Front end: screens call the server through one typed client

Omnibeds screens never build a URL or call fetch for an action. They call api() from lib/client/api.ts with a command’s name, and the compiler checks the input and the answer against that command.

Call a command

import { api } from "@/lib/client/api";

const res = await api("cancel", { reference: booking.reference, mode }, t("doingCancel"));
if (!res.ok) return showProblem(res.problem, t("couldntCancel"));
setSelected(res.data.booking);

Argument	What it is
`name`	The command’s export name, such as `cancel` or `openQuote`.
`input`	The command’s schema input. Fields with defaults may be left out. Route params such as `reference` are part of it.
`doing`	The action in words, used in the error message (“Cancelling the booking”).

api() never throws. It returns { ok: true, data } or { ok: false, problem }, where problem is what the server explained: a code, a message, and any extra fields in details (for example the refreshed price check when an offer changed).

How it finds the URL

ROUTES maps every command to its method and path, for example cancel: POST /api/cancel and rebookBook: POST /api/bookings/:reference/rebook. api() fills :params from the input, then sends the rest as a query string for GET and DELETE, or as a JSON body otherwise. For a link the browser opens itself, such as a PDF download, apiUrl(name, input) returns the URL of a GET command.

Only types cross into the browser: lib/client/api.ts imports the command modules with import type, so no server code is bundled into a screen.

Keep logic out of screens

A page places its parts and holds no business rules. When a page grows, its state and its calls move into a hook, and its sections into components:

Page	Hook (state and calls)	Parts
Book an offer	`components/book/use-booking-flow.ts`	`components/book/steps.tsx`, `parts.tsx`
A quote	`components/quotes/detail/use-quote-detail.ts`	header actions, banners, options, client panel

Rules that aren’t about display live in lib/, where they can be tested without a browser: search filtering and merging in lib/search/, and the traveller helpers (a party from saved travellers, age checks on arrival) in lib/travellers/.

Calls that stay outside api()

A few calls aren’t commands and keep their own fetch: the search stream and its sentence parser, presenter unlock, the user switcher (session), the quota counter, the access gate, the guided tour and the client’s accept link on a shared quote.

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Operations

Front end: screens call the server through one typed client

Call a command

How it finds the URL

Keep logic out of screens

Calls that stay outside api()