client/api.js -> api.ts. Types the fetch infrastructure: generic _fetch<T>
and get/post/put/patch/del<T> helpers, an ApiError interface (status/code/
details/data), a QueryParams type for the query-string builder, and File-typed
upload helpers. Endpoint response shapes are typed incrementally — most methods
default to Promise<unknown>; the ones consumed by typed .ts files get real
shapes (quickPay -> PaymentRecord, togglePaid -> TogglePaidResult, settings ->
settings map).
Typing togglePaid's result surfaced a latent narrowing bug in usePaymentActions:
the un-pay Undo closure read result.paymentId (number|undefined) inside a
deferred async callback where TS re-widens the if-narrowed value — fixed by
capturing the id in a const before the closure.
The 16 files importing '@/api.js' with an explicit extension were normalized to
'@/api' so Vite/TS resolve the .ts.
Verified: typecheck 0, lint 0 errors (47 warns), build green, 48 client tests,
and 17/17 e2e probe (every page renders, all API paths respond) — the central
fetch-module rename is runtime-safe.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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