# Supabase Studio

Next.js pages router + TanStack Start (mid-migration, see below), React 19. Dev server: `pnpm dev:studio` → http://localhost:8082.

## Skills — load before working

Load the skills matching the task; stack them when a task spans areas:

| Task                                                                      | Additional skills                                                                                 |
| ------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------- |
| Query/mutation hooks, query keys (`data/**`)                              | `studio-queries`                                                                                  |
| UI: pages, forms, tables, charts, sheets, empty states                    | `studio-ui-patterns`                                                                              |
| Form logic: react-hook-form fields, watch/formState, reset, number inputs | `react-hook-form`                                                                                 |
| Displaying API errors                                                     | `studio-error-handling`                                                                           |
| Tests (deciding, writing, reviewing)                                      | `studio-testing`, then `studio-mock-api-tests` (component/MSW) or `studio-e2e-tests` (Playwright) |
| PostHog event tracking                                                    | `telemetry-standards`                                                                             |
| SQL against user databases                                                | `safe-sql-execution`                                                                              |
| Logs Explorer SQL, `data/logs`                                            | `clickhouse-logs-queries`                                                                         |
| Component API design, boolean-prop refactors                              | `vercel-composition-patterns`                                                                     |
| Keyboard shortcuts, search/filter inputs                                  | `studio-shortcuts`                                                                                |
| User-facing copy                                                          | `copywriting`                                                                                     |

## TanStack Start migration

Studio is migrating from the Next.js pages router (`pages/**`) to TanStack Start (`routes/**`). Both runtimes ship side-by-side; the `STUDIO_FRAMEWORK` env var selects which one `pnpm dev`/`build` runs (default: `next`, resolved in `scripts/dispatch.js`). Full route map and strategy: `TANSTACK_MIGRATION.md`.

- **Never delete a page file.** Most `routes/**` files are thin wrappers re-exporting the default export of their `pages/**` counterpart, so the Next file is load-bearing for both runtimes until the final cleanup pass.
- Pure page-body edits propagate to the route automatically. Mirror a change by hand into the corresponding `routes/**` file only when it touches what the route duplicates: `getLayout`/layout wrapping, page titles or other `staticData` (incl. `skip*Layout` flags), `withAuth`, or redirect paths.
- A new page under `pages/**` needs a matching route under `routes/**` plus a checklist entry in `TANSTACK_MIGRATION.md`.
- New code uses native TanStack APIs — no `next/router` or `next/link`. The `compat/next/` shims exist only for legacy re-exported pages.
- `routeTree.gen.ts` is generated by the Vite plugin — never hand-edit.

## Orientation

- **Data layer** — all platform API calls go through `data/fetchers.ts` (`openapi-fetch`, typed by the generated `api-types` package) with `handleError`; never raw `fetch`. One folder per resource in `data/`, most with a `keys.ts` query-key factory.
- **State** — valtio for global state (`state/`), nuqs for URL state, react-hook-form + zod for forms.
- **Platform vs self-hosted** — `IS_PLATFORM` gates platform-only behavior; `withAuth` is a no-op when self-hosted.
- **Telemetry** — `useTrack()` from `lib/telemetry/track`; event types live in `packages/common/telemetry-constants.ts`.
- **Tests** — default to including relevant tests with any change: a couple of unit tests for extracted logic, component tests for UI behavior, E2E only when the scope demands it (`studio-testing` has the decision tree). Not every PR needs them, but "no tests" should be a considered choice, not the default. Tooling: vitest + MSW; component tests use `customRender` + `addAPIMock` from `tests/lib/`; unhandled network requests fail tests. Don't `vi.mock('@/data/...')`.
- **Shortcuts** — use the registry in `state/shortcuts/` and `components/ui/Shortcut*.tsx`; keep `G then …` chords for navigation; no one-off keyboard listeners (`studio-shortcuts` has the full pattern, including the search-input Escape handler).
- **Scoped PAT catalog** — `packages/shared-data/scoped-access-token-permissions.ts` feeds Studio and the generated Personal Access Tokens guide. After changing it, run `make -C apps/docs/spec generate.partials.access-control`; Docs Tests rejects stale tables.
- **Reuse first** — before writing a new hook or helper, search for an existing one (`hooks/`, `lib/`, `packages/common`, `packages/ui-patterns`). If you do need a new one, make it as reusable as possible: general naming, no page-specific coupling, placed where other callers can find it.
- Co-locate sub-components with their parent; avoid barrel re-export files.

