Add support for Jest 27

[ayuhito]

🐛 Bug Report

Upgrading to Jest 27 leads to the following error:
TypeError: Jest: a transform must export something.

Also the peer dependency scope should be updated alongside this fix:
warning " > [email protected]" has incorrect peer dependency "jest@>=26 <27".

To Reproduce

Upgrade from Jest 26 to Jest 27.

Expected behavior

Running the jest command to successfully run tests.

Debug log:

# content of ts-jest.log :
{"context":{"allowJs":false,"logLevel":20,"namespace":"jest-preset","package":"ts-jest","version":"26.5.6"},"message":"creating jest presets not handling JavaScript files","sequence":1,"time":"2021-05-25T10:57:05.252Z"}
{"context":{"allowJs":false,"logLevel":20,"namespace":"jest-preset","package":"ts-jest","version":"26.5.6"},"message":"creating jest presets not handling JavaScript files","sequence":2,"time":"2021-05-25T10:57:05.265Z"}
{"context":{"logLevel":20,"namespace":"Importer","package":"ts-jest","version":"26.5.6"},"message":"creating Importer singleton","sequence":3,"time":"2021-05-25T10:57:05.980Z"}

envinfo

System:
    OS: Windows 10
    Node version: 15.12.0

Npm packages:
    "jest": "^27.0.1",
    "ts-jest": "^26.5.6",
    "typescript": "^4.2.4"

[ahnpnl]

Thanks for notification, we already prepare for it at next tag so we will prepare for latest tag soon.

[brettdorrans]

@ahnpnl Can you give some indication of when soon is? Also, it would be helpful to keep this issue open while the problem exists, I had assumed it was resolved given you'd closed it.

[ahnpnl]

it is resolved in next tag. If you are in a hurry, you can use ts-jest@next. next tag is basically ready to release.

[brettdorrans]

Ideal, thank you.

[mishakorablin]

@ahnpnl, looks like npm still points next to 27.0.0-next.12, which was published awhile back. It currently supports jest until 27.0.0-next9. However, latest jest release is 27.0.1

[ahnpnl]

next tag is fully compatible despite the warning message. You can temporarily use next tag if you are in a hurry :) ts-jest 27 will be released within this week.

[ahnpnl]

27.0.0 was out

[sauldeleon]

Hello, I am having this issue in 27.0.1

    "ts-jest": "27.0.1"

It is related with this?

[ahnpnl]

Please clear Jest cache.

Also check your lock file to make sure ts-jest is 27.0.1

You can also remove node_modules and reinstall deps.

[sauldeleon]

Thanks @ahnpnl for your (I must say) incredibly fast response.

I have:

• Cleared jest cache doing jest --showConfig | grep "cache" and removed all cache directories listed by the command, also runned jest --clearCache
• removed node_modules
• confirmed yarn.lock is 27.0.1

Unfortunately, error keeps there :(

I can provide a repo if needed

Edit: Testing repo here

[ahnpnl]

You are using Jest 26 with ts-jest 27, which is not a valid combination, see https://github.com/sauldeleon/monorepo-starter/blob/623bc73b10f1a33f3f73695d96cf8c473c7aaedc/yarn.lock#L1744. ts-jest major version always follows Jest major version. For example: Jest 26 with ts-jest 26, Jest 27 with ts-jest 27

[sauldeleon]

thanks a lot @ahnpnl . As you said, this was the issue. Seems that CRA installs jest 26! Thanks a lot

EDIT: for whoever reaching this post, if you are using react-scripts 4.0.3 or below, it internally uses jest 26, so installing ts-jest 27 will crash everything.

You can force react-scripts to use jest 27 using yarn resolutions feature to force react-scripts to use jest 27, or wait until react-scripts updates internal dependency

[suvasishm]

I am still facing the issue while upgrading jest and ts-jest to v27. Tried npx jest --clearCache.

"jest": "^27.0.6",
"ts-jest": "^27.0.5",
"@types/jest": "^27.0.1"

Using Windows 10 and

"engines": {
    "node": ">=14.16.1",
    "npm": ">=6.14.12"
}

[peterphan1996]

I'm having the same problem as @suvasishm

[DanielUche]

I'm having the same problem as @suvasishm

[juanguren]

Hey everyone!
Following up on this thread, one basic question: How can I upgrade the versions of jest and @types/jest? (NPM)
I immediately assumed a npm i -D jest.. would do so automatically, but both versions remain at 26 and I need all of them to be at 27. I'm trying to solve this error -

I'd appreciate your help!

[juanguren]

Hey everyone!
Following up on this thread, one basic question: How can I upgrade the versions of jest and @types/jest? (NPM)
I immediately assumed a npm i -D jest.. would do so automatically, but both versions remain at 26 and I need all of them to be at 27. I'm trying to solve this error -

I'd appreciate your help!

I managed to solve it. Just run the npm install ts-jest@27 (npm install {package}@{version}) command. Applicable to any package.