ebx-timezone-mock

A JavaScript library which mocks the Date object and lets you specify a local date/time/timezone in order to enable consistent testing of date/time-related code independently of your local system time settings.

It works by monkey patching the Date object and returning results which are adjusted to reflect the effects of both the specified current date/time/timezone (if any) and the current date/time/timezone. In particular, it avoids problems caused by certain JavaScript date/time methods e.g. getHours returning results in the user's local system time, so you can write date/time-related unit tests which will work whenever and wherever they are run, without changing timezones causing results to change.

Installation

NPM

$ npm install ebx-timezone-mock

Usage

Configuration

import TimezoneMock from 'TimezoneMock';
 
TimezoneMock.set('2018-04-25T12:34:56.000Z');
 
console.log(new Date()); // Wed Apr 25 2018 12:34:56 GMT+0000 (GMT Standard Time)
 
TimezoneMock.reset();
 
console.log(new Date()); // Current system date/time/timezone

Credits

The majority of the code for this project was taken from the timezone-mock project by Jimb Esser, with some additional code from the MockDate project by Bob Lauer. My contribution has been limited to gluing these two projects together, and introduction moment-timezone to solve the problem of working out the timezone offset for any given date, time and place.