This is documentation for the next version of K6. For the latest stable release, go to the latest version.

Documentation

Grafana k6

JavaScript API

jslib

utils

Open source

utils

Note
The source code for this library can be found in the grafana/k6-jslib-utils GitHub repository.

The utils module contains number of small utility functions useful in every day load testing.

Function	Description
check(val, sets, [tags])	Drop-in replacement for `check` with support for async values.
randomIntBetween(min, max)	Random integer in a given range
randomItem(array)	Random item from a given array
randomString(length, [charset])	Random string of a given length, optionally selected from a custom character set
uuidv4()	Random UUID v4 in a string representation
findBetween(content, left, right, [repeat])	Extract a string between two surrounding strings
normalDistributionStages(maxVUs, durationSeconds, [numberOfStages])	Creates stages which will produce a normal distribution (bell-curve) of VUs for a test
getCurrentStageIndex	Get the index of the running stage as defined in the `stages` array options. It can be used only with the executors that support the `stages` option as ramping-vus or ramping-arrival-rate.
tagWithCurrentStageIndex	Tag all the generated metrics in the iteration with the index of the current running stage.
tagWithCurrentStageProfile	Tag all the generated metrics in the iteration with the computed profile for the current running stage.

Simple example

import { sleep } from 'k6';
import http from 'k6/http';

import {
  randomIntBetween,
  randomString,
  randomItem,
  uuidv4,
  findBetween,
} from 'https://jslib.k6.io/k6-utils/1.4.0/index.js';

export default function () {
  const res = http.post(`https://test-api.k6.io/user/register/`, {
    first_name: randomItem(['Joe', 'Jane']), // random name
    last_name: `Jon${randomString(1, 'aeiou')}s`, //random character from given list
    username: `user_${randomString(10)}@example.com`, // random email address,
    password: uuidv4(), // random password in form of uuid
  });

  // find a string between two strings to grab the username:
  const username = findBetween(res.body, '"username":"', '"');
  console.log('username from response: ' + username);

  sleep(randomIntBetween(1, 5)); // sleep between 1 and 5 seconds.
}