With Native Fetch

The recommended approach is to pass a fetcher to your instance and use the method helpers (.get(), .post(), etc.):

Instance with fetcher

import { createExpectStatus } from "expect-status";

const api = createExpectStatus<{
  401: { message: string };
  403: { message: string };
  422: { fieldErrors: Record<string, string> };
}>({
  fetcher: (url, init) =>
    fetch(`https://api.example.com${url}`, {
      ...init,
      headers: { ...init?.headers, Authorization: `Bearer ${getToken()}` },
    }),
  defaults: {
    401: ({ message }) => router.push("/login"),
    403: "You do not have permission.",
    "5xx": "Service unavailable.",
  },
  onError: (err) => Sentry.captureException(err),
});

GET

const user = await api.get<User>("/users/me", 200);

POST

const org = await api.post<Organisation, CreateOrgInput>(
  "/organisations",
  data,
  201,
  {
    409: ({ organisationId }) => router.push(`/org/${organisationId}`),
    422: ({ fieldErrors }) => setFieldErrors(fieldErrors),
  },
);

PUT / PATCH / DELETE

const updated = await api.put<Organisation, UpdateOrgInput>(
  "/organisations/123",
  changes,
  200,
);

await api.patch<void, { name: string }>(
  "/organisations/123",
  { name: "New" },
  204,
);

await api.delete("/organisations/123", 204);

Per-call overrides

Pass headers, signal, or any RequestInit key alongside dispatch:

const flags = await api.get<FeatureFlags>("/feature-flags", 200, {
  headers: { "X-Region": "eu-west-1" },
  signal: abortController.signal,
  recover: () => DEFAULT_FLAGS,
});

SafeResult

const result = await api.get<User>("/users/me", 200, { throws: false });

if (result.ok) {
  renderUser(result.data);
} else {
  showError(result.error.message);
}

Without a fetcher (manual fetch)

You can also pass fetch() calls directly to expectStatus:

import { createExpectStatus, adapters } from "expect-status";

const expectStatus = createExpectStatus({
  adapter: adapters.fetch,
  defaults: { 401: "Please sign in.", "5xx": "Service unavailable." },
});

const user = await expectStatus(200, fetch("/api/users/1"));

See also

• createExpectStatus API — full options
• With Axios — Axios adapter details
• Custom Envelope — adapter for non-standard shapes