Error with node_modules package, transformIgnorePatterns doesn't help

[msakrejda]

Hello,

I'm running into an issue with transforming a dependency. At first glance, it looked like this FAQ answer is exactly what I'm hitting, but applying that doesn't change anything.

I have Remix project with TypeScript, and parse5-sax-parser as a dependency. When I try to run a test that references the module, I get an error from jest:

 FAIL  app/services/parser.server.test.ts
  ● Test suite failed to run

    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.

    You'll find more details and examples of these config options in the docs:
    https://jestjs.io/docs/configuration
    For information about custom transformations, see:
    https://jestjs.io/docs/code-transformation

    Details:

    /home/maciek/code/ts-jest-repro/repro/node_modules/parse5-sax-parser/dist/index.js:1
    ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){import { Transform } from 'node:stream';
                                                                                      ^^^^^^

    SyntaxError: Cannot use import statement outside a module

    > 1 | import { SAXParser } from "parse5-sax-parser";
        | ^
      2 |
      3 | export function parse(text: string): boolean {
      4 |   console.log(SAXParser);

      at Runtime.createScriptFromCode (node_modules/jest-runtime/build/index.js:1495:14)
      at Object.<anonymous> (app/services/parser.server.ts:1:1)
      at Object.<anonymous> (app/services/parser.server.test.ts:3:1)

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        2.07 s
Ran all test suites.

I've created an isolated reproduction here: https://github.com/msakrejda/jest-ts-error-repro. Note that my jest.config.js there is

/** @type {import('ts-jest').JestConfigWithTsJest} */
module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'node',
  transformIgnorePatterns: ["node_modules/(?!parse5-sax-parser)"]
};

which should account for this package, right?

Any ideas?

It looks like this may be related to this discussion, but that's unanswered and I'm not sure it's the same thing, so I'm starting a new one.

[msakrejda]

I switched to vitest and my test started working. No changes needed—seamless migration. I can even remove my jest.config.js.

[i-am-gizm0]

For anyone who is running into this problem in the future and doesn't want to move away from Jest, I was stuck on a similar issue for hours yesterday; my solution was to set preset: 'ts-jext/presets/js-with-ts along with the transformIgnorePatterns in my jest.config.js and setting "compilerOptions": { "allowJs": true } in my tsconfig.json