Need private packages and team management tools?Check out npm Teams »

jest-date-mock

1.0.8 • Public • Published

jest-date-mock

Mock Date when run unit test cases with jest. Make tests of Date easier.

Build Status Coverage Status npm npm

Install

This should only be installed as a development dependency (devDependencies) as it is only designed for testing.

npm i --save-dev jest-date-mock

Setup

In your package.json under the jest, create a setupFiles array and add jest-date-mock to the array.

{
  "jest": {
    "setupFiles": ["jest-date-mock"]
  }
}

If you already have a setupFiles attribute you can also append jest-date-mock to the array.

{
  "jest": {
    "setupFiles": ["./__setups__/other.js", "jest-date-mock"]
  }
}

More about in configuration section.

Setup file

Alternatively you can create a new setup file which then requires this module or add the require statement to an existing setup file.

__setups__/date.js

import 'jest-date-mock';
// or
require('jest-date-mock');

Add that file to your setupFiles array:

"jest": {
  "setupFiles": [
    "./__setups__/date.js"
  ]
}

Usage

Use the only 3 api for test cases.

  • advanceBy(ms): advance date timestamp by ms.
  • advanceTo([timestamp]): reset date to timestamp, default to 0.
  • clear(): shut down the mock system.
import { advanceBy, advanceTo, clear } from 'jest-date-mock';
 
test('usage', () => {
  advanceTo(new Date(2018, 5, 27, 0, 0, 0)); // reset to date time.
 
  const now = Date.now();
 
  advanceBy(3000); // advance time 3 seconds
  expect(+new Date() - now).toBe(3000);
 
  advanceBy(-1000); // advance time -1 second
  expect(+new Date() - now).toBe(2000);
 
  clear();
  Date.now(); // will got current timestamp
});

More sample code here.

Also, add an API Date.current() to get the actual current timestamp.

import { advanceBy, advanceTo, clear } from 'jest-date-mock';
 
advanceTo(0); // reset to timestamp = 0
 
Date.now(); // will got 0
 
Date.current(); // will got the actual timestamp.

License

MIT@hustcc.

Install

npm i jest-date-mock

DownloadsWeekly Downloads

110,626

Version

1.0.8

License

MIT

Unpacked Size

10.3 kB

Total Files

8

Last publish

Collaborators

  • avatar