[Bug]: Declare ts-node as dependency of jest-config

[yohny]

Version

29.7.0

Steps to reproduce

When you have a new project with Jest set up as testing framework and you are using a typescript configuration files you get following error when launching jest tests:

Error: Jest: Failed to parse the TypeScript config file C:\Users\nej\source\repos\ddnp-gui\jest.config.ts
  Error: Jest: 'ts-node' is required for the TypeScript configuration files. Make sure it is installed
Error: Cannot find package 'ts-node' imported from C:\Users\nej\source\repos\ddnp-gui\node_modules\jest-config\build\readConfigFileAndSetRootDir.js
    at readConfigFileAndSetRootDir (C:\Users\nej\source\repos\ddnp-gui\node_modules\jest-config\build\readConfigFileAndSetRootDir.js:116:13)
    at async readInitialOptions (C:\Users\nej\source\repos\ddnp-gui\node_modules\jest-config\build\index.js:403:13)
    at async readConfig (C:\Users\nej\source\repos\ddnp-gui\node_modules\jest-config\build\index.js:147:48)
    at async readConfigs (C:\Users\nej\source\repos\ddnp-gui\node_modules\jest-config\build\index.js:424:26)

Expected behavior

Threre should be no error as typescript configuration is supported according to docs. So expected behaviour is that ts-node should be declared as peerDependency of jest-config. Once ts-node is installed alll works as expected.

Actual behavior

You get error above when running jest tests using typescript configuration, because ts-node is not declared as dependency of jest-config (its only in devDependencies of jest-config).

Additional context

No response

Environment

System:
  OS: Windows 10 10.0.19045
  CPU: (12) x64 Intel(R) Core(TM) i7-8850H CPU @ 2.60GHz
Binaries:
  Node: 20.10.0 - C:\Program Files\nodejs\node.EXE
  npm: 10.2.3 - C:\Program Files\nodejs\npm.CMD
npmPackages:
  jest: ^29.7.0 => 29.7.0

[habtim]

Hey @yohny
As stated https://jestjs.io/docs/getting-started#using-typescript, you can either use babel or ts-node.
None of which is installed by default and it's up to you to define which way to go.
Also note (when using ts-node)

In order for Jest to transpile TypeScript with ts-jest, you may also need to create a configuration file.

Should work as expected.

[yohny]

yes, the docs mention 2 alternatives - babel and ts-jest (not ts-node), but for babel case it is only mentioned to install @babel/preset-typescript and for ts-jest case its only mentioned to install ts-jest. Nothing about the need to install ts-node. Can than at least the docs be updated to reflect the reality?
Also when ts-node is required to be installed for ts-jest alternative to work, should it not be in its peerDependencies? Isn't that what peerDependencies are for? Or am I missing something?

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[yohny]

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[yohny]

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[djsiddz]

If someone needs a temporary workaround using yarn, I'm leaving this code here. Add a .yarnrc.yml file to the root of your project. Include the below code:

packageExtensions: {
  jest-config@29.7.0: {
    dependencies: {
      ts-node: ">=9.0.0"
    }
  }
}

After adding the file, run yarn install. Then yarn build or yarn dev should work fine. It worked for me.

I faced this issue with Jest v29.7.0. I've assumed jest-config's version to be in sync with jest.
Also ts-node's version has been picked from jest-config's package.json here available today.

Once this is fixed in Jest's future release, the .yarnrc.yml file or at least the above lines can be safely removed from this file.

P.S.: Possibly, your first thought would be to use yarn patch. However, the dependencies are computed at fetch time and not at resolution time. Hence packageExtensions is the way to go.

References:
Yarn Package Patching - See Limitations
Yarn Settings (.yarnrc.yml) - See packageExtensions

Learnt this when I faced a similar issue with Astro here.

Hope this helps!

[marco-carvalho]

@SimenB shouldn't ts-node be in dependencies of jest-config? https://github.com/jestjs/jest/blob/main/packages/jest-config/package.json

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 30 days.

[marco-carvalho]

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