[Bug]: Version 29.2.1 breaks default imports

[flovouin]

Version

29.2.1

Steps to reproduce

1. Clone https://github.com/flovouin/ts-jest-default-imports-bug/.
2. Run npm i && npm run build. TypeScript compilation should succeed.
3. Run npm test.

Expected behavior

npm test should pass with no error.
You can install ts-jest version 29.2.0 instead and see it succeed.

Actual behavior

$ npm test

> [email protected] test
> NODE_OPTIONS="$NODE_OPTIONS --experimental-vm-modules --no-warnings=ExperimentalWarning" jest

 FAIL  src/index.spec.ts
  ● Test suite failed to run

    src/index.ts:2:28 - error TS2351: This expression is not constructable.
      Type 'typeof import("[..]/node_modules/i18next-fs-backend/cjs/index")' has no construct signatures.

    2 export const backend = new Backend();
                                 ~~~~~~~

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        0.38 s
Ran all test suites.

For what it's worth, even though I wasn't expecting to see the CJS version imported, node_modules/i18next-fs-backend/cjs/index does exist and export a default class.

Debug log

ts-jest.log

Additional context

No response

Environment

System:
    OS: macOS 14.5
    CPU: (10) arm64 Apple M1 Max
  Binaries:
    Node: 20.12.1 - ~/.asdf/installs/nodejs/20.12.1/bin/node
    npm: 10.8.2 - ~/.asdf/plugins/nodejs/shims/npm
  npmPackages:
    jest: ^29.7.0 => 29.7.0

[ahnpnl]

I could understand why it worked at 29.2.0 because we always used target: ESNext for ESM mode and Node16/NodeNext wasn't taken into account.

For some reasons, ts-jest starts throwing type error related when taking into account of Node16/NodeNext in your case.

As a workaround, you can use target: ESNext which should fix the issue

[flovouin]

Thanks for the reply! Indeed, updating the Jest configuration does the trick:

  transform: {
    "^.+\\.ts$": ["ts-jest", { useESM: true, tsconfig: { module: "ESNext" } }],
  },

I'll let you keep the issue around or close it depending on how you want to address this. In my case it's probably an acceptable compromise, even though it may create new problems down the line.