[Bug]: Unexpected token 'export' when testEnvironment is `jsdom`

Version

29.0.2

Steps to reproduce

check out https://github.com/rburgst/test-ts-jest

pnpm install
pnpm jest

You will get

    SyntaxError: Unexpected token 'export'

    > 1 | import { createRef } from 'preact'
        | ^
      2 |
      3 |
      4 | export function foo() {

      at Runtime.createScriptFromCode (node_modules/.pnpm/jest-runtime@29.0.3/node_modules/jest-runtime/build/index.js:1678:14)
      at Object.<anonymous> (src/index.ts:1:1)
      at Object.<anonymous> (src/index.test.ts:1:1)

I tried switching the whole project over to ESM but that showed a similar problem (see esm branch).

Expected behavior

the test should run successfully

Actual behavior

You will get

    SyntaxError: Unexpected token 'export'

    > 1 | import { createRef } from 'preact'
        | ^
      2 |
      3 |
      4 | export function foo() {

      at Runtime.createScriptFromCode (node_modules/.pnpm/jest-runtime@29.0.3/node_modules/jest-runtime/build/index.js:1678:14)
      at Object.<anonymous> (src/index.ts:1:1)
      at Object.<anonymous> (src/index.test.ts:1:1)

Debug log

that file is rather large

Additional context

Repro repo: https://github.com/rburgst/test-ts-jest

Environment

System:
    OS: macOS 12.6
    CPU: (10) arm64 Apple M1 Pro
  Binaries:
    Node: 16.17.0 - ~/.volta/tools/image/node/16.17.0/bin/node
    Yarn: 1.22.18 - ~/.volta/tools/image/yarn/1.22.18/bin/yarn
    npm: 8.15.0 - ~/.volta/tools/image/node/16.17.0/bin/npm
  npmPackages:
    jest: ^29.0.3 => 29.0.3

[rburgst]

@ahnpnl thanks a lot for the explanation, with your config I can confirm that it works now. I am just flabbergasted that it takes so much configuration to get this to work when in ts-jest (and jest) 27 everything worked out of the box.

[ahnpnl]

it seems it ignores the tsconfig when inlined but used it if globals. however if globals, a warning to migrate is displayed with jest 29

module.exports = {
  preset: "ts-jest",
  globals: {
    "ts-jest": {
      tsconfig: {
        allowJs: true,
      },
    },
  },
  testEnvironment: "node",
  setupFiles: [`<rootDir>/test-setup.ts`],
  transform: {
    "^.+\\.(t|j)s$": "ts-jest",
  },
};

no issue but warning

ts-jest[ts-jest-transformer] (WARN) Define ts-jest config under globals is deprecated. Please do transform: { <transform_regex>: [‘ts-jest’, { /* ts-jest config goes here in Jest */ }], },

following solved warning

module.exports = {
  preset: "ts-jest",
  testEnvironment: "node",
  setupFiles: [`<rootDir>/test-setup.ts`],
  transform: {
    "^.+\\.(t|j)s$": ["ts-jest", {
      tsconfig: {
        allowJs: true,
      },
    }]
  },
};

but lead in my case to the error Unexpected token 'export' because the tsconfig is not intepreted

You need to remove preset in this case. Because when Jest merges preset and transform, your transform config becomes this

transform: {
    "^.+\\.(t|j)s$": ["ts-jest", {
      tsconfig: {
        allowJs: true,
      },
    }],
    "^.+\\.[tj]sx?$": "ts-jest"
  },

Since your regex is not the same as the regex of the preset in ts-jest repo, which Jest will produce that result which leads to your problem https://github.com/kulshekhar/ts-jest/blob/588c0d35d8099f261a56e736485178c817b62065/src/presets/create-jest-preset.ts#L25

Documentation already includes the regex patterns ts-jest uses https://kulshekhar.github.io/ts-jest/docs/getting-started/options I think documentation just needs a bit updates about this kind of merging behavior from Jest.