unhandled Promise rejection: Cannot read property 'offsetWidth' of undefined ; Zone: <root> ; Task: Promise.then ; Value: TypeError: Cannot read property 'offsetWidth' of undefined
   at t.<anonymous> (n5wnzrch.entry.js:1)
   at step (tslib.js:97)
   at Object.next (tslib.js:78)
   at tslib.js:71
   at new ZoneAwarePromise (zone.js:910)
   at Module.__awaiter (tslib.js:67)
   at t.loadAnimation (n5wnzrch.entry.js:1)
   at t.onWillStart (n5wnzrch.entry.js:1)
   at onWillStart (n5wnzrch.entry.js:1)
   at m (chunk-f56eaea8.js:1) TypeError: Cannot read property 'offsetWidth' of undefined
   at t.<anonymous> (http://localhost:8100/70.js:44:4283)
   at step (http://localhost:8100/80.js:158:21)
   at Object.next (http://localhost:8100/80.js:139:51)
   at http://localhost:8100/80.js:132:69
   at new ZoneAwarePromise (http://localhost:8100/polyfills.js:3268:29)
   at Module.__awaiter (http://localhost:8100/80.js:128:10)
   at t.loadAnimation (http://localhost:8100/70.js:44:4107)
   at t.onWillStart (http://localhost:8100/70.js:44:5351)
   at onWillStart (http://localhost:8100/70.js:44:2193)
   at m (http://localhost:8100/common.js:84:6209)

Ionic info:

   ionic (Ionic CLI)             : 4.10.2 (/usr/local/lib/node_modules/ionic)
   Ionic Framework               : @ionic/angular 4.2.0
   @angular-devkit/build-angular : 0.12.4
   @angular-devkit/schematics    : 7.2.4
   @angular/cli                  : 7.2.4
   @ionic/angular-toolkit        : 1.5.0