# @lovable.dev/vite-tanstack-config

Vite config wrapper for Lovable TanStack Start projects.

## What It Does

- Gives TanStack Start projects a single `defineConfig` helper for local preview and production builds.
- Keeps Lovable sandbox previews predictable by setting the server shape, watched paths, HMR coordination, and asset routing expected by the platform.
- Adds diagnostics that help the preview tell build, Vite, SSR, and app errors apart.
- Produces deployable build output for Lovable while still letting self-hosted projects choose their own target.

## Customization

Apps can pass through Vite options and adjust the React, TanStack Start, Nitro, HMR gate, and error-logging behavior when they need to.

## Build exit watchdog

Inside a Lovable build with prerender enabled, the build process is forced to exit if it is still alive 60 seconds after the last build hook has returned, and a `[lovable-build-exit-report]` block naming the open handle types is written to stderr. Adjust it with `defineConfig({ buildExitWatchdog: { graceMs, enabled } })`; the grace is clamped to 5 s–10 min. The `LOVABLE_PRERENDER_EXIT_GRACE_MS` and `LOVABLE_PRERENDER_EXIT_WATCHDOG=off` environment variables override the config.

## Route manifest

Inside a Lovable build, the route surface of the app is written to `dist/.lovable/routes.json` after the build: `{ version, generator, basepath?, serverEntry, requestMiddleware?, routes }`, where `routes` is the generated route tree's `fullPaths` union in TanStack path syntax (`/posts/$postId`, `/files/$`, `/docs/{-$version}`). Lovable's serving layer uses it to answer requests no route can match without starting the app. The file is enumerated with `@tanstack/router-generator` through an in-memory overlay, so the build never rewrites `routeTree.gen.ts`, and it is skipped — with a warning naming the reason — whenever the app can answer paths outside its route tree: `tanstackStart.spa`, `router.virtualRouteConfig`, `nitro.routeRules`/`handlers`, a project `nitro.config.*` / `.config/nitro.*` / `.nitrorc` file (Nitro loads it on its own, so the wrapper cannot see what it adds), a `rewrite` in the router file, a `basepath` there that `tanstackStart.router.basepath` does not declare (a computed or shorthand one included), or a router file (`router.entry`, resolved the way TanStack Start resolves it) that cannot be read to check either.