Jest snapshot test failed with TypeError: Cannot read property 'extend' of undefined

Below is the sample code.

Filename: TestComponent.svelte
<script>
  import * as dayjs from 'dayjs'
  import relativeTime from 'dayjs/plugin/relativeTime'
  dayjs.extend(relativeTime)

  dayjs('1999-01-01').fromNow()
</script>
<div>
Hello World !!!
</div>

Filename: TestComponent.test.js

import { render } from '@testing-library/svelte'
import TestComponent from './TestComponent.svelte'

describe('Render component', () => {
  it('should render component correctly', () => {
    const { component } = render(TestComponent)
    expect(component).toMatchSnapshot()
  })
})

Information dayjs : 1.10.4

** Error **

[jeserkin]

Yes. Just had wrong import. For some reason it worked on application level both ways, but on test level it didn’t. Once the import was changed and was same on both sides it was working as intended. At the moment, I have following imports:

import { Dayjs } from 'dayjs';
import * as dayjs from 'dayjs';
import * as en from 'dayjs/locale/en';
import * as relativeTime from 'dayjs/plugin/relativeTime';

Also I am calling now dayjs.extend(...); inside constructor. This is my case, other people requirements can be different.

[harvanchik]

@rogerprz What version of Angular are you using? What version of dayjs?

Im using React with typescript. The latest "dayjs": "^1.10.7", The file is a javascript file.

Oh, hmm. Well, I’ve done basically the same thing as you, but in Angular, and get no error.