Was the page navigated to using back or forward button?

window.performance.getEntriesByType("navigation")[0].type === "back_forward";

This is how to detect if a page was loaded because the user navigated via back or forward buttons.

Possible values:

• back_forward if the navigation happened because of a back or forward navigation
• navigate if the navigation happened because of a regular navigation event (like clicking a link).
• reload after reloading the page
• prerender if the navigation has happened during a prerender hint

See PerformanceNavigationTiming.type on MDN