Toast

A complete toast / notification system in one file: call `toast()` — or `toast.success` / `.error` / `.info` / `.warning` / `.loading` / `.promise` — from anywhere in your app, and render a single `<Toaster />` at the root. No provider, no context, nothing to wire up. Use it for save and delete confirmations, form submission results, copy-to-clipboard feedback, async job status, optimistic updates that may fail, undo prompts, connection lost / restored notices, rate-limit and validation errors — any "it worked" or "it failed" message that should not interrupt what the user is doing. Common asks it answers: "toast notification react", "toast component shadcn", "snackbar component", "notification popup", "flash message", "alert toast", "undo toast with action button", "promise toast for async requests", "loading toast that turns into success", "toast without a provider", "toast from outside a component", "sonner alternative", "react-hot-toast alternative", "react-toastify alternative", "notification system react", "show a message after form submit". `toast.promise(request, { loading, success, error })` moves one toast through all three states in place, so an async call needs a single line instead of a chain of manual dismissals — `success` and `error` also accept a function, so the final message can quote the resolved value or the thrown error. Every toast takes a `description`, an `action` button (the undo affordance), a `duration` where `Infinity` pins it until dismissed, and an `id` you can reuse to update a toast already on screen. `<Toaster />` takes any of six positions. The queue lives outside React through useSyncExternalStore, so a toast can be fired from an event handler, a fetch or axios interceptor, a route guard, or a plain module — the places a hook-based API cannot reach, and the usual reason a toast library ends up wrapped in a context that has to be threaded everywhere. The details a rushed implementation drops: auto-dismiss pauses while the pointer is over the stack or focus is inside it, so a toast cannot vanish mid-sentence or while a keyboard user is reaching for its action button, and it stays paused across a promise's loading → success swap. Errors announce assertive and everything else polite, so a failure is not queued behind three success messages. Swipe-to-dismiss on touch, and enter / exit animations that respect prefers-reduced-motion. Official shadcn/ui no longer ships a toast of its own — it points at sonner, an npm dependency you do not control. This is one file you own and can edit, styled with your own theme tokens, whose only package import is lucide-react (already present in a shadcn project).