moment-timezone.js – Getting Error When Running in Jest Test

[friendken]

Hi moment-timezone team,
Firstly, I want to thank you very much for great package.

I got an error using moment-timezone.js. It runs perfectly on a web page, but when I try to implement the test for it, the test result always returns an error like below.

import moment from 'moment-timezone';

class TimezoneCityItem extends React.Component {

  componentDidMount(){
    this.setState({
      time: moment.tz(this.props.timezone)
    })
  }

  render(){
    return (
      <div>{this.state.time.format('HH:mm')}</div>
    )
  }
}

This is timezoneListDummyData:

const timezoneList = [
  { name: 'los-angeles', title: 'Los Angeles', timezone: 'America/Los_Angeles' },
  { name: 'washington', title: 'Washington', timezone: 'America/New_York' },
  { name: 'london', title: 'London', timezone: 'Europe/London' },
  { name: 'dubai', title: 'Dubai', timezone: 'Asia/Dubai' },
  { name: 'hongkong', title: 'Hongkong', timezone: 'Asia/Hong_Kong' },
];

export default timezoneList;

this is code I use on my test file

import React from 'react';
import { shallow } from 'enzyme';
import TimezoneCityItem from '../TimezoneCity.item';
import timezoneList from '/lib/timezoneListDummyData'; // It just an array list of timezone

describe('<TimezoneCityItem />', () => {
   test('Should render TimezoneCityItem correctly', () => {
       const wrapper = shallow(<TimezoneCityItem {...timezoneList[0]} />);
       expect(wrapper).toMatchSnapshot();
   });
});

This is the version of the packages:

"moment": "~2.18.1",
"moment-timezone": "~0.5.13",

This is the error message:

Test suite failed to run
TypeError: Cannot read property 'split' of undefined

  at node_modules/moment-timezone/moment-timezone.js:36:34
  at Object.<anonymous>.moment (node_modules/moment-timezone/moment-timezone.js:14:20)
  at Object.<anonymous> (node_modules/moment-timezone/moment-timezone.js:18:2)
  at Object.<anonymous> (node_modules/moment-timezone/index.js:1:120)
  at Object.<anonymous> (imports/ui/components/mainLayout/TimezoneCity.item.jsx:3:49)
  at Object.<anonymous> (imports/ui/components/mainLayout/TimezoneCity.jsx:3:47)
  at Object.<anonymous> (imports/ui/components/mainLayout/MainLayout.jsx:6:47)
  at Object.<anonymous> (imports/ui/components/mainLayout/__tests__/MainLayout.test.js:3:19)
      at Generator.next (<anonymous>)
      at new Promise (<anonymous>)
      at Generator.next (<anonymous>)
      at <anonymous>

Please help me on this situation
Thanks & best regards

[m-vdb]

that's crazy that this bug isn't fixed...

[ellenaua]

@m-vdb How can I reproduce it?
Check pls this my repository, https://github.com/ellenaua/webpack-1/blob/master/src/index.js - can you change it in a way so that I get this error?

[m-vdb]

sorry @ellenaua I forgot to update my comment here. After spending two hours on this, I finally pinpointed the issue, and it was totally my fault. I was mocking moment explicitly (because I wanted to mock the timezone to UTC). Maybe it can help others if I post it here. Here was my code before:

//  test-setup.js
jest.mock('moment', () => {
  // UTC everywhere
  const moment = require.requireActual('moment');
  return moment.utc;
});

And I finally replaced that code with:

// test-setup.js
moment.tz.setDefault('UTC');

I honestly think that the initial issue report was similar to the one I had since jest auto mocks everything (what a pain...). If you agree, you can close this ✅

[osmyn]

I did something similar with mocking moment with moment-timezone:

    let diffMins = updateThreshold + 1;
    jest.mock('moment', () => {
      const mMoment = {
        diff: jest.fn(() => diffMins),
      };
      const fn = jest.fn(() => mMoment);
      fn.version = '2.24';
      fn.tz = jest.fn();
      fn.fn = jest.fn();
      return fn;
    });

[dtahoa]

sorry @ellenaua I forgot to update my comment here. After spending two hours on this, I finally pinpointed the issue, and it was totally my fault. I was mocking moment explicitly (because I wanted to mock the timezone to UTC). Maybe it can help others if I post it here. Here was my code before:

//  test-setup.js
jest.mock('moment', () => {
  // UTC everywhere
  const moment = require.requireActual('moment');
  return moment.utc;
});

And I finally replaced that code with:

// test-setup.js
moment.tz.setDefault('UTC');

I honestly think that the initial issue report was similar to the one I had since jest auto mocks everything (what a pain...). If you agree, you can close this ✅

// test-setup.js
moment.tz.setDefault('UTC');

This works like a charm.

[testacode]

Doesn't work for me :( Tests passes but the log is angry.

_moment: 2.26.0
moment-timezone: 0.5.3 (with data included)_

edit: adding image + info

[dtahoa]

@testacode try to setup test like this:
// test-setup.js
moment.tz.setDefault('UTC');