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Discussion on: Testing with Jest and TypeScript, the tricky parts

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wolfhoundjesse profile image
Jesse M. Holmes •

I ran into something in this category with mocking a module with jest.mock().

import { fetchResource } from 'utils/api'

jest.mock('utils/api')
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This alone is enough to mock fetchResource, but with TypeScript we still get the intellisense from the original function rather than the mock function. I just reassigned fetchResource and typed the new function:

import { fetchResource } from 'utils/api'

jest.mock('utils/api')
const mockFetch = fetchResource as jest.Mock
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Finally I had access to things like fetchResource.mockResolvedValueOnce()

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learosema profile image
Lea Rosema (she/her) •

Cool, learned something new today, thank you =)

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pscoriae profile image
Pierre Cesario •

You just ended my hour long search for a solution. Many thanks!