Can we use ts-jest without babel typescript preset?

[kachar]

From https://jestjs.io/docs/getting-started#using-typescript-via-ts-jest it looks like we have an option to use TS with Babel or with ts-jest

I would like to stop using babel in my project, but currently, the tests fail when I remove babel.config.js

Jest encountered an unexpected token

Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax.

Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration.

By default "node_modules" folder is ignored by transformers.

Here's what you can do:
• If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/ecmascript-modules for how to enable it.
• If you are trying to use TypeScript, see https://jestjs.io/docs/getting-started#using-typescript
• To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
• If you need a custom transformation specify a "transform" option in your config.
• If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.

Do you have any suggestion how to use only ts-jest for my tests?

// babel.config.js
module.exports = {
  presets: [['@babel/preset-env', { targets: { node: 'current' } }], '@babel/preset-typescript'],
}

[ahnpnl]

You can take a look at our examples https://github.com/kulshekhar/ts-jest/tree/main/examples

[kachar]

I've built my testing setup around the examples, but the typescript types and interfaces are not being recognized in the test files.

jest.config.js

/** @type {import('ts-jest/dist/types').InitialOptionsTsJest} */
module.exports = {
  preset: 'ts-jest/presets/js-with-ts-esm',
  extensionsToTreatAsEsm: ['.ts'],
  globals: {
    'ts-jest': {
      useESM: true,
      tsconfig: 'tsconfig.spec.json',
    },
  },
  testMatch: ['**/*.test.ts'],
  moduleNameMapper: {
    '^(\\.{1,2}/.*)\\.js$': '$1',
  },
  testEnvironment: 'node',
  projects: ['./libs/*', './services/*'],
  collectCoverageFrom: ['./libs/**/*.ts', './services/**/*.ts'],
}

tsconfig.spec.json

{
  "compilerOptions": {
    "module": "esnext",
    "target": "esnext",
    "esModuleInterop": true,
    "allowJs": true
  }
}

I'll try to do a repo that reproduces the scenario

[kachar]

@ahnpnl I've been able to reproduce the scenario in dedicated repo https://github.com/kachar/ts-jest-no-babel

You may find the error via no babel approach on master branch and the babel configuration on with-babel branch

The actual problem occurs when we try to add a typescript type inside the .spec.ts file

type TestOne = {
  name: string;
};

Once we remove the type the version on master branch has the expected result