git:20260526.876125d to v1.0.0

+ description: Guide for implementing smooth, native-feeling animations using React's View Transition API (`<ViewTransition>` component, `addTransitionType`, and CSS view transition pseudo-elements). Use this skill whenever the user wants to add page transitions, animate route changes, create shared element animations, animate enter/exit of components, animate list reorder, implement directional (forward/back) navigation animations, or integrate view transitions in Next.js. Also use when the user mentions view transitions, `startViewTransition`, `ViewTransition`, transition types, or asks about animating between UI states in React without third-party animation libraries.

+ license: MIT

+ author: vercel

+ version: "1.0.0"

+ # React View Transitions

+ Animate between UI states using the browser's native `document.startViewTransition`. Declare _what_ with `<ViewTransition>`, trigger _when_ with `startTransition` / `useDeferredValue` / `Suspense`, control _how_ with CSS classes. Unsupported browsers skip animations gracefully.

+ ## When to Animate

+ Every `<ViewTransition>` should communicate a spatial relationship or continuity. If you can't articulate what it communicates, don't add it.

+ Implement **all** applicable patterns from this list, in this order:

+ | Priority | Pattern | What it communicates |

+ | -------- | ---------------------------------- | -------------------------------- |

+ | 1 | **Shared element** (`name`) | "Same thing — going deeper" |

+ | 2 | **Suspense reveal** | "Data loaded" |

+ | 3 | **List identity** (per-item `key`) | "Same items, new arrangement" |

+ | 4 | **State change** (`enter`/`exit`) | "Something appeared/disappeared" |

+ | 5 | **Route change** (layout-level) | "Going to a new place" |

+ This is an implementation order, not a "pick one" list. Implement every pattern that fits the app. Only skip a pattern if the app has no use case for it.

+ ### Choosing Animation Style

+ | Context | Animation | Why |

+ | --------------------------------------- | -------------------------------------------------- | ---------------------------- |

+ | Hierarchical navigation (list → detail) | Type-keyed `nav-forward` / `nav-back` | Communicates spatial depth |

+ | Lateral navigation (tab-to-tab) | Bare `<ViewTransition>` (fade) or `default="none"` | No depth to communicate |

+ | Suspense reveal | `enter`/`exit` string props | Content arriving |

+ | Revalidation / background refresh | `default="none"` | Silent — no animation needed |

+ Reserve directional slides for hierarchical navigation (list → detail) and ordered sequences (prev/next photo, carousel, paginated results). For ordered sequences, the direction communicates position: "next" slides from right, "previous" from left. Lateral/unordered navigation (tab-to-tab) should not use directional slides — it falsely implies spatial depth.

+ ---

+ ## Availability

+ - **Next.js:** Do **not** install `react@canary` — the App Router already bundles React canary internally. `ViewTransition` works out of the box. `npm ls react` may show a stable-looking version; this is expected.

+ - **Without Next.js:** Install `react@canary react-dom@canary` (`ViewTransition` is not in stable React).

+ - Browser support: Chromium 111+, Firefox 144+, Safari 18.2+. Graceful degradation on unsupported browsers.

+ ---

+ ## Implementation Workflow

+ When adding view transitions to an existing app, **follow `references/implementation.md` step by step.** Start with the audit — do not skip it. Copy the CSS recipes from `references/css-recipes.md` into the global stylesheet — do not write your own animation CSS.

+ ---

+ ## Core Concepts

+ ### The `<ViewTransition>` Component

+ ```jsx

+ import { ViewTransition } from "react";

+ <ViewTransition>

+ <Component />

+ </ViewTransition>;

+ ```

+ React auto-assigns a unique `view-transition-name` and calls `document.startViewTransition` behind the scenes. Never call `startViewTransition` yourself.

+ ### Animation Triggers

+ | Trigger | When it fires |

+ | ---------- | ------------------------------------------------------------------------------------------------- |

+ | **enter** | `<ViewTransition>` first inserted during a Transition |

+ | **exit** | `<ViewTransition>` first removed during a Transition |

+ | **update** | DOM mutations inside a `<ViewTransition>`. With nested VTs, mutation applies to the innermost one |

+ | **share** | Named VT unmounts and another with same `name` mounts in the same Transition |

+ Only `startTransition`, `useDeferredValue`, or `Suspense` activate VTs. Regular `setState` does not animate.

