check( val, sets, [tags] )

The check function is a drop-in replacement for the built-in check, with added support for async values. Any Promises will be awaited, and the result is reported once the operation has been completed.

Parameter	Type	Description
val	any	Value to test.
sets	Record<string, any>	Tests (checks) to run on the value. Functions will be called. `Promise`s will be awaited.
tags (optional)	Record<string, string>	Extra tags to attach to metrics emitted.

Returns

Type	Description
Promise	boolean	`true` if all checks have succeeded, `false` otherwise. If any of the checked values was a `Promise`, the result is wrapped in a `Promise`.

Examples

Using check() with async values.

import http from 'k6/http';
import { fail } from 'k6';
import { check } from 'https://jslib.k6.io/k6-utils/1.5.0/index.js';

function waitFor(delay) {
  return new Promise((resolve) => {
    setTimeout(() => {
      resolve(true);
    }, delay);
  });
}

export default async function () {
  const res = http.get('https://httpbin.test.k6.io');

  const success = await check(res, {
    'passing promise as a value': waitFor(1000),
    'async function': async (res) => {
      await waitFor(500);

      return res.status === 200;
    },
  });

  if (!success) {
    fail('check did not succeed');
  }
}

For general usage of checks, refer to check(val, set, [tags]).