chronokinesis

Mock time and date for traveling and freezing. Inspired and borrowed from timekeeper.

• Introduction
• API Reference
  • freeze([...args])
  • travel([...args])
  • defrost()
  • reset()
  • isKeepingTime()
  • timezone(timeZone[, ...args])
  • new TimeZoneTraveller(timeZone)
    • timezone.freeze([...args])
    • timezone.travel([...args])
    • timezone.reset()
    • timezone.defrost()
• Distributions
  • Nodejs require
  • Browser (UMD)
• Acknowledgements

Introduction

Mock Date and Date.now in order to help you test time-dependent code. Provides travel, freeze, and timezone functionality for your Node.js tests.

1import * as ck from 'chronokinesis';
2
3ck.freeze();
4
5setTimeout(() => {
6  // Frozen
7  console.log(new Date());
8
9  ck.reset();
10}, 2000);

or use with moment:

1import moment from 'moment';
2import * as ck from 'chronokinesis';
3
4ck.travel(moment().add(1, 'year'));
5
6setTimeout(() => {
7  // Date traveled one year and some
8  console.log(new Date());
9
10  ck.reset();
11}, 2000);

API Reference

freeze([...args])

Freeze point in time. Calls can be made with the same arguments as the Date constructor.

• ...args: Optional date constructor arguments, if empty stops time at now

1import * as ck from 'chronokinesis';
2
3ck.freeze('1942-01-08');
4
5setTimeout(() => {
6  // Frozen
7  console.log(new Date());
8
9  ck.reset();
10}, 2000);

travel([...args])

Time travel to another era. Calls can be made with the same arguments as the Date constructor

• ...args: Optional date constructor arguments, pretty useless if empty but won´t crash

1import * as ck from 'chronokinesis';
2let date = new Date(2018, 0, 31);
3
4ck.travel(date);
5
6setTimeout(function() {
7  console.log(new Date());
8  ck.reset();
9}, 1500);

When used in combination with freeze the time is still frozen but at the travelled time().

1import * as ck from 'chronokinesis';
2import moment from 'moment';
3
4let date = new Date(2018, 0, 31);
5
6ck.freeze(date);
7
8ck.travel(moment().add(1, 'year'));
9
10setTimeout(function() {
11  console.log(`Still frozen but one year ahead ${new Date()}`);
12
13  ck.reset();
14}, 1500);

defrost()

Defrost a frozen point in time. Used in combination with travelling will start ticking the clock.

1import * as ck from 'chronokinesis';
2
3ck.freeze(1980, 0, 1);
4
5// Travel one year
6ck.travel(1981, 1, 1);
7
8// Start ticking
9ck.defrost();
10
11setTimeout(() => {
12  // Tick tack
13  console.log(new Date());
14
15  ck.reset();
16}, 2000);

reset()

Resets Date to current glory.

1import * as ck from 'chronokinesis';
2
3ck.freeze(2060, 0, 1);
4console.log(`end of time is reached at ${new Date()} according to Newton`)
5
6ck.reset();
7
8// Today
9console.log(new Date())

isKeepingTime()

Utility function to see if we still travel or freeze time.

1import * as ck from 'chronokinesis';
2
3console.log(ck.isKeepingTime() ? 'Is' : 'Not', 'keeping time');
4ck.travel(1893448800000);
5console.log(ck.isKeepingTime() ? 'Is' : 'Not', 'keeping time');

timezone(timeZone[, ...args])

Travel to time zone.

• timeZone: IANA time zone string
• ...args: Optional travel to date arguments

Returns TimeZoneTraveller api

1import * as ck from 'chronokinesis';
2
3const tz = ck.timezone('Asia/Shanghai');
4
5// Now in Shanghai
6console.log(new Date())
7
8tz.freeze();

new TimeZoneTraveller(timeZone)

Time zone traveller api.

1import {TimeZoneTraveller} from 'chronokinesis';
2
3const timezone = new TimeZoneTraveller('Asia/Shanghai');
4
5timezone.freeze();

timezone.freeze([...args])

Freeze at the specific timezone.

timezone.travel([...args])

Start traveling in the specific timezone.

timezone.reset()

Same as #reset

timezone.defrost()

Same as #defrost

Distributions

The module is prepared for browser and nodejs.

Nodejs require

1const ck = require('chronokinesis');

Browser (UMD)

Use dist/chronokinesis.cjs. Sets global property chronokinesis.

Acknowledgements

chronokinesis initial code is inspired and borrowed from timekeeper