mirror of
https://github.com/MBombeck/HealthLog.git
synced 2026-11-08 04:32:42 +00:00
59 lines
2.2 KiB
TypeScript
59 lines
2.2 KiB
TypeScript
"use client";
|
|
|
|
/**
|
|
* Client-side companion to `src/lib/optimistic-lock.ts` (server).
|
|
*
|
|
* The optimistic-concurrency recipe every guarded write follows, extracted
|
|
* from the shipped `/api/dashboard/widgets` client (issue #581):
|
|
*
|
|
* 1. Read the freshest token straight from the query cache AT MUTATE TIME
|
|
* (`readUpdatedAtToken`) — not a render snapshot — so it reflects
|
|
* whatever the last settled write or refetch advanced it to.
|
|
* 2. Echo it on the write body as `baseUpdatedAt` (`withBaseToken`); omit
|
|
* the field entirely when no token is known yet, which takes the
|
|
* server's backward-compatible unconditional write.
|
|
* 3. On a 409 (`isConflict`), invalidate the read so the token advances,
|
|
* then either keep the draft (explicit-Save surfaces) or roll back the
|
|
* optimistic delta (instant-write surfaces) and re-apply against fresh
|
|
* state.
|
|
*
|
|
* No `useMutation` wrapper: every writer has bespoke optimistic / draft
|
|
* logic and a wrapper would obscure it. These are the three shared
|
|
* primitives the two dispositions are built from.
|
|
*
|
|
* The token is opaque — callers only ever echo a server-returned value.
|
|
*/
|
|
import type { QueryClient, QueryKey } from "@tanstack/react-query";
|
|
|
|
import { ApiError } from "./api-fetch";
|
|
|
|
/**
|
|
* The current optimistic-concurrency token for a read, straight from the
|
|
* query cache. Generalises the shipped `readBaseToken`: every guarded GET /
|
|
* write response carries an optional `updatedAt`, cached with its payload.
|
|
*/
|
|
export function readUpdatedAtToken(
|
|
queryClient: QueryClient,
|
|
queryKey: QueryKey,
|
|
): string | undefined {
|
|
return queryClient.getQueryData<{ updatedAt?: string }>(queryKey)?.updatedAt;
|
|
}
|
|
|
|
/**
|
|
* Attach the base token to a write payload only when it is known. A tokenless
|
|
* client transparently takes the server's unconditional write.
|
|
*/
|
|
export function withBaseToken<T extends object>(
|
|
payload: T,
|
|
token: string | undefined,
|
|
): T & { baseUpdatedAt?: string } {
|
|
return token !== undefined
|
|
? { ...payload, baseUpdatedAt: token }
|
|
: { ...payload };
|
|
}
|
|
|
|
/** True when a thrown error is an optimistic-concurrency 409. */
|
|
export function isConflict(err: unknown): boolean {
|
|
return err instanceof ApiError && err.status === 409;
|
|
}
|