History API

Summary

`history.pushState`/`replaceState` and the `popstate` event let JavaScript manipulate the browser's URL and back/forward history without a full page reload — the foundation of client-side routing. This enables single-page applications to keep URLs meaningful and navigable while updating views without performing a full document navigation.

• 1Use `pushState` to change the URL without reloading the page. Verify the behavior with realistic data and handle the failure or empty state as well.
• 2Listen for `popstate` to react to the browser's back/forward buttons. Validate your understanding by applying it in a small practical example.
• 3Understand this is exactly what React Router/Next.js use under the hood.