Function selectFastestSuccessfulEndpoint

src/endpoint.ts:55–109

(
  endpoints: string[],
  tryEndpoint: (endpoint: string) => Promise<T>,
  now: () => number = Date.now,
)

};

export async function selectFastestSuccessfulEndpoint<T>(
  endpoints: string[],
  tryEndpoint: (endpoint: string) => Promise<T>,
  now: () => number = Date.now,
): Promise<{
  successes: EndpointAttemptSuccess<T>[];
  failures: EndpointAttemptFailure[];
}> {
  const attempts = await Promise.all(
    endpoints.map(async endpoint => {
      const start = now();
      try {
        const value = await tryEndpoint(endpoint);
        return {
          ok: true as const,
          endpoint,
          value,
          duration: now() - start,
        };
      } catch (error) {
        return {
          ok: false as const,
          endpoint,
          error: normalizeError(error),
        };
      }
    }),
  );

  const successes: EndpointAttemptSuccess<T>[] = [];
  const failures: EndpointAttemptFailure[] = [];

  for (const attempt of attempts) {
    if (attempt.ok) {
      successes.push({
        endpoint: attempt.endpoint,
        value: attempt.value,
        duration: attempt.duration,
      });
      continue;
    }

    failures.push({
      endpoint: attempt.endpoint,
      error: attempt.error,
    });
  }

  successes.sort((left, right) => left.duration - right.duration);

  return {
    successes,
    failures,
  };
}

export async function executeEndpointFallback<T>({
  configuredEndpoints,