+ ### Critical Placement Rule

+ `<ViewTransition>` only activates enter/exit if it appears **before any DOM nodes**:

+ ```jsx

+ // Works

+ <ViewTransition enter="auto" exit="auto">

+ <div>Content</div>

+ </ViewTransition>

+ // Broken — div wraps the VT, suppressing enter/exit

+ <div>

+ <ViewTransition enter="auto" exit="auto">

+ <div>Content</div>

+ </ViewTransition>

+ </div>

+ ```

+

+ ---

+

+ ## Styling with View Transition Classes

+

+ ### Props

+

+ Values: `"auto"` (browser cross-fade), `"none"` (disabled), `"class-name"` (custom CSS), or `{ [type]: value }` for type-specific animations.

+

+ ```jsx

+ <ViewTransition

+ default="none"

+ enter="slide-in"

+ exit="slide-out"

+ share="morph"

+ />

+ ```

+

+ If `default` is `"none"`, all triggers are off unless explicitly listed.

+

+ ### CSS Pseudo-Elements

+

+ - `::view-transition-old(.class)` — outgoing snapshot

+ - `::view-transition-new(.class)` — incoming snapshot

+ - `::view-transition-group(.class)` — container

+ - `::view-transition-image-pair(.class)` — old + new pair

+

+ See `references/css-recipes.md` for ready-to-use animation recipes.

+

+ ---

+

+ ## Transition Types

+

+ Tag transitions with `addTransitionType` so VTs can pick different animations based on context. Call it multiple times to stack types — different VTs in the tree react to different types:

+

+ ```jsx

+ startTransition(() => {

+ addTransitionType("nav-forward");

+ addTransitionType("select-item");

+ router.push("/detail/1");

+ });

+ ```

+

+ Pass an object to map types to CSS classes. Works on `enter`, `exit`, **and** `share`:

+

+ ```jsx

+ <ViewTransition

+ enter={{

+ "nav-forward": "slide-from-right",

+ "nav-back": "slide-from-left",

+ default: "none",

+ }}

+ exit={{

+ "nav-forward": "slide-to-left",

+ "nav-back": "slide-to-right",

+ default: "none",

+ }}

+ share={{

+ "nav-forward": "morph-forward",

+ "nav-back": "morph-back",

+ default: "morph",

+ }}

+ default="none"

+ >

+ <Page />

+ </ViewTransition>

+ ```

+

+ `enter` and `exit` don't have to be symmetric. For example, fade in but slide out directionally:

+

+ ```jsx

+ <ViewTransition

+ enter={{ 'nav-forward': 'fade-in', 'nav-back': 'fade-in', default: 'none' }}

+ exit={{ 'nav-forward': 'nav-forward', 'nav-back': 'nav-back', default: 'none' }}

+ default="none"

+ >

+ ```

+

+ **TypeScript:** `ViewTransitionClassPerType` requires a `default` key in the object.

+

+ For apps with multiple pages, extract the type-keyed VT into a reusable wrapper:

+

+ ```jsx

+ export function DirectionalTransition({ children }: { children: React.ReactNode }) {

+ return (

+ <ViewTransition

+ enter={{ 'nav-forward': 'nav-forward', 'nav-back': 'nav-back', default: 'none' }}

+ exit={{ 'nav-forward': 'nav-forward', 'nav-back': 'nav-back', default: 'none' }}

+ default="none"

+ >

+ {children}

+ </ViewTransition>

+ );

+ }

+ ```

+

+ ### `router.back()` and Browser Back Button

+

+ `router.back()` and the browser's back/forward buttons do **not** trigger view transitions (`popstate` is synchronous, incompatible with `startViewTransition`). Use `router.push()` with an explicit URL instead.

+

+ ### Types and Suspense

+

+ Types are available during navigation but **not** during subsequent Suspense reveals (separate transitions, no type). Use type maps for page-level enter/exit; use simple string props for Suspense reveals.

+

+ ---

+

+ ## Shared Element Transitions

+

+ Same `name` on two VTs — one unmounting, one mounting — creates a shared element morph:

+

+ ```jsx

+ <ViewTransition name="hero-image">

+ <img src="/thumb.jpg" onClick={() => startTransition(() => onSelect())} />

+ </ViewTransition>

+

+ // On the other view — same name

+ <ViewTransition name="hero-image">

+ <img src="/full.jpg" />

+ </ViewTransition>

+ ```

+

+ - Only one VT with a given `name` can be mounted at a time — use unique names (`photo-${id}`). Watch for reusable components: if a component with a named VT is rendered in both a modal/popover _and_ a page, both mount simultaneously and break the morph. Either make the name conditional (via a prop) or move the named VT out of the shared component into the specific consumer.

+ - `share` takes precedence over `enter`/`exit`. Think through each navigation path: when no matching pair forms (e.g., the target page doesn't have the same name), `enter`/`exit` fires instead. Consider whether the element needs a fallback animation for those paths.

