Jest fails to import detectors when testing in NodeJS

[phil714]

Describe the bug

Hi,

I've been trying to run my test since I added typesafe-i18n to my backend but I've been running into a problem. While testing manually to see if the translations were working right, everything seems to be working well but while running the tests, my tests that were testing files that used the translation were failing. It seems to fail to import the detectors in the utils file and causing everything else to fail.

Reproduction

cross-env NODE_ENV=test jest --verbose --maxWorkers=3

Logs

FAIL  tests/integration/mutations/productMutation/productCreate.test.ts
  ● Test suite failed to run

    Cannot find module 'typesafe-i18n/detectors' from 'src/i18n/i18n-util.ts'

    Require stack:
      src/i18n/i18n-util.ts
      src/i18n/i18n-node.ts
      src/i18n/index.ts
      src/graphql/resolvers/auditLogQuery/resolvers.ts
      src/graphql/resolvers/query/resolvers.ts
      src/graphql/index.ts
      tests/helpers/apolloServerHelper.ts
      tests/integration/mutations/productMutation/productCreate.test.ts

       6 | import type { Translation, TranslationFunctions, Formatters, Locales } from './i18n-types'
       7 | import type { LocaleDetector } from 'typesafe-i18n/detectors'
    >  8 | import { detectLocale as detectLocaleFn } from 'typesafe-i18n/detectors'
         | ^
       9 | import { initFormatters } from './formatters'
      10 |
      11 | export const baseLocale: Locales = 'en'

      at Resolver.resolveModule (node_modules/jest-resolve/build/resolver.js:311:11)
      at Object.<anonymous> (src/i18n/i18n-util.ts:8:1)

Config

{
   "adapter": "node",
   "loadLocalesAsync": false,
   "$schema": "https://unpkg.com/typesafe-i18n@2.53.2/schema/typesafe-i18n.json"
}

Additional information

I'm on MacOS and using NodeJS 16.9.0 and we're using Jest 27.0.4 & cross-env 7.0.3 for the project.

I also tried adding typesafe-i18n --no-watch && in front of my test command to generate the translations before the tests but with no result. My suspicion is that there is a problem with how the subdirectory is imported (or setup on your side, I'm not really sure) because it fails at the line where the detector is imported but not the one where the i18nString, i18nObject function are imported.

We also added a small wrapper around i18nObject which is why it's going through src/i18n/index.ts.

// src/i18n/index.ts
import { i18nObject } from './i18n-node';

export const LL = i18nObject;

We don't use the detector but we can't remove this particular code because it is generated each time. I'm a bit at a lost on what to do honestly so if you have any ideas on what can causes this, let me know.

[ivanhofer]

Hi @phil714,
thanks for creating this issue.

I think this is still the same issue as described here:
#71 (comment).
It seems that jest does not support modern import resolutions.
Nobody could provide me with more details so I closed the issue back then.

I'm no jest user, so I don't really know how to start investigating this.
Could you please create a small repo, with jest so I can test a few things?

As a workaround you could enable the generateonlytypes option and then manually remove the detector-import from the i18n-util.ts file.
When running the generator again, only the i18n-types.ts file get's recreated.

[phil714]

Hi,

Thank you for the quick response.

I've tried upgrading all our Jest-related librairies to the latest version and the issue seems to remain. I have looked at some issues linked in your other comments and like you said, (from what I understood) it doesn't look like their library support ESM resolution. It look like they are working on it but it might take a while.

jestjs/jest#9430
jestjs/jest#9771

I think for now I'll follow your advice of adding the flag and removing the detector from my util file. If you still think this is worth investigating on your side, I can make a small test repository with the problem.

[ivanhofer]

Would be great if you could provide me with an example repo, so I can take a look at how easy or hard it is to fix it 😊

[phil714]

Here goes @ivanhofer https://github.com/phil714/stunning-octo-chainsaw-jest-typesafe-i18n-test.

I've manage to reproduce it with minimal configuration. You should just have to install everything doing npm i and then run the test with npm run test. I've copied a large part of our tsconfig.json file since I'm honestly not an expert on how all of these options can affect the problems or not. Let me know if there's more I can do.

[ivanhofer]

@phil714 thanks for the repo! I will take a deeper look when I find some time :)

[thanoskrg]

Not sure whether this is the same issue I had with react where jest could not find module typesafe-i18n/adapters/adapter-react but this is how I managed to solve it by using the moduleNameMapper config option likewise:

// jest.config.js

module.exports = {
  preset: "ts-jest",
  testEnvironment: "jsdom",
  transformIgnorePatterns: ["node_modules"],
  setupFilesAfterEnv: ["<rootDir>/setupTests.ts"],
  moduleNameMapper: {
    "typesafe-i18n/adapters/(.*)": "typesafe-i18n/adapters/$1.cjs",
    "typesafe-i18n/detectors": "typesafe-i18n/detectors/index.cjs",
  },
};

Hope this helps.

[ivanhofer]

@thanoskrg thanks for sharing your solution 👍

[ivanhofer]

@phil714 I just tested the moduleNameMapper solution above and it works for me. Can you please verify if this is also working in your project?

[ivanhofer]

I have added a troubleshoot section to the docs: https://github.com/ivanhofer/typesafe-i18n#tests-are-not-running-with-jest