Errors & guards

HttpError

Thrown by the client when a response has a non-2xx status (unless throwOnError: false).

class HttpError<T = unknown> extends Error {
  readonly name: 'HttpError';
  readonly status: number;
  readonly statusText: string;
  readonly url: string;
  readonly response: Response; // a clone, taken before reading — still readable
  readonly data: T; //           best-effort parse of the error body
}

• response is a clone taken before the body was read, so await err.response.text() / .json() still works.
• data is a best-effort parse (JSON or text) of the error body. It's unknown by default since error shapes aren't known at compile time, but the class is generic: name the payload via the guard to type it without a cast (see below).

try {
  await corgi.get('https://api.example.com/nope');
} catch (err) {
  if (isHttpError(err)) {
    console.error(err.status, err.data);
  }
}

isHttpError

function isHttpError<T = unknown>(error: unknown): error is HttpError<T>;

Type guard for HttpError, checked by name rather than instanceof (why).

Name the error payload to type err.data with no cast. The type argument is an unchecked assertion (the guard only verifies it's an HttpError), so pass the shape you know the endpoint returns:

try {
  await corgi.get('https://api.example.com/users/1');
} catch (err) {
  if (isHttpError<ApiError>(err)) {
    err.data.code;
  }
}

isTimeoutError

function isTimeoutError(error: unknown): boolean;

True when a deadline fired, from either timeout implementation or an AbortSignal.timeout. Both abort with a DOMException named "TimeoutError". Name-based, not instanceof.

isAbortError

function isAbortError(error: unknown): boolean;

True when the caller cancelled, or an abortPrevious call superseded this one. Caller aborts use the name "AbortError".

if (isTimeoutError(err)) {
  // deadline fired
} else if (isAbortError(err)) {
  // cancelled by the caller / superseded
}

ValidationError

Thrown by schema() on a failed validation, distinct from HttpError and network errors. See schema. Detect with isValidationError (also name-based).