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Add support for Jest 27

See original GitHub issue

🐛 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 " > ts-jest@26.5.6" 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"

Issue Analytics

State:
Created 2 years ago
Reactions:19
Comments:17

Top GitHub Comments

11reactions

ahnpnlcommented, May 30, 2021

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

11reactions

ahnpnlcommented, May 25, 2021

27.0.0 was out

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