GSAP React Router

mount → initial state → intro → settled → outro → end state → unmount

Mount and unmount belong to React; animation owns the five phases between them. React Router has no leave hook: hold navigation with a blocker or intercept it before it starts. Parameter changes can reuse the route element.

Keep the requested look and existing project conventions. Add GSAP/plugins only as needed; do not replace the chosen animation library unless asked.

This skill decides when motion runs. For what moves, and for a feel such as premium or playful, also load the animaxxing skill when it is installed: its recipes and its guide to finding the vibe plug into this lifecycle.

Start with the project

Read repository instructions, existing animation, layouts, navigation, CSS, accessibility conventions, and checks. Then:

1. Confirm React Router 7 or later and its mode. Framework mode has react-router.config.ts, routes.ts, root.tsx, and HydratedRouter in entry.client.tsx. Data mode has createBrowserRouter and RouterProvider. Declarative mode has BrowserRouter and no loaders, no useNavigation, and no blocker. A Remix 2 app uses the same hooks from @remix-run/react; say so and map the names.
2. Read the installed version from node_modules/react-router/package.json. The package ships its docs/, CHANGELOG.md, and .d.ts files in dist/; prefer them over memory. Version gates: useBlocker (6.19), viewTransition and useViewTransitionState (6.27), Link mask and useTransitions (7.15), middleware (7.9 behind future.v8_middleware, always on in 8). Version 8 is ESM-only, needs React 19.2, and drops react-router-dom: RouterProvider and HydratedRouter come from react-router/dom.
3. In framework mode check ssr and prerender in react-router.config.ts. Server-rendered and prerendered pages paint HTML before hydration. ssr: false ships an index.html holding only the root route and its HydrateFallback, so route content renders after hydration and needs no pre-paint rule. Data and declarative mode without server rendering are the same.

Choose the engine

In data/framework mode, use Link, Form, or navigate with viewTransition for snapshot morphs or page crossfades. Use GSAP for live-DOM outros that gate navigation, interruptible sequences, split text, or scroll-linked motion. One engine per element; see combining engines.

Read only what you need

• Invisible entrances, failed initialization, indexing, and first-load performance: Initialization and recovery, plus the framework integration.
• The blocker outro, transition-aware links, the lock, pending state, back and forward, the swap gap, scroll, focus, View Transitions: React Router navigation.
• Modes and their hooks, route reuse versus remount, layouts and <Outlet>, SSR and SPA mode first paint, streaming, fetchers, modal routes: Route lifetime.
• The five phases, GSAP setup, React lifecycle, show and hide, layout stability, scroll, text, plugins: Lifecycle implementation.
• Lenis, ScrollSmoother, or eased page scrolling across routes: Smooth scrolling, plus the React Router integration.
• Curtains, first-visit preloaders, and shared-element morphs: Transition archetypes, plus where they live under React Router.
• Touch, viewport changes, and device budgets: Devices and input.
• Tauri, Electron, or Wails desktop shells: Desktop webviews.
• Before calling work done: Verification.

Install the official GSAP skills alongside this repository. Load gsap-core for API details and gsap-react for component setup only as needed.

Rules

• Preserve invisible intros on successful setup; recover the current incoming owner on failure. Follow the initialization contract before adding hiding rules.
• GSAP runs only in the browser. Framework mode evaluates route modules on the server, so keep GSAP calls inside useGSAP or effects and registration in a .client side-effect module. Import gsap and useGSAP from their packages: .client exports are undefined during SSR. Scope selectors. Clean up every tween, trigger, split, and listener.
• Reserve final geometry with normal CSS and a stable wrapper; overlap outgoing/incoming content without doubling layout space.
• Mount, then set initial values, then paint. Server HTML paints before hydration: hide intro targets only under a root attribute set by an inline script in the root Layout, only during the initial phase, with a no-JavaScript path.
• Clear temporary styles at settled. Use will-change only while animating; this overrides gsap-performance's static hint.
• Use capability queries for device tiers. Touch states release; controls work without hover.
• Keep outgoing routes mounted and visible through outro and end state. The router unmounts the old route when the new one commits, so hold the commit: useBlocker and proceed() from the end callback, or prevent the Link default and navigate after the outro.
• Never block or outro a POP. Back and forward get initial state and intro only, after scroll restoration.
• A navigation to the same route with new params reuses the element. Key the outlet on location.pathname, or run the lifecycle again from a pathname dependency against DOM that already holds settled values.
• Loaders run after proceed(), so the end state waits for data. Prefetch on intent and cover the route container until the incoming targets are prepared.
• A fetcher is not a navigation. Do not treat fetcher.state as a page transition.
• One engine per element. A named view transition and a GSAP tween on the same node fight.
• Keep native link behavior: modified clicks, target, reloadDocument, external URLs, prefetch, NavLink state, focus, scroll, and no-JavaScript readability.
• Reduced motion reaches the same settled state and still fires every completion callback, including the one that calls proceed().
• Define interruption and rapid-click behavior; completion must release navigation waits exactly once.
• Verify in a real browser when practical. Use a production build for route, config, dependency, or release changes.