Ns Page Navigation Lifecycle

Page navigation lifecycle and the backstack

For one forward navigation followed by back, a page fires exactly this sequence:

navigatingTo → loaded → navigatedTo   ...   navigatingFrom → unloaded → navigatedFrom

What is true at each step:

• navigatingTo — earliest hook; args.context (the NavigationEntry.context) is available. Set bindingContext here.
• loaded — the view tree exists and native views are attached, but Frame.topmost().currentPage is NOT this page yet. Don't read "the current page" here expecting yourself.
• navigatedTo — navigation committed; currentPage is now this page. Start animations, timers, subscriptions here.
• navigatingFrom / unloaded / navigatedFrom — note unloaded fires BEFORE navigatedFrom. Teardown that needs the native view must happen by unloaded; navigatedFrom is last and runs on an already-unloaded page.
• After a back-pop the page is fully torn down: parent, frame and the native context are null, isLoaded is false. Never cache a popped Page for reuse.
• page.navigationContext is cleared on back navigation — read what you need from it before leaving, or copy it onto your view model.

import { EventData, NavigatedData, Page } from '@nativescript/core';

export function navigatingTo(args: NavigatedData) {
  const page = <Page>args.object;
  if (args.isBackNavigation) return;         // returning — state already built
  page.bindingContext = createViewModel(args.context);
}

Navigating with context

Frame.topmost().navigate({
  moduleName: 'views/detail/detail-page',
  context: { id: item.id },                  // arrives as args.context / page.navigationContext
  backstackVisible: true,                    // default; false = skipped on back
  clearHistory: false,
});

• clearHistory: true empties the backstack; the outgoing page fires only navigatingFrom/navigatedFrom (no unload pair queued behind a back button that no longer exists) and frame.backStack.length becomes 0.
• backstackVisible: false entries still construct and navigate normally — the page factory runs — they are only skipped when going back.
• frame.goBack() when canGoBack() is false is a safe no-op. After N forward navigations where the last was backstackVisible: false, you get N−1 successful goBack()s.
• Jump multiple screens back with frame.goBack(frame.backStack[0]) (pass the target entry).
• isBackNavigation on intermediate skipped pages is still forward-shaped on the from-events — don't branch teardown on it; branch setup on it in navigatingTo (the classic guard above).

Frames

• Frame.topmost() follows whichever frame navigated most recently — inside a TabView it's the selected tab's frame, not the app root (see ns-tabview-lazy-loading).
• The Frame itself re-emits only navigatingTo/navigatedTo — never the From pair. Listen on the Page for those.

Where work belongs

Verified 2026-08 against @nativescript/core 9.1.0-rc.3: event order, currentPage timing, context clearing, teardown state and canGoBack behavior are asserted in apps/automated/src/ui/page/page-tests-common.ts, ui/frame/frame-tests-common.ts and navigation/navigation-tests.ts; not re-run standalone.