Unexpected token (SyntaxError) after updating Jest testing libraries

Question

When running my test suite using Jest, I encountered warnings that asked me to update packages:

npm WARN deprecated [email protected]: 🚨 jest-dom has moved to @testing-library/jest-dom. Please uninstall jest-dom and install @testing-library/jest-dom instead, or use an older version of jest-dom. Learn more about this change here: https://github.com/testing-library/dom-testing-library/issues/260 Thanks! :)
npm WARN deprecated [email protected]: 🚨  react-testing-library has moved to @testing-library/react. Please uninstall react-testing-library and install @testing-library/react instead, or use an older version of react-testing-library. Learn more about this change here: https://github.com/testing-library/dom-testing-library/issues/260 Thanks! :)

In package.json I changed the following

"jest-dom": "^2.1.1",
"react-testing-library": "^5.3.0"

to

"@testing-library/jest-dom": "^5.11.1",
"@testing-library/react": "^10.4.7"

and of course the import statements from

import "jest-dom/extend-expect";

to

import "@testing-library/jest-dom";

etc.

After I removed the old ones and added the new one, I got multiple error that makes my tests fail (only in my Semaphore CI setup, not on my local machine).

FAIL src/redux/actions/tests/myActions.test.js
  ● Test suite failed to run
    Jest encountered an unexpected token
    This usually means that you are trying to import a file which Jest cannot parse, e.g. it's not plain JavaScript.
    By default, if Jest sees a Babel config, it will use that to transform your files, ignoring "node_modules".
    Here's what you can do:
     • 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/en/configuration.html
    Details:
    /home/semaphore/my-app/client/node_modules/@testing-library/dom/dist/helpers.js:44
        } catch {// not using Jest's modern fake timers
                ^
    SyntaxError: Unexpected token {
      at ScriptTransformer._transformAndBuildScript (node_modules/jest-runtime/build/script_transformer.js:403:17)
      at Object.<anonymous> (node_modules/@testing-library/dom/dist/pretty-dom.js:13:16)
      at Object.<anonymous> (node_modules/@testing-library/dom/dist/config.js:11:18)

I am not a frontend developer, so I am happy to hear what more information is needed to facilitate help. Thanks a lot!

Answer 1

The error refers to optional catch binding, which is modern JS feature and supported since Node 10. This means that @testing-library/dom package doesn't support older Node versions, this can be confirmed by checking engines section in its package.json.

A preferable solution is to update Node.js because 8 reached the end of life. Alternatively, the package can be downgraded to lower major version or transpiled by white-listing it in transformIgnorePatterns, as the error suggests.