jest@28 support

[kirillgroshkov]

🚀 Feature Proposal

Jest 28 has landed.

Doesn't work with current ts-jest as-is, gives this error:

 FAIL  src/test/env.test.ts
  ● Test suite failed to run

    ● Invalid return value:
      Code transformer's `process` method must return an object containing `code` key 
      with processed string. If `processAsync` method is implemented it must return 
      a Promise resolving to an object containing `code` key with processed string.
      Code Transformation Documentation:
      https://jestjs.io/docs/code-transformation
      
      at ScriptTransformer._buildTransformResult (node_modules/@jest/transform/build/ScriptTransformer.js:504:15)
      at ScriptTransformer.transformSource (node_modules/@jest/transform/build/ScriptTransformer.js:623:17)
      at ScriptTransformer._transformAndBuildScript (node_modules/@jest/transform/build/ScriptTransformer.js:760:40)
      at ScriptTransformer.transform (node_modules/@jest/transform/build/ScriptTransformer.js:817:19)

Created this issue to track when jest28 support will land here.

Thanks.

Motivation

 

Example

No response

[SimenB]

The fix should be trivial fwiw, just make sure

ts-jest/src/legacy/ts-jest-transformer.ts

Line 236 in 6e44f82

private runTsJestHook(

returns an object (which has worked for years, so backwards compatible if that matters).

jestjs/jest#12638

[ahnpnl]

We had a release at next tag yesterday. Please try it out:)

[SimenB]

Ah, nice!

(Should've pinged you when making the change @ahnpnl, sorry about that)

[dante01yoon]

It ts-jest latest version doesn't support jest 28 yet?

[Snaptags]

Using the next version at least the tests succeed, but I still get lots of warnings:

ts-jest[ts-jest-transformer] (WARN) Use 'ts-jest' entry point in v28 will resolve in refactored transformer. If you wish to use legacy transformer, please adjust your Jest 'transform' config. For example:
     module.exports = {
        transform: {
           '^.+\\.tsx?$': 'ts-jest/legacy'
        }
     }

[huineng]

true, but like the message says, if you include this in your jest.config.js that warning goes away

     module.exports = {
        transform: {
           '^.+\\.tsx?$': 'ts-jest/legacy'
        }
     }

[Snaptags]

Thanks! Adding /legacy to something does not sound very future-proof, though :-D

[ahnpnl]

Thanks! Adding /legacy to something does not sound very future-proof, though :-D

We plan a refactoring to switch to esbuild/swc as default for v28. Marking the current codes as legacy to ensure that we still have a backup with and let users have more time to adopt to new one.

[Ezard]

Is there already a built-in way to use esbuild/swc with v27?

If not then would it be worth making it opt-in for v28, and then making it the default (with legacy option also available) in v29 once stability/compatibility/etc has been ensured?

[ahnpnl]

Is there already a built-in way to use esbuild/swc with v27?

If not then would it be worth making it opt-in for v28, and then making it the default (with legacy option also available) in v29 once stability/compatibility/etc has been ensured?

Nope we don't have it built in for v27 yet. Have it opt-in for v28 seems to be easier in term of refactoring.

[cwadrupldijjit]

I haven't had any luck running my tests at all, even when updating to the latest versions of jest and ts-jest@next. I'll peruse for an issue that's currently open for what I'm looking at, but so far, the only ones I can see are closed and do not have suggestions that have fixed them. The warning that was mentioned to add the transform with ts-jest/legacy isn't seeming to work to suppress all of the warnings and no matter what I've tried to do, nothing succeeds. Every test is currently failing and I'm not quite sure why.

For reference, the versions I'm using are jest@28.0.0, ts-jest@28.0.0-next.1, node@18.0.0 and I'm running on Windows 11 Pro, x64.

[ahnpnl]

I haven't had any luck running my tests at all, even when updating to the latest versions of jest and ts-jest@next. I'll peruse for an issue that's currently open for what I'm looking at, but so far, the only ones I can see are closed and do not have suggestions that have fixed them. The warning that was mentioned to add the transform with ts-jest/legacy isn't seeming to work to suppress all of the warnings and no matter what I've tried to do, nothing succeeds. Every test is currently failing and I'm not quite sure why.

For reference, the versions I'm using are jest@28.0.0, ts-jest@28.0.0-next.1, node@18.0.0 and I'm running on Windows 11 Pro, x64.

What exactly not working? Do you have a reproduce scenario?