Clearing router outlet logs errors

[danielwiehl]

Describe the bug

When clearing a router outlet, wrong origin errors are logged to the console:

Failed to execute 'postMessage' on 'DOMWindow': The target origin provided does not match the recipient window's origin

To Reproduce

Steps to reproduce the behavior:

1. Open Testing App of the SCION Microfrontend Platform: https://scion-microfrontend-platform-testing-app.vercel.app/
2. Open the DevTools (DevTools toggle button in the upper right corner)
3. Load the router page into the left outlet: https://scion-microfrontend-platform-testing-app1-v1-0-0-rc-12.vercel.app/#/outlet-router
   3.1. Enter 'devtools' into the outlet field
   3.2. Click 'Navigate'
4. See the errors logged to the console: Failed to execute 'postMessage' on 'DOMWindow': The target origin provided ('https://scion-microfrontend-platform-devtools-v1-0-0-rc-12.vercel.app') does not match the recipient window's origin ('https://scion-microfrontend-platform-testing-app.vercel.app').

Analysis

• The outlet is cleared as expected.
• Errors are only logged for outlets embedded directly in the host app
• When unloading the microfrontend, the microfrontend unregisters from active messaging subscriptions in the broker (MicrofrontendPlatformStopper -> unload -> MicrofrontendPlatform.destroy). The broker then replies with acknowledgments. In the meantime, the outlet has been unloaded and replaced with about:blank, causing the errors due to the origin mismatch.

Expected behavior

No errors are logged to the console.

Environment

Please complete the following information:

SCION Microfrontend Platform version: 1.0.0-rc.12
Browser: Chrome 108.0.5359.125