Microsoft Edge Sleeping Tabs: Does it suspend or wipe HTML5 localStorage for inactive Web Apps?

Hi everyone,

I am optimizing the frontend state management for a daily browser puzzle I recently launched called Hang Five.

The game is entirely client-side and relies heavily on HTML5 localStorage to save a user's daily progress, remaining lives, and their win streak. Because it is a daily puzzle, many users open the site in the morning, make a few guesses, and leave the tab open in the background to finish later in the evening.

I noticed that Microsoft Edge's "Sleeping Tabs" feature aggressively puts inactive tabs to sleep to save memory.

My questions for the Edge engineering community:

When Edge puts a tab to sleep, does it freeze the JavaScript execution completely, or just throttle the requestAnimationFrame/timers?

More importantly, when the tab "wakes up," is there any known risk of the localStorage state failing to sync properly if the browser cleared memory cache while it was asleep?

I want to make sure Edge users don't lose their puzzle progress if they leave the tab dormant for 8+ hours. Should I implement a custom service worker to handle state recovery, or is standard localStorage safe against the Sleeping Tabs feature?

Thanks in advance for the clarification!