fix(react): outlet will not clear in react 18 with hot reload

[sean-perkins]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
  • Some docs updates need to be made in the ionic-docs repo, in a separate PR. See the contributing guide for details.
• Build (npm run build) was run locally and any changes were pushed
• Lint (npm run lint) has passed locally and any fixes were made for failures

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

In React 18, components are mounted/unmounted in dev build to check for side effects. The StackManager implementation has logic to clear the outlet when it is unmounted. Unfortunately this implementation of clearing the outlet has an inner setTimeout that will resolve 500ms after it is invoked.

This results in:

• Page Mounted
• Page Unmounted
  • clearOutlet / setTimeout
• Page Remounted
  • setTimeout resolves and clears the page
• Page is blank

This is only a problem in React 18 & in development mode. Noticeable with hot reloading, as any changes will clear the view.

Issue URL: #25507

What is the new behavior?

• Returns the timeout to the implementation layer so that we can cancel the operation when the component is re-mounted in dev-mode (created tech debt task in backlog to investigate removing timeout in React Router v6 work)
• React 18 and hot reload will no longer clear the page/outlet when the page remounts

Does this introduce a breaking change?

• Yes
• No

Other information

Dev-build: 6.2.1-dev.11659463817.1943a7f4 ✅ (need to install for both @ionic/react and @ionic/react-router)