__TSR_index is NaN, resulting in invalid history notifications (subscriber)

[wolkyura]

Which project does this relate to?

Router

Describe the bug

I tried subscribing to router history changes to track back/forward navigation, but it's not working for me. When using the browser’s back/forward buttons, I get this action - { type: 'GO', index: NaN }.

I looked into history/src/index.ts and found that the history index is stored in __TSR_index, and in my case, it's NaN (see screenshot).

Your Example Website or App

https://stackblitz.com/edit/github-gn1q23iq?file=src%2Froutes%2F__root.tsx

Steps to Reproduce the Bug or Issue

1. Navigate to About page
2. Navigate back using browser back button

Expected behavior

I'd expect BACK action type being sent when using browser back button

Screenshots or Videos

Platform

• macOS
• Chrome
• Version: 134.0.6998.166

Additional context

No response

[schiller-manuel]

cc @ferretwithaberet