Received 'Could not find a declaration file for module 'jest-extended/all' when importing jest-extended

[hollygcraig]

Bug

I followed the (setup instructions)[https://jest-extended.jestcommunity.dev/docs/getting-started/setup] for using jest-extended with vitest. I had a typescript setup file, testSetup.ts, with:

import {expect} from "vitest";
import * as matchers from "jest-extended";
expect.extend(matchers);

and included the following in vite.config.ts

setupFiles: ["./testSetup.ts"]

However, I would receive the error 'Could not find a declaration for module 'jest-extended/all' when importing jest-extended in the testSetup.ts file.

Workaround
It appears that the root cause of this was that jest-extended does not provide type definitions for the module itself. A way around this, if you have a similar setup to me, is to replace the line in vite.config.ts where we have setupFiles: ["./testSetup"] with setupFiles: ["jest-extended/all"]. This works as the setup files is a javascript (rather than a typescript) file supplied by jest-extended, so we don't need type definitions for it.