Typescript support

[kirillgroshkov]

Feature request: would be awesome if it supported typescript compilation (no type-checking needed).

Maybe something simple like esbuild transformer can be added for *.ts files, that'll cover 99% of the common needs.

Awesome runner, by the way!

[cspotcode]

I bet you can use ts-node's ESM loader to do this today. Turn on swc mode for speed.

[cspotcode]

I made a demo combining ts-node with this test runner:
https://github.com/TypeStrong/ts-node-repros/tree/jest-light-runner/

I see that esmock is mentioned in the readme. If you want to combine ts-node with esmock or any other loader, try this:
https://www.npmjs.com/package/@cspotcode/multiloader
Or wait for node to release loader chaining support.

[kirillgroshkov]

@cspotcode awesome, it works!

I'll close the issue then! 👍

[cspotcode]

Any chance this can be added to the README?

[nicolo-ribaudo]

Thank you @cspotcode! I'll create an "examples" folder that shows both this and how to mock ES modules using a loader.

[iambumblehead]

from this PR and discussion iambumblehead/esmock#155 we found that, using the latest node v18.9.0...

jest + jest-light-runner + ts-node/esm do not work are working, cc @cspotcode

{
  "extends": "ts-node/node16/tsconfig.json",
  "ts-node": {
    "transpileOnly": true,
    "files": true
  },
  "compilerOptions": {
    "allowSyntheticDefaultImports": true,
    "module": "ESNext",
    "moduleResolution": "node"
  }
}

{
  "type": "module",
  "description": "esmock unit tests, jest with ts and jest-light-runner",
  "dependencies": {
    "ts-node": "^10.9.1",
    "jest": "^29.0.3",
    "jest-light-runner": "0.4.0",
    "run-script-os": "^1.1.6"
  },
  "jest": {
    "runner": "jest-light-runner"
  },
  "scripts": {
    "test:default": "NODE_OPTIONS=\"--loader=ts-node/esm\" jest test.ts",
    "test:win32": "set NODE_OPTIONS=\"--loader=ts-node/esm\" && jest test.ts",
    "test": "run-script-os"
  }
}

 PASS  ./test.ts
  ✓ should pass a test when using jest

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        1.101 s
Ran all test suites matching /test.ts/i

jest + jest-light-runner + tsm are working

{
  "type": "module",
  "description": "esmock unit tests, jest with ts and jest-light-runner",
  "dependencies": {
    "tsm": "^2.2.2",
    "jest": "^29.0.3",
    "jest-light-runner": "0.4.0",
    "run-script-os": "^1.1.6"
  },
  "jest": {
    "runner": "jest-light-runner"
  },
  "scripts": {
    "test:default": "NODE_OPTIONS=\"--loader=tsm\" jest test.ts",
    "test:win32": "set NODE_OPTIONS=\"--loader=tsm\" && jest test.ts",
    "test": "run-script-os"
  }
}

 PASS  ./test.ts
  ✓ should pass a test when using jest

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        0.792 s
Ran all test suites matching /test.ts/i

[cspotcode]

Looks like you do not want typechecking, and you got a typechecking error here. So I would turn off typechecking. transpileOnly should do the trick.

[iambumblehead]

@cspotcode thank you, with this tsconfig.json, the ts-node test is passing. I will update the comment above shortly,

{
  "extends": "ts-node/node16/tsconfig.json",
  "ts-node": {
    "transpileOnly": true,
    "files": true
  },
  "compilerOptions": {
    "allowSyntheticDefaultImports": true,
    "module": "ESNext",
    "moduleResolution": "node"
  }
}

[cspotcode]

Sounds good, you can also remove the files option since that one only affects typechecking. With transpileOnly enabled, it has no effect.

[iambumblehead]

the person who opened the issue at esmock, @cyberwombat, also wants to use a jest.config.ts file that looks like this,

export default {
  testEnvironment: 'jest-environment-node',
  setupFiles: ['./test/setup.ts'],
  setupFilesAfterEnv: ['./test/bootstrap.ts'],
  transform: {
    '^.+\\.tsx?$': [
      'ts-jest',
      {
        useESM: true,
        diagnostics: false,
        compilerHost: true,
        incremental: true
      }
    ]
  },
  moduleNameMapper: {
    '^(\\.{1,2}/.*)\\.js$': '$1',
    '^lib/(.*)$': 'src/lib/$1'
  },
  extensionsToTreatAsEsm: ['.ts'],
  testPathIgnorePatterns: ['<rootDir>/dist', '.history'],
  modulePaths: ['<rootDir>/src', '<rootDir>/test', '<rootDir>'],
  preset: 'ts-jest'
}

Is it possible to support this, while using jest-light-runner with --loader=ts-node/esm?

[iambumblehead]

ts-node fails in windows CI pipeline, seemingly because of the slash "/" in "ts-node/esm"

{
  "scripts": {
    "test:win32": "set NODE_OPTIONS=\"--loader=ts-node/esm --loader=esmock\" && jest esmock.node-jest.test.ts"
  }
}

https://github.com/iambumblehead/esmock/actions/runs/3091643663/jobs/5001967546

Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './esm --loader=esmock' is not defined by "exports" in D:\a\esmock\esmock\tests\tests-jest-ts\node_modules\ts-node\package.json imported from D:\a\esmock\esmock\tests\tests-jest-ts\
    at new NodeError (node:internal/errors:393:5)
    at throwExportsNotFound (node:internal/modules/esm/resolve:340:9)

[cspotcode]

Mistake in your quoting

Package subpath './esm --loader=esmock' is not defined by "exports"

It thinks the subpath is this full string:

esm --loader=esmock

Cuz of a mistake in quoting

[iambumblehead]

it seems the solution is so obvious, no explanation is needed :) but I do not know the solution. I think I understand the problem you are pointing out, but I don't know how to solve it

[liuxingbaoyu]

https://stackoverflow.com/questions/535975/dealing-with-quotes-in-windows-batch-scripts

Does this work?
"test:win32": "set \"NODE_OPTIONS=--loader=ts-node/esm --loader=esmock\" && jest esmock.node-jest.test.ts"

[iambumblehead]

the suggestion will be used in the test pipeline here https://github.com/iambumblehead/esmock/actions/runs/3091925933/jobs/5002604159 @liuxingbaoyu it worked! I was not able to solve that --thank you for that suggestion