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attempt ​

Execute an async function with retry + timeout handling and receive a discriminated result.

Signature ​

typescript
type AttemptOptions = {
  onError?: (err: unknown) => void;
  timeout?: number;
  times?: number;
};

type AttemptResult<R> = { ok: true; value: R } | { error: unknown; ok: false };

function attempt<T extends Fn, R = Awaited<ReturnType<T>>>(fn: T, options?: AttemptOptions): Promise<AttemptResult<R>>;

Parameters ​

  • fn - Function to execute.
  • options.times - Total attempts including the first (default: 3).
  • options.timeout - Per-attempt timeout in ms (default: 7000).
  • options.onError - Called once when all attempts fail.

Returns ​

A promise that resolves to:

  • { ok: true, value } on success
  • { ok: false, error } on failure

Examples ​

Basic usage ​

typescript
import { attempt } from '@vielzeug/toolkit';

const result = await attempt(async () => {
  if (Math.random() < 0.7) throw new Error('Random failure');
  return 'Success!';
});

if (result.ok) {
  console.log(result.value);
} else {
  console.error(result.error);
}

Retry + timeout ​

typescript
import { attempt } from '@vielzeug/toolkit';

const user = await attempt(() => fetch('/api/user').then((r) => r.json()), {
  times: 5,
  timeout: 10_000,
  onError: (err) => console.error('user fetch failed', err),
});

if (user.ok) {
  console.log(user.value);
}
  • retry - Retry async operations with backoff
  • race - Enforce minimum loading durations