Errors & requests

FrankfurterError

Non-2xx HTTP responses throw FrankfurterError.

Read-only fields:

Field	Meaning
status	HTTP status code
statusText	Status text from the response
url	Request URL
body	Parsed JSON body when possible, otherwise undefined
headers	Response Headers or undefined

import { FrankfurterClient, FrankfurterError } from "frankfurter-js";

const client = new FrankfurterClient();

try {
  await client.historical("invalid-date");
} catch (error) {
  if (error instanceof FrankfurterError) {
    console.error(error.status, error.statusText, error.url, error.body);
  } else {
    throw error;
  }
}

If fetch is missing from the environment and not passed in client options, the client throws a plain Error at construction time.

Timeout

const client = new FrankfurterClient({
  timeout: 5_000,
});

AbortSignal

Per-call cancellation or deadlines:

const controller = new AbortController();

const rates = await client.latest(
  { base: "EUR", quotes: ["USD"] },
  { signal: controller.signal },
);

Custom fetch

const client = new FrankfurterClient({
  fetch: window.fetch.bind(window),
});

Self-hosted base URL

const client = new FrankfurterClient({
  baseUrl: "https://rates.example.com",
});

The client ensures requests go to the /v2 API prefix unless your baseUrl already ends with /v2.