K6 date manipulation libraries ala dayjs

Grafana k6 OSS Support
1

I’ve always had a small pure js library for manipulating dates, but now I work on another project where this is taken to another level. So instead of investing in my own library, can I use libraries like npms dayjs - npm

2

Luckily dayjs has a minimized browser js, so it can be directly imported, I also included the utc extension. There is another extension I like to add dayjs-timezone-iana-plugin - npm, but it holds a iana database, I’ll probably just make the extraction what I need and pack it together:

$ cat test-dayjs.js
// https://cdn.jsdelivr.net/npm/dayjs@1.11.19/dayjs.min.js
import dayjs from ‘./tools/dayjs.min.js’;
// https://unpkg.com/dayjs-plugin-utc@0.1.2/dist/dayjs-plugin-utc.min.js
import utc from ‘./tools/dayjs-plugin-utc.min.js’;
// inject utc plugin to dayjs
dayjs.extend(utc);

export default function () {
const now = dayjs();
console.log(‘Current time:’, now.format(‘YYYY-MM-DD HH:mm:ss’));
const dt = dayjs().startOf(‘month’).add(1, ‘day’).set(‘year’, 2018).format(‘YYYY-MM-DD HH:mm:ss’);
console.log(‘specific time:’, dt);
const utct = dayjs(‘2022-11-30T21:00:00.00+01:00’).utc();
console.log(‘norwegian to utc time:’, utct);
const dayA = dayjs();
const dayB = dayA.clone().add(1, ‘day’);
const dayC = dayA.clone().subtract(1, ‘day’);
const dayD = dayA.clone().add(1, ‘month’);
console.log(dayC.isBefore(dayA)); // true
console.log(dayA.isSame(dayjs())); // false microsecdiff
console.log(dayB.isAfter(dayA)); // true
console.log(dayA.isSame(dayD)); // false
console.log(dayB.isAfter(dayD)); // false
console.log(dayC.isBefore(dayD)); // true
// generate one month of dates from today
let days =
for (let d=dayA.clone(); d<=dayD; d=d.add(1, ‘day’)) {
days.push(d.format(‘YYYY-MM-DD’));
}
console.log(days);
}

$ k6 -q run test-dayjs.js
INFO[0000] Current time: 2025-11-21 14:17:05 source=console
INFO[0000] specific time: 2018-11-02 00:00:00 source=console
INFO[0000] norwegian to utc time: “2022-11-30T20:00:00.000Z” source=console
INFO[0000] true source=console
INFO[0000] false source=console
INFO[0000] true source=console
INFO[0000] false source=console
INFO[0000] false source=console
INFO[0000] true source=console
INFO[0000] [“2025-11-21”,“2025-11-22”,“2025-11-23”,“2025-11-24”,“2025-11-25”,“2025-11-26”,“2025-11-27”,“2025-11-28”,“2025-11-29”,“2025-11-30”,“2025-12-01”,“2025-12-02”,“2025-12-03”,“2025-12-04”,“2025-12-05”,“2025-12-06”,“2025-12-07”,“2025-12-08”,“2025-12-09”,“2025-12-10”,“2025-12-11”,“2025-12-12”,“2025-12-13”,“2025-12-14”,“2025-12-15”,“2025-12-16”,“2025-12-17”,“2025-12-18”,“2025-12-19”,“2025-12-20”,“2025-12-21”] source=console

█ TOTAL RESULTS

EXECUTION
iteration_duration...: avg=14.55ms min=14.55ms med=14.55ms max=14.55ms p(90)=14.55ms p(95)=14.55ms
iterations...........: 1   68.24957/s

NETWORK
data_received........: 0 B 0 B/s
data_sent............: 0 B 0 B/s