## Code style

Older Studio code predates some of these conventions. For new or modified code, follow them rather than mirroring nearby legacy patterns:

- **Booleans** read as `is`/`has`/`can`/`should`. Derive them from existing state (`const isFormValid = name.length > 0 && email.includes('@')`) — mirroring a derivable value into `useState` synced by `useEffect` is a bug pattern. Give multi-condition logic a name (`const canShowAddButton = !isSchemaLocked && canUpdateColumns && …`) instead of inlining the chain in JSX.
- **Ternaries**: one is fine for a binary choice; never nest them. Anything bigger flattens — early returns in statement position, sibling `&&` blocks in JSX.
- **Fetch states** render with early returns at the top level, or a flat `&&` chain with mutually exclusive guards inline — never a nested ternary:

  ```tsx
  // Top level: early return per state
  if (isLoading) return <GenericSkeletonLoader />
  if (isError) return <AlertError error={error} subject="Failed to retrieve data" />
  if (isSuccess && data.length === 0) return <EmptyState />
  return <DataDisplay data={data} />

  // Inline: flat `&&` blocks, mutually exclusive guards
  <div>
    {isLoading && <ShimmeringLoader />}
    {isError && <AlertError error={error} />}
    {isSuccess && data.length === 0 && <EmptyState />}
    {isSuccess && data.length > 0 && <DataDisplay data={data} />}
  </div>
  ```

- **`useEffect` is for synchronizing with external systems** (subscriptions, DOM, timers) — not for deriving data (compute it in render), reacting to user actions (do it in the handler), or fetching (React Query). Older code uses effects for all of these; don't copy it.
- **State** stays as local as possible — lift it only when it's actually shared. Related form fields belong in a single react-hook-form + zod form, not parallel `useState` calls.
- **Component size**: split at ~200–300 lines — or sooner when a component grows multiple distinct UI sections, tangled conditional rendering, or clusters of unrelated `useState`. Extract repeated JSX into small components, non-trivial pure logic into `.utils.ts` functions (which get unit tests), and reusable stateful logic into custom hooks.
- **Memoization is not the default**: `useMemo`/`useCallback` only for measured expense or referential stability a memoized child depends on.
- **TypeScript**: avoid `as` casts — where external data enters, parse it with zod (`schema.parse`/`safeParse`) instead. Model multi-state values as discriminated unions (`{ status: 'success'; data: T } | { status: 'error'; error: Error }`) rather than independent boolean flags.
- **Naming**: prop callbacks are `onX`, internal handlers are `handleX`. Custom hooks return objects, not tuples.
- **Refactoring**: when you move or extract code into a new module, update every importer to point at the new location directly — do **not** leave a re-export shim in the old file "for backward compatibility." It's a one-line import change per consumer, and keeping shims around makes the codebase messy and the true source of a symbol ambiguous.

## Defaults that differ here

- **ESLint warnings are ratcheted in CI**: the per-rule occurrence count must not increase, so a new `any`, unresolved `exhaustive-deps` warning, or default export fails the build even though it's "only a warning". Check locally with `pnpm --filter studio run lint:ratchet`.
- **Dead files and deps are gated in CI** by knip (`pnpm knip --workspace apps/studio` locally). Framework-convention files nothing imports (routes, Vercel functions, TanStack Start files) belong in `knip.jsonc` under `workspaces["apps/studio"].entry`, not `ignore` — an ignored file's imports aren't traced, so anything only it uses gets reported as dead. There's no inline `knip-ignore` comment; the only per-file opt-out is config. In a PR stack, a file whose first consumer lands in a later PR fails the gate on the earlier one — either add it in the same PR as its first use, or add it to `workspaces["apps/studio"].ignore` with a `used from #NNN` comment and remove it in that PR.
- **Clipboard**: `copyToClipboard` from `'ui'`, and never `await` anything before calling it (Safari requires the write inside the user gesture; lint-enforced) — pass a Promise as the argument instead.
- **`useParams()` comes from `'common'`**, not `next/navigation` — it camelCases keys and returns `string | undefined`.
- **Permissions**: `useAsyncCheckPermissions` from `hooks/misc/useCheckPermissions` (returns `can: true` when self-hosted).
- **Gating**: `useIsFeatureEnabled` for product features, `useFlag` from `'common'` for feature flags — two different systems.
- **Dates**: `dayjs` (plugins pre-loaded at both entries, `pages/_app.tsx` and `routes/__root.tsx`), not `date-fns`. **Toasts**: `toast` from `'sonner'`.
- **Import split**: `'ui'` = primitives, `'ui-patterns'` = composed patterns (`ConfirmationModal`, …), `@ui/*` = alias into `packages/ui/src`. Icons come from `lucide-react`.
- **New tables** use `@tanstack/react-table`; `react-data-grid` is banned for new code.
- **Ad-hoc SQL** against the user's database goes through `executeSql` / `useExecuteSqlMutation` (`data/sql/execute-sql-mutation`).
- **Confirmations**: `ConfirmationModal` / `TextConfirmModal` from `ui-patterns`, never `window.confirm`. Disabled buttons needing an explanation use `ButtonTooltip`; inline warnings use `Admonition`.