+ - Never use a fade-out exit on pages with shared morphs — use a directional slide instead.

+

+ ---

+

+ ## Common Patterns

+

+ ### Enter/Exit

+

+ ```jsx

+ {

+ show && (

+ <ViewTransition enter="fade-in" exit="fade-out">

+ <Panel />

+ </ViewTransition>

+ );

+ }

+ ```

+

+ ### List Reorder

+

+ ```jsx

+ {

+ items.map((item) => (

+ <ViewTransition key={item.id}>

+ <ItemCard item={item} />

+ </ViewTransition>

+ ));

+ }

+ ```

+

+ Trigger inside `startTransition`. Avoid wrapper `<div>`s between list and VT.

+

+ ### Composing Shared Elements with List Identity

+

+ Shared elements and list identity are independent concerns — don't confuse one for the other. When a list item contains a shared element (e.g., an image that morphs into a detail view), use two nested `<ViewTransition>` boundaries:

+

+ ```jsx

+ {

+ items.map((item) => (

+ <ViewTransition key={item.id}>

+ {" "}

+ {/* list identity */}

+ <Link href={`/items/${item.id}`}>

+ <ViewTransition name={`item-image-${item.id}`} share="morph">

+ {" "}

+ {/* shared element */}

+ <Image src={item.image} />

+ </ViewTransition>

+ <p>{item.name}</p>

+ </Link>

+ </ViewTransition>

+ ));

+ }

+ ```

+

+ The outer VT handles list reorder/enter animations. The inner VT handles the cross-route shared element morph. Missing either layer means that animation silently doesn't happen.

+

+ ### Force Re-Enter with `key`

+

+ ```jsx

+ <ViewTransition key={searchParams.toString()} enter="slide-up" default="none">

+ <ResultsGrid />

+ </ViewTransition>

+ ```

+

+ **Caution:** If wrapping `<Suspense>`, changing `key` remounts the boundary and refetches.

+

+ ### Suspense Fallback to Content

+

+ Simple cross-fade:

+

+ ```jsx

+ <ViewTransition>

+ <Suspense fallback={<Skeleton />}>

+ <Content />

+ </Suspense>

+ </ViewTransition>

+ ```

+

+ Directional reveal:

+

+ ```jsx

+ <Suspense

+ fallback={

+ <ViewTransition exit="slide-down">

+ <Skeleton />

+ </ViewTransition>

+ }

+ >

+ <ViewTransition enter="slide-up" default="none">

+ <Content />

+ </ViewTransition>

+ </Suspense>

+ ```

+

+ For more patterns, see `references/patterns.md`.

+

+ ---

+

+ ## How Multiple VTs Interact

+

+ Every VT matching the trigger fires simultaneously in a single `document.startViewTransition`. VTs in **different** transitions (navigation vs later Suspense resolve) don't compete.

+

+ ### Use `default="none"` Liberally

+

+ Without it, every VT fires the browser cross-fade on **every** transition — Suspense resolves, `useDeferredValue` updates, background revalidations. Always use `default="none"` and explicitly enable only desired triggers.

+

+ ### Two Patterns Coexist

+

+ **Pattern A — Directional slides:** Type-keyed VT on each page, fires during navigation.

+ **Pattern B — Suspense reveals:** Simple string props, fires when data loads (no type).

+

+ They coexist because they fire at different moments. `default="none"` on both prevents cross-interference. Always pair `enter` with `exit`. Place directional VTs in page components, not layouts.

+

+ ### Nested VT Limitation

+

+ When a parent VT exits, nested VTs inside it do **not** fire their own enter/exit — only the outermost VT animates. Per-item staggered animations during page navigation are not possible today. See [react#36135](https://github.com/facebook/react/pull/36135) for an experimental opt-in fix.

+

+ ---

+

+ ## Next.js Integration

+

+ For Next.js setup (`experimental.viewTransition` flag, `transitionTypes` prop on `next/link`, App Router patterns, Server Components), see `references/nextjs.md`.

+

+ ---

+

+ ## Accessibility

+

+ Always add the reduced motion CSS from `references/css-recipes.md` to your global stylesheet.

+

+ ---

+

+ ## Reference Files

+

+ - **`references/implementation.md`** — Step-by-step implementation workflow.

+ - **`references/patterns.md`** — Patterns, animation timing, events API, troubleshooting.

+ - **`references/css-recipes.md`** — Ready-to-use CSS animation recipes.

+ - **`references/nextjs.md`** — Next.js App Router patterns and Server Component details.

+

+ ## Full Compiled Document

+

+ For the complete guide with all reference files expanded: `AGENTS